Good evening everyone, and thank you for joining us for our first ever virtual BCVA Student clinical Club. My name is Sarah Peterson, I'm on the BCVA board, and I'll also be speaking tonight. Just a little bit of housekeeping before we start.

We're going to have, this is going to be a longer session than normal, so it's an hour and a half, so we'll have plenty of time for some interactive, question and answer sessions at the end. So if you've got any questions that come up during the the course of the presentation, then please put them in the Q&A box, at the bottom of the screen and we'll, we'll save them until the end of the presentation. Also, if you're having any technical difficulties, then we've got Rich from Webinarett on hand to deal with those.

So again, let us know by putting them in the Q&A box. If you can't see the Q&A box, if you move your mouse to the taskbar, the taskbar should become visible at the bottom of your screen, and you can just click on Q&A, there and enter your questions. So, just a little bit of background about myself.

I graduated from the RVC in 2005, having interclad at Bristol in zoology. And then I went straight into farm practise in Dorset. I spent around a year there, and then went and did a dairy internship based in Cheshire.

After about 10 years up there in practise with brief stints for Boringer and also volunteering in India, all still within in Derry, 6 years ago I moved back home to Cowbridge in South Wales, pretty apt place for a cow vet to live. Since then, I've been working for myself, and I've been focusing more and more on lameness, and pretty much now I spend all of my time in this area. I work with a number of different, organisations, as well as a num farmers all across the country trying to tackle lameness problems.

Alongside this, I'm also doing a part-time PhD on foot trimming at Nottingham, and juggling a toddler as well. So it's all pretty full on, but it's also really, really great, to still be working in this area. So, tonight, I'm gonna be talking about one of my favourite areas, and that is digital dermatitis.

This, this work that I'm presenting tonight actually formed part of a massive ALA project that we did, around 3 or 4 years ago now, and was rolled out across. Across all of the all the farmers, across the country. And as you'll see later on, it's had quite a big impact, in terms of digital dermatitis control, in herds.

So, in terms of our plan for tonight, first of all, I'll just talk a little bit about BCVA. I will have met many of you, at some of the FAS congress and ABS congress, but for those of you who don't know what BCVA is about, I just want to introduce you to us and, and all the board. Then we'll talk about why we're talking about DD.

Why is it an issue in our dairy farms? Then we'll talk about what it actually is and how we should be understanding the bug better to be able to further improve control on farm. And then I'm going to talk through a protocol, for control.

And this is a protocol that can be applied in any dairy herd, and, in fact, we've applied it in beef herds too. And, as long as all the, all the, criteria is stuck to, we can have really, really good results. So we'll talk about identification of digital dermatitis.

We'll talk about treatment, we'll talk about some of the evidence base behind this, and then we'll also talk a lot about prevention. Then I'll give you the results of a case study where we put this plan in action, and then we can finish up by summarising and having our question and answer session. So let's start by just introducing BCVA.

So we're the British Cattle Veterinary Association. We're a member organisation. We've got over 1500 members across the country.

We're established in 1967, so we've been going a long, long time now, with the specialist cattle division of the BVA and we work, very, very closely with the BVA and certainly given the current situation, we're working incredibly closely with them, to guide our members. We're an elected board of directors, we're all volunteers, so we're all doing other jobs alongside our BCVA work. And we're a great mix of practising vets, those from academic and also industry as well.

In terms of who's on the board currently, well, the board is updated every year, people serve, a 3-year term. After the 3 years is up, they can either step down or they can be elected to run another 3 years. Our current president is Nicky Hopkins, a farm animal vet based in Mid Wales, and she's being supported by our junior vice president, Elizabeth Berry, and the senior vice president Dave Barrett.

The other officers within BCVA are Phil Elkins, Colin Mason, Sally Wilson. And then there's a further 12 of us on the board who all have different roles on the board in terms of different areas that we, we look after. I'm obviously, involved in education, specifically lameness, and, obviously students as well.

So in terms of what we actually do, well, our mission is to be the voice of the cattle vet and also to drive tomorrow's practise. And it wasn't until I became involved with BCVA that I actually realised just how much BCVA is involved with. So in terms of health and welfare, we're involved in red tractor, CES, Chow, which is the health and welfare group, mastitis steering group, mobility steering group, BVD, the list goes on and on.

We also liaise with the government on a number of points. We've been involved in the production of the the recently released emergency slaughter document. We're also heavily involved in the animal health pathway as well.

We work closely with BVA and we also work closely on TB with a number of groups as well. When it comes to medicine, we're involved with rumour, cows, telemedicine and also antimicrobial groups. We've also got our education group involved in running the webinars, masterclasses, cattle practise and all our other CPD.

So you can see there's quite a lot that BCVA is involved with. So what about students? How can you get as involved as a student?

Well, we've got a great growing student membership. We offer e-membership, which is just 5 pounds from now until the day you graduate, or a full membership, which is 25 pounds per year. And for that, you get the same membership benefits that our full vets, graduated vets get.

So you get all the access to the, the newsletter, the cattle practise, All of our webinars and also reduced rates for all of our CPD. We represent you on a national level, and you've got access to all of our forums. But what I would say right now is this is absolutely free.

So hopefully, by the fact you're listening to the webinar, it already means that, you've logged on and you've registered for access to all of these resources. This is going to continue until the end of July, at which point we'll review it and depending on what's happening, with the current pandemic situation, this may be extended, but use this time to really find out, what BCVA can do for you as a student. Other ways that you can get involved is by stewarding at Congress.

I stewarded for a number of years as a student, and still now, many of the people I interact with and work with, I first met as a student, when I was stewarding at Congress. Currently, Congress is still set to go ahead, between the 22nd and 24th of October this year. Steward applications are still open, and they're open until the 1st of May.

So please take a, Keep an ear out, and an eye out for, for these adverts and and contact us by emailing us at congress [email protected] and tell us why you want to be a steward in 100 words or less.

This will come up at the end of the the presentation as well. Another thing that we started this year is we've got our new BCVA students reps. I know a lot of them are listening, tonight.

And our aim is here, by having an individual rep in each, each, each university, is that BCVA is much more accessible to our students. We want to be doing more for you. And, unfortunately, we had, we were planning to have lots and lots of face to face clinical clubs, but we hope that by offering these monthly virtual clinical clubs, we can still support you to some degree and by offering our, our membership as well.

So if you've got any queries about about BCVA you want to find out more, then these guys on the screen are the ones to get in contact with. So throughout tonight, I want to keep it quite nice and interactive. I want to hear some from, from you as to, to what you think about some of the things we're talking about.

So you'll see here on your screen that, you will, a poll will have popped up. And what I want you to do is answer the question as to which vet school is the best. So we've got A, Bristol, B Cambridge, C Dublin, D Edinburgh.

E Glasgow, F Liverpool, G London, 8, Nottingham, and I, Surrey. Which one's the best? There there you go.

I'll just give it another 10 seconds just for those last couple of people to vote. OK, I think that's pretty much all of you voted now. I'll end it there.

And it looks like, Sara, that RVC is the, best, vet school. Well, I, I'm not gonna dispute that. So, we've got 21, 21% of people have said Bristol.

Brilliant. 4% have said Cambridge, 6% Dublin, 4% Edinburgh, 15% Glasgow, 6% Liverpool, 38% London, 4% Nottingham, and 2% Surrey. Brilliant.

OK, well, I'm not gonna argue with RVC or Bristol as I attended both of those, and indeed Nottingham and Liverpool as well. So, that's brilliant. So that's just how these poll questions are gonna run as we go through the course of, this evening.

So let's go on to the main the main topic of tonight. And er that's digital dermatitis. So let's start with thinking about why we actually need to control it.

So when it comes to the scale of DD across our our dairy herds in the UK we don't really know how many farms have DD cos there's no formal recording. However, estimates really are that we've got over 90% of UK herds affected. I would say actually this is probably much, much higher and it's probably over 90 95% of herds now.

When we did the ALA workshops all across the country. The areas that didn't tend to have DD or many farms with DD tended to be on the periphery. So over in Norfolk, Isle of Wight, and further up in Scotland too.

So it really is unusual if a herd doesn't have DD. When it comes to how many cows on those individual farms can have DD, well over 50% of cows can be infected sometimes. Now it doesn't mean that they may, they necessarily all look like the photograph that you can see there, but certainly over 50% of cows can have the infection.

And more and more we're not just seeing it in the milking cows, but we're seeing in dry cows and increasingly young stock as well. And that's a major concern, which is why what I something I'll I'll focus on later on, in the presentation. So let's talk about what DD actually is.

So let's start with a few facts or fictions. So again, these are gonna be exactly the same as the previous poll question. I just want you to answer whether it's a fact or B fiction.

So first of all, DD is a bacterial infection of the skin. Is that fact or is that fiction? Don't worry, you're not gonna get named as shamed if you get it wrong, so.

You'll be fine. OK, just give me 10 more seconds for those last few to make up their mind which way they're gonna vote. I can see a few of you haven't voted yet, come on.

Mhm. OK, and we'll end it there. That's most of you voted.

So, 92% of you have said it's a fact, and 8% of you have said it's fiction. OK. I will be answering these in the next couple of slides.

Do you think that DD can be eradicated from a herd? So is that a fact we can eradicate DD from a herd, and let's put this into perspective, a commercial herd which we're dealing with to, to try and control DD. Do you think we can eradicate it from the herd?

Is that fact or is that fiction? It's closest one? Oh, started off quite strongly one way, but it swung the other way.

Peer pressure. OK, I'll end it there if no one else is gonna vote. OK, so we started off quite heavily towards fact but ended up with 43% of said fact and 57% have said fiction.

Oh, interesting. OK. The third fact or fiction is all DD lesions are red and painful.

So is that fact, is every single DD lesion red and painful? Or is that fiction? Oh, this looks unanimous, this 10.

OK. Everyone was straight off the mark with this one, no hanging around. OK, OK, we scanned it there.

And we've had 100% of people have said fiction. Well, hey. Excellent.

OK. Final fact or fiction, the cow is the biggest DD reservoir on the farm. So the cow herself.

Is the biggest DD reservoir on the farm? Do you think that's fact, or is it fiction? Is it somewhere else that actually is the main reservoir of infection on the farm?

OK, just give me another 10 seconds. You're getting much quicker off the mark voting at the moment. It started off slowly, but you're getting quicker now.

OK, and just we'll end it there. And so we have 21% of said fact and 79% have said fiction. OK, brilliant.

Right, well, we're gonna answer some of those in the following slides. So, Let's think about what DD actually is. And it is a bacterial infection.

So 92% of you were correct there. So it's a bacterial infection which, belongs to the group of bacteria called spirochetes. And this means they're spiral in shape, and that allows DD to sort of dig down deep within the, the foot through the skin.

The specific species are called the trepanines, and there's actually 3 different species that we find in, in DD lesions. Now, the lesions, which tend to be More severe, have all of these three species in. But sometimes what we find is that farms only have 1 or 2 species on the farm.

And this is why sometimes they can buy in cattle, and despite having DD, they can see a flare up because they're bringing in a different species. They're, certainly are, species within those three that are more severe than others, but I think now we tend to find 3 species on most farms that are infected. In terms of the bacteria themselves, they're very, very active.

They don't just sit around waiting for a host. They're actually quite active. They're mobile, and they're invasive, and they can move very quite rapidly, in a wet environment.

So if you consider how dairy cows and what the floors are like, that can allow a medium for these, bacteria to swim along to. And the slides that you see there on the, the right, the images, and that's actually what the DD looks like, under a microscope. So these long spiral bacteria, they can either be singular, so they're sort of on the surface of the foot.

And then they start clubbing together. And you can see on the far right hand picture, you've got lots and lots of DD bacteria all together, clubbing together, and then that black blob at the bottom or the dark blob is actually a little cyst. Now, if you cut through that, you've still got live bacteria in there.

And this is one of the big step forwards that we made in terms of understanding DD. Because people would have DD on a petri dish in the lab. Do something to it, to try and kill it.

It would form all these little black balls, so you think you've killed it, but actually, if you cut into them, inside it's still living. And that's given us a lot of information in terms of how we understand DD behaving on the farm, because it's certainly not alive or dead, but it actually has this ability to insist. The other thing about DD is it absolutely loves moisture and warmth.

So again, if you think about a cow's foot and the infections on the back of the foot, that creates a lovely moist, warm environment for the DD to thrive. And we'll come on to other areas where we can find it as well. One of the things we found is, though, that it doesn't like oxygen.

So if it's exposed to oxygen, it tends to form these cysts. It used to be that we, we thought it was completely intolerant of oxygen, but now research from Liverpool University has been finding that it's actually more a tolerant. So it's, it's surviving longer in, in oxygenated environments than we previously thought.

So again, it's a bug that's constantly evolving, and we're constantly finding out new things about it. One of the things that is quite frustrating when it comes to research is that DD is incredibly easy to spread on the farm. Like I said earlier, more than 50% of cows in one herd can have DD.

Yet, when it comes to the lab, it tends to be quite a fragile bacteria and quite easy to kill off. So again, that's made our understanding and our, expansion of our knowledge base around DD quite, quite difficult. However, we have, in the last few years, come on.

Sort of quite well in terms of understanding how it behaves. So in terms of we think about where DD lives, well, it lives on the cow, specifically these digital dermatitis lesions. So the DD is actually affecting the skin.

It's a skin disease. It's not affecting the horn of the foot, it's not affecting the nail structure, it's affecting the skin. So we don't tend to find it, actually just invading horn.

We tend to find it invading the skin. And these are the areas around the foot that we would typically see it. Most of the time it's at the back of the foot between the bows of the heel, like you see in these two photographs here, too, particularly nasty digital dermatitis lesions.

Other places we find it is up in between the interdigital cleft, or we sometimes see it on the front of the foot as well. And you can see from these histology slides on the left hand side, this is the route that DD takes to get into the foot. So it'll tend to track down the hair follicle, because that's a weak opening in the skin.

So it's very, very invasive, it goes deep within the foot and that's where it tends to tends to live. In terms of other places that it can live on the, on the cow, where, where we also find it, we also find it as an opportunistic, infection in other claw horn lesions. So this photograph here, you can see is a really nasty white line lesion.

If you take off the horn of the black area underneath, you've got the exposed quick or corum, and that's super infected with DD as well. Again, a really nice moist, warm environment for the DD to thrive. This one's a much more severe case.

So this is the hind foot of a cow. And what you see exposed there, so the red area in the centre of the soul, that's actually exposed corium. So exposed quick that's surrounding the pedal bone.

And what, again, what's happened is that the DD hasn't actually caused that lesion. But there's been a lesion there to begin with. I think this one started off as a toe ulcer.

The DD's gone in and it's infected that tissue underneath. So again, it's not causing these lesions, it's just coming in once they've already happened and complicating them with a, superimposed digital dermatitis infection. We also find them in hock lesions as well.

We've got damaged skin there. It allows the DD to go in. It's also now associated with ischemic teat necrosis.

This is some work that was done through the RVC. This photograph here of the other just shows that this, this heifer is actually missing, one of her teats because what's happening is that the, the DD infection is getting onto the teats. And it's causing a loss of blood supply.

It's incredibly painful for the animal. And actually, in some situations such as this, they actually just bite off the teat. So, again, we're not quite sure whether DD's causing this or something else.

It's coming in as a secondary infection, but certainly, we're tending to find DD everywhere. And, and, other sores as well at the front of the, the udder. They've been around way, way longer than DD has been reported.

But again, it's a nice environment for Didi to thrive. If you think about how the cow lies, if she lies with her foot right up underneath that udder, it's allowing that DD to jump off the foot and into that udders sore, and then they just become much, much more severe. So when we see these problems on farm, it's not necessarily that DD's caused them, but it indicates that probably we've got an uncontrolled DD problem and we need to get on top of that in order to try and prevent some of these lesions from forming.

So we find it on the feet, find it elsewhere on the cow as well. And then we also find it, on other animals. So cod and sheep, contagious ovine digital dermatitis, worked by Liverpool, which has done the genomic sequencing, they found that as far as they're able to tell, it's the same bacteria.

So again, major cause of lameness in sheep, and we've got to consider this when we're talking, when we're considering sort of co-grazing of of cattle and sheep. What about the environment? So, remember, I asked you where, where the main reservoir of infection was.

And 79% said fiction for the cow being the main source of res reservoir of infection, and 21% said it was the cow. Well, it is the cow. We did typically think of the environment, particularly slurry being the main reservoir of infection.

But again, work from Liverpool has shown that actually in the environment, it doesn't survive for too long, so at 17 degrees, DD will survive in slurry for around 24 hours. So whereas before, our advice might have been, well, we get it more at housing, it must be in the sheds. Actually, the cows are bringing it in on their feet, and then they're infecting the environment in the shed, and then it's able to sustain infection in the herd.

So, although it can live in in slurry for a short period of time, as long as we stop the feeding of that environment, we stop the the reservoir being continued, then actually we can help reduce our transmission. But one thing about the environment and slurry is that slurry is really irritant to the feet. You'll know yourself, if you've done a carving or a lambing, and, you've got ammonia on your skin, it's really, really irritant.

And that's what's happening to the feet of the cow, because you've got a lot of ammonia in slurry. So, slurry, it acts as a transmission route, albeit it can be a short-term transmission route because it's not gonna survive in there for a huge period of time. It also causes the damage to the skin, that is required for Didi to take hold.

You see the situation on the left hand side here. That's a massive tidal wave of slurry coming down the shed. And you can see the cow that's standing at the feed barrier where the, the scraper has just passed through, and she's got real slurry boots on there.

So hygiene is still really important, but it's not actually the reservoir of infection, it's actually the cow herself. So let's try and answer the question, the fact or fiction, are all DD lesions red and painful? So, 0%, so 0% said that was fact and 100% said fiction, which is really, really great, because that indicates that, you know, you're, you all understand that actually it's not just always the case that these lesions are like some of the photographs that I've shown you previously.

So, let's start off with thinking about the cycle of infection, because that's quite important when it comes to, understanding really how our control measures are going to work. So, let's think of this, we start off with a nice uninfected foot. So here in the photograph, you can see that we've got nice clear skin in the interdigital space.

Now, if we've got, say, 100 cows in the herd, well, 100% of those herd, those cows are going to be infected, are going to come into contact with DD. But not all of them do. And there's a number of reasons why some cows might not, come down with digital dermatitis and others will.

Individual cow factors such as stress. Have we got an animal that's more stressed? Is she more high producing?

Has she just carved? Heifers are more prone to stress as well, coming into a new herd. Factors such as low poor foot conformation and low heel height, which means that, the back of the heel is constantly in that slurry, and constantly irritating that skin.

So let's assume that a cow is, one of those that's at risk of getting DD. So we have to have some, some skin damage, for, for DD to take hold. And if that is in place, then what happens is we end up with a lesion developing.

Now, this is what I would call an active lesion. I spend a lot of my time talking to farmers, and, and when you start talking about the different stages, the end stages of DD, they get a little bit confused and think you. Starting talking about motorways.

So, I try to simplify it for them. So, when I'm talking about M1 and M2 lesions, I'm talking about active lesions. So, these are red, red raw lesions where the skin is broken, they're painful to the cow, although she may not be lame.

And, these are our sort of our active, active lesions. They can be, Red like that, they can look gra gra, I can't say the word. Like granulomas as well.

So they can have very many, many different guises. But one of the, one of the, well, I think I'll save that for the poll question later, actually, but one of the things we need to consider is actually how long it takes for these cows to develop these lesions as well. And that's quite important when we're talking about, control.

So, I mentioned that cows need to have some sort of skin damage to, to allow DD to take hold. So when they were trying to do some research, a guy called Arturo Gomez from Wisconsin University, he did his DD, he did his PhD on, on DD. And he tried to create DD in a lab situation, and he found it really, really difficult.

So, this is a research situation where he had a group of steers, in the facility there. And he found that if he took pure DD, so this isn't DD diluted in slurry, but this is pure DD bacteria. If you put that just on the back of the skin, on the skin, on the backs of the heels, he didn't get DD.

He then cut into the skin and put DD into the lesion, into the incisions, and still, he didn't get DD. But what he did to get DD was this process here. So, first of all, you can see that on the first photograph on the left hand side, the arrows are where he inoculated the skin with the DD bacteria.

Then he wrapped it in the second photograph, he wrapped it in some cotton wool. He soaked that. He put some cling film-like substance over the top.

He wrapped it again, soaked it, put a wrap, a further bandage on top. Then he put it in a rubber boot and gaffer taped it. And within a week, he found that he had really nice DD lesions developing.

And that shows the amount of skin damage that's required for DD to, to take hold. So what the process that's happening here is, it's actually maceration. So the, it's like if you, if you spend hours lying in the bath or you go for a really long swim, you notice that your skin becomes quite wrinkly, it becomes much, much more weakened.

And this is what's happening here is that all the skin cells are pulling apart a little bit, and it's allowing the DD to go in. But the key crucial thing is that unless we have that damage, we're unlikely to actually just get DD on its own. So it's a combination of exposure to the bacteria, but also, the right conditions on the foot for DD to be able to enter the skin and cause a problem.

So we've got cows with active lesions, not all of them are lame, and that becomes a problem when we, we talk about identifying these cows, and we'll come on to that later. Now, even if we don't do anything with these cows, they will go through into the next stage, which is the healing stage. So this would be our, our M3 stage, according to the Wisconsin scoring system that Dorte Doer, developed.

So this is where you can see from the photograph here we've got a thick black scab forming over the top. And these are no longer painful lesions. So you can see it's a nice thick, consistent black scab.

So that's what I would classify as a healing lesion. Now, note, it's not a healed lesion, cause a healed would imply that actually it's cured, but we don't tend to find that these on a farm situation actually go back to the uninfected stage. We sometimes see on farms that are using, corrosive foot baths, so formalin and copper sulphate.

That we see this type of lesion quite commonly, and that's where we have cows that have had active lesions going through the foot bath, forming a scab like you see here on this, in this new photograph on the left-hand side. And actually, if you pull that scab off, you can see that we've still got active DD underneath there. So where these cows, when they move forward into the healing stage, where they go from there is actually quite crucial in terms of determining, how well our control is.

So what happens once that scab comes off? Well, like we have here where the scab comes off, it can actually revert back to active. So we get M3 bouncing back to to active M1 or M2, so that's the, why the arrow is going in both directions there.

Or the scab comes off and we're left with some scar tissue on that, that back of the heel. And this is what we call an M4 lesion. So we've got no breaking of the skin there.

We've got no painful focus of infection, but we have got changes in the, in the foot. Now, that's not a cow that no longer has DD. She's got DD that's insisted deep within the foot.

And these are actually the reservoir of infection in the herd. So you can have quite a high proportion of the herd with these type of lesions. And the DD is sat deep within the foot, waiting for the opportunity to come back.

Again, if they're going through a corrosive irritant foot bath, this is what we see. So, this photograph here just shows a lot of excess skin. So you've got a, you've got skin that's been damaged and is, is being irritated.

And, here you'll just see that we've got lots of excessive skin growth, and that's an indication that we've got some aggressive foot bathing reagent that's being, being used. So, as I said, if these lesions aren't controlled, then it goes through the next stage, which is our recurring stage. You can see here the big photograph just shows where we've got this thickened horseshoe ring of skin around the back of the heel, and the start of a new lesion that's coming forward just there, and that's a, a close up on the smaller photograph.

So these are cows that have had DD before, but because control measures aren't in place. The DD is allowed to come back and we're getting reinfection. And when we get outbreaks in herds, it doesn't tend to be new cows getting infected, it tends to be old cases recurring.

And the majority of the reservoir of infection in the herd is actually from these, these dormant, dormant lesions. So where farms aren't controlling these, and we'll come on to control later, that's why we tend to see these waves of infection, is these cows work their way through the cycle and then they recur and they become active again. So in terms of you all thought that DD lesions weren't always red and painful and and this is why, because no matter what stage of the cycle she is, she's still classified as having DD but they're not all red active lesions.

So going back to our facts and fictions. You're right, DD is a bacterial infection of the skin. Now can it be eradicated from the herd, you were split here.

Now, it can't really be commercially. You could eradicate it from the herd, but you'd have to get rid of every single animal that had DD. And if we're talking about an endemically affected herd, some herds are between 50 and 90% of cows that have got DD.

So, really, that's got to be a fiction, because we cannot eradicate it from a herd unless we start hunting down all of these cows with dormant lesions and culling them out, which isn't really that practical in a commercial situation. You will agree that that was fiction for all DD lesions being red and painful, and the cow is the biggest DD reservoir on the farm. Well, that's fact, because although the reservoir of infection can exist in the environment, actually, that's quite short, short-lived, whereas it's actually the cows that, that are harbouring the DD bacteria, and they're the ones that are drivers for infection.

So moving on then to trying to put together a structured protocol for DD control. So, we don't know everything about DD, but we know enough about how it works that we can actually put together a control programme. And like I said earlier, this is a programme that can be rolled out on, on any, on any farm.

It doesn't matter on its management system, doesn't matter whether it's housed or grazing. This protocol, will help reduce and control DD. So the first step of the protocol is obviously to identify the cows that are infected.

I said before that not all cows are lame with DD, so that presents a challenge, because typically, we, we mobility school cows to identify those that are lame or have problems, but this doesn't quite work for DD, not all cases. Then we need to do what we call a blitz treatment. So a lot of farmers already will be treating cows.

So say the cow on the right hand photograph, he'll notice, or she'll notice her in the parlour, they'll treat them. But actually, if they're just picking up cows when they're severely infected and they're treating them ad hoc, we're constantly going to be feeding the environment. So if you think about any active lesion, it's gonna be constantly feeding the environment with infection.

So what we need to do is we need to blitz treat them all, and we need to dampen down that infection of the environment. Then we obviously need to prevent it, so once we've treated everything, we obviously need to prevent it from, from coming back and prevent those recurrences. And then obviously we need to have an ongoing monitoring programme to make sure that all the actions that we've put in place are working.

And my target, if we put this plan in place, is that we have basically 1, less than 1 active or recurring case per 100 cows per month. So less than 1 treated case by the farmer per month. And that's a really, really low, threshold to set.

However, it is achievable. So if you talk to a lot of others in the field of lameness around the world, they set around a 5% threshold for active lesions. However, from my work that I've been doing on farms.

Once we're up at around 5%, actually, we've got a lot of DD that, that needs controlling. Whereas if we really hit it hard to begin with, then we can reduce it to these really, really low levels. By the time the farmer starts treating that couple of extra cows a month, it's not too much of a, a problem to actually pull that back and back to that, that level of control.

So moving on to these in a little bit more detail, let's talk about identification first. So, a poll question. How long on average does it take from when a cow, an uninfected cow, first starts showing signs?

I'll just move that out of the ways. First starts showing, signs of DD. So when the skin is first broken and DD is still, first starting to cause that lesion, how long until she goes lame?

Is it A, around a week, so a week from when she starts getting a lesion to when she goes lame? Is it around a month, so 30 days, is it 50 days, is it 100 days, or is it more than 100 days? So how long from when they first start developing a DD lesion until they go lame?

OK. I'll just give you 10 more seconds. I know there's a few of you thinking about that one.

OK. Last couple there and I'll just end the polling. So we have 16% have said 7 days, 56% have said 30 days, 20% have said 50 days, 4% 100 days, and 4% more than 100 days.

OK, so those of you that selected E, more than 100 days are right. So a study that was done in the States, looking at the development of lesions, found that on average, it was 133 days from when the skin was first broken and DD infection was first found on the skin until the cow went lame. So on average, 4 months.

And not all cows went lame, and certainly when I go out mobility score and DD score at the same time. I only find actually that about 50% of cows with active lesions are visibly lame. So that presents a huge problem for two reasons.

One identification, but then also the fact that for on average 4 months, that cow has got DD. She's walking around the herd, she's putting other uninfected animals at risk, yet she hasn't been treated yet because she hasn't gone lame. There was one animal that actually took nearly 600 days before she went lame.

So in that 600 days, she hasn't been treated, and she's putting other cows at risk. So well done to those of you who chose over 100 days. And this was some, oh, there we go.

OK. So, this is cow 144 in the video here now, you'll get to know cow 144 very well through the, through the rest of the presentation. She's a cow that I always show farmers and say, Is she lame or not?

Now, she, you can see, is a pretty headstrong cow. She's giving us a good look there, saying, What are you looking at? If you consider the mobility scoring, system, then she is striding out.

She's got a nice flat back, she's looking where she's going, and she's going forward. But if you look closely at that back left foot, You can see she's not fully putting her weight on it, and she's just hopping a little bit on that foot. And she has got a DD lesion, and you'll see it in the next slide.

But for actually a lot of cows that have DD, they don't, they don't show any signs of a mobility score. And there is a crucial need, when we're tackling DD, that we need to, do need to identify all infected cows, because if we're identifying them off a mobility score, we're missing 50% of them. And we do really need to find them all if our programme is going to work.

So we've got this long lag time to lameness that I discussed after the previous poll question. So that's really a massive missed opportunity. So really the most effective way to to look for these lesions is through parlour scoring.

So what we need to do here, you'll see that same cow 144. This is her as she walked into the parlour, literally straight away after we'd taken that video. You can see here, she's got a mucky foot.

Now, we can't see whether she's got DD there or not. So we've got to wash them off. You'll see the farmer here, Hopkin, you'll meet him again later.

He's just washing off all of the feet here of the cows. And, once he's washed them off, he's actually going with a torch. You can also use a fish slice, just to help visualise these lesions under the back of the foot.

But, you know, now that we've washed off cow 144's back left foot, you can really see that there's a quite a big, a big lesion there. So, we need to go through the herd, wash off all the feet, and mark up all the cows that have got DD. You'll see Hopkin here with a marker in his right hand, and he's actually visibly marking the cows that have DD.

I find this is really, really useful. So, when I go out and do parlour scores, I actually spray the back of the leg from the hock right down to the dew claws of the. Cows that have, DD lesions.

And this is a real eye opener for farmers as well, because they say, God, I've got loads of cows with DD. If I hand them a list, it's not as visual. It doesn't impact them as much.

I do note down which cows have DD, as well, but visually, if I'm wanting farmers to follow up on treatment, and then actually visibly marking the individual cows is much, much more effective. So what about for dry cows, young stock, or robot herds? Well, you can see here, this is a cow at the feed barrier here on the left hand side, and this is just a video taking, looking at cows at the feed barrier.

And you can see it is really, really difficult. The feet here in this video are quite dirty, so it becomes much, much more difficult to actually identify cows that have DD. Obviously, if a cow is just slightly raising her foot, then it gives you an indication that she might be lame on that foot and you can, you can, Give her a closer look.

I recently did a study as part of the Welsh government project that, on a robot farm with a DD problem, with the issue that we couldn't identify cows easily, and we scored all of the cows at the feed barrier, 180 cows, and then we ran them through the crush the next day. And we were missing, about 50% of cows that had active lesions at the feed barrier. So we, we, so doing that at the feed barrier can be a useful tool, but we have to accept actually that we're going to miss some cows.

And so maybe we have to increase our sensitivity, when we're identifying them at the, at the feed barrier. And certainly running them through a foot bath before they come out and you're scoring them does help clean off the feet as well. So in terms of how the same lesion looks, this is again, CA 144, her back left foot, and these, these three photographs here were taken within the space of half an hour.

So, that's her at the feed barrier, in the parlour, and then in the crush. You can see that, that's quite a nasty lesion that she has there. And just think back, she wasn't actually hugely lame.

Yes, she was lame, she's definite score too, on the HDB score on that back left foot, but she's not as lame as you would think she would be, given her, her lesion. But I think that sort of reflects the sort of cow she is. So, once we've identified all of the cows that have active and recurring lesions, then we need to, to treat them all.

And this is where the blitz treatment comes in. So, let's think again. Let's think about the rationale behind the Blitz treatment.

So, just to test you again, where's the main DD reservoir on the farm? Is it A, the slurry? Is it B, the DD lesions themselves?

Is it C, the cow's gut, because we do get semtreponema in the cow's gut, or is it D out in the fields? So where do you think it is? OK, so I'll just give you 10 more seconds.

I see most of you have answered there. I'm sure the people who didn't get, don't get this right, are are the ones who joined late. We'll give them the benefit of the doubt, rather than if they weren't listening, shall we?

We, we don't know, we don't know who's answered what, just to let you know, and none of this gets fed back to any university. So it's all completely anonymous. So don't worry.

Oh in there. OK, so 4% have said the slurry, 84% have said the lesions, 4% have said the cow's gut, and 8% have said fields. OK.

So the answer is B, the cow's foot. So that's because these are where all the infections are sitting. Even if a cow doesn't have a red raw lesion, she's still gonna have DD sat deep within the foot.

It's only going to survive in the slurry for a short period of time, so around 24 hours, which is what I said earlier, at around 17 degrees. So, Although the slurry can act as a reservoir, it's a very short term reservoir, whereas it's actually the infected cows that are the main source of DD within the herd. So think of it as like a contagious mastitis.

Although the parlour can pass on Staph aureus infection, it's actually the cow that is, the main reservoir of that bacteria in the herd. So, let's just look into the rationale behind this Blitz treatment. So, as I said, the infected cow is the main reservoir.

She's the main risk to uninfected cows. If you consider that they can have around 4 months before they go lame with this, in that time, she can be spreading it to other cows. So the slurry is without doubt a potential transmission route, but it is a short term reservoir of infection.

So when we have just ad hoc treatment, which is what a lot of farmers tend to do as they see or smell DD lesions, it means that we get this constant maintenance of the environmental reservoir. So the idea behind the blitz approach is that we treat all of the cows with active or recurring lesions at the same time. If we treat all of them at the same time, what we then do is we reduce the amount of DD that is then being shed into the environment from these active cows.

We then after a couple of days, because DD won't survive in slurry for a huge period of time, what we're then doing is reducing the environmental reservoir. So then over time, it actually means that our preventative measures are not overwhelmed by the huge amount that's being maintained in this environmental reservoir through all of these active infections. So, cow 144, she comes into your crush, you lift up that lesion.

What are we gonna treat it with? So we're talking about treating all of the cows that have got infected lesions. What are we gonna treat them with?

Is it A, a topical copper sulphate powder or paste? Is it B, a topical antibiotic powder, C, a salicylic acid powder, D, topical antibiotic spray, E injectable antibiotic, or F, should we be treating them with something else? So what have you seen in practise being used?

Oh, it's up now. So is it a topical copper sulphate, powder or paste, so that's like a blue paste that you would see. Cows tend to kick a little bit after it.

A topical antibiotic powder, so Lincain, erythromycin. Licopectin, salicylic acid powder, so that's like an aspirin powder, a topical antibiotic spray, so that's your blue, your blue sprays, green sprays, an injectable antibiotic, or is it something else? What should we be treating these animals with?

OK, just give the last couple of years a chance to vote. And we'll end it there. OK, a bit of a spread across the board for this one.

So 25% have said A, 12% have said B. 2% have said C. 37% have said they.

20% have said E and 4% have said F. Brilliant. OK.

So the majority have it here, and I'll just go through, some of the reasons why we might not be considering, some of those other options there. So, once we've put our topical treatment on, should we then be bandaging these feet? So, once you've used your treatment of choice from the last slide, would you be putting a bandage on this?

Yes, A for yes, and B for no. OK, so nearly all voted. And we'll end it there.

But the landslides want 12% have said yes, and 88% have said no. OK. Brilliant.

OK, so we're gonna go through some of the evidence base, behind these now. So, before we consider what we should be using, let's just consider what our aims are here. So, we've got a cow that's come in, she's lame, she's sore.

So, we obviously want to rapidly reduce the infection levels in the environment, cause she's shedding DD out into the environment, she's putting other cows at risk. At the individual cow level, we obviously want to resolve this infection. Now, when we look at that infection, we've got DD in there, but we've also got loads of other secondary infection.

Now it's really unlikely that in a case like this, we're actually gonna be able to cure the cow. We think that the DD, it comes onto the surface of the skin and it starts insisting and burrowing deep, deep within the skin quite quickly. So unless we catch them really, really early, it's unlikely that we're actually gonna catch them at the stage where we can completely cure them.

So we sort of assume that once a cow's had infection, once that she's got it, she's got it for life, it's a life infection. So what we're really talking about here is resolving the secondary infection of that lesion. We obviously need to do this by minimising the pain to the cow.

We don't want to be causing pain, in terms of our treatment, or certainly want to be causing the minimal amount of pain when it comes to our treatment. We want to reduce the risk of further insisting of bacteria. So we can consider we've already got bacteria insisting in that foot, but we want to reduce further insisting of that bacteria.

So we don't want to use anything that's actually gonna cause those bacteria to go deeper within the skin. And of course, we need to be using antimicrobials responsibly as well. So one thing we could do, because say for instance, we're doing this programme on a herd, we've got 100 cows, and we've got 50 that have active lesions that need treating.

Well, surely we can just put them through an antibiotic foot bath? Absolutely not. We cannot justify these anymore.

So this has been, a mainstay of control on a lot of herds previously, but we absolutely cannot justify treating a whole herd with antibiotic foot baths anymore. And there's a number of reasons for this. Firstly, it's prophylactic use.

You, I'm sure that you've all heard about the drive towards more selective dry cow therapy. So if a herd is doing selected dry cow therapy, then it doesn't make sense to use an antibiotic footbath, because they are treating every single animal in that herd with antibiotics, even though the vast proportion of them won't actually need them. Secondly, there's no licenced products.

So all of these products that might be used in an antibiotic foot bath have a 7 day milk withhold. Non-negotiable, we cannot be, advising that these are used. Disposal is a concern.

If you think about this amount of antibiotic being mixed mixed up in a foot bath, where's that gonna go afterwards? So we've got environmental contamination concerns. The other thing now is there's this big drive to reducing antimicrobial use.

And some research that was done at, Nottingham University by the herd Health group there, found that farms that were using a monthly antibiotic footbath were considerably adding to their overall antibiotic usage on farm. In fact, it was nearly taking up all of the allowance. So it's really, really important that, we look to reduce antimicrobial use and to make sure that we are respecting, The guidelines.

So, if we're actually using a 3 day targeted approach, and we're treating 40 cases per 100 cow per year, actually, we're way down at less than 1 mg per kg, for this. So you can see actually, a targeted approach to treatment is much, much better in terms of antibiotic usage. So really now, antibiotic foot baths should definitely be a thing of the past, and not something that should be advised for treatments and certainly for control of digital dermatitis.

So what does that leave us with? Well, should we be going through and injecting all of the cows? Well, the jury is still really out on that.

There's load of the, of the papers that have been published on this, and there aren't that many, there's really ambiguous evidence as to whether this actually improves digital dermatitis or not. Does it achieve a bacteriological cure? Well, again, research would indicate that unless we're using a, a, a very long course, and by that I mean a course of several months long, then actually, it's unlikely to achieve a bacteriological cure.

So you would think that by injecting the cow, we would increase our likelihood, but we don't think that it does. A 3 day course of injection is not actually going to cure that cow. And another concern is that the products that have specific indication for digital dermatitis are 4th generation cephalosporins as well.

So obviously are critically important antibiotics. So at the moment for these cows, there isn't sufficient evidence to warrant exposing the entire cow to antibiotics, rather than just targeting treatment at the lesion and the foot. So, this brings us on to one of my favourite topics, which is bandages.

I do have quite a strong opinion on the, on the use of bandages. And this is, this is based on the evidence that we currently have. So, they're commonly used.

I see a lot of bandages on, on cows' feet, as I drive around farms. But for me, they have a number of disadvantages. So the photograph here, this is actually a herd that I visited in the States.

Digital dermatitis problem. This cow stood at the feed barrier, picking up her foot, very, very uncomfortable. Now, that bandage had gone on a week previously.

She'd been going through a formalin foot bath twice a day since. So formalin soaked into the bandage, it was burning the foot underneath. So that's one disadvantage.

The other disadvantage for the cow is that they can tighten, and they can cause some really, really nasty, Damage to the tendons, particularly if they're left on. So that for me, from the cow's perspective, are two quite considerable disadvantages. From the farmer's perspective, they're costly, and they're paying the backside to take off as well.

If you, if you ask farmers if they like taking off bandages, I've never met one that likes doing it. Yet, they all seem to love them being put on. So, for me, if we're using bandage, there's got to be a lot of positives that outweigh all those disadvantages.

So the research that we have at the moment was done by a group over in Minnesota, university, and they looked at 214 cows, half were treated with oxytetracycline powder and a bandage and half with oxytetracycline paste. And when they were looking at successful outcomes, these were lesions that had healed, they found no difference between the groups based on a successful outcome. So for me, there was no benefit there in terms of outcome, to warrant using a bandage.

So, I know more research is being done on bandages, but currently, for me, there's not enough evidence to warrant the extra risk for the cow and the extra cost to the farmer. Also, once the lesion's under a bandage, the farmer's not going to see it and may not be following up with the needed treatments. But perhaps more importantly, what's underneath the bandage?

So, let's just consider some of the things that might be put under the bandage. So, commonly caustic paste, so this would be a mixed up copper sulphate paste. That's really caustic.

If you stick that on the lesion, it's quite painful for the cow, they quite often kick around afterwards. Now, you might have what appears to be a healed lesion once you take that bandage off, but it, it's more of a corrosive action, on that lesion. And that can actually increase the risk of the DD further insisting into the, into the skin.

But it also damage the raw skin. Now if you consider that raw, that raw skin that's been exposed. That's actually damaged skin.

We don't want to further damage it by putting something caustic on it before it's actually trying to start healing itself. I'll just point out here that these caustic copper sulphate pastes are very different to sort of the, the copper collated copper, gels that you get. They're not as, as caustic.

So, for me, the caustic paste is something that we should be avoiding because it's a welfare issue if we're actually causing pain to the cows. The other thing that we see commonly used is unlicensed antibiotic powder. Again, it does work.

It's an antibiotic. It's treating the lesions. However, can we justify its use?

Well, no, there's a risk of milk contamination. So if we're putting antibiotic powder on the backs of the feet, we know that within 8 hours, 100% of lesions, 100% of teeth, sorry, will be contaminated with antitibiotics. So there is a real risk of milk contamination.

We also know that some of that antibiotic can be absorbed into the cow as well through the lesion, and then they're actually from the study that was done in, in Canada, they were finding, oxy tetracycline in the milk, and this was causing cows to fail at a certain degree as well. So, For me, there's too much of a bigger risk there when we have alternatives available to us. Again, 7 day milk withhold when any of these products are used.

So what does that lead us back to? Well, from all of the data, all of the research that's been done, it brings us back to our topical antibiotic spray. I tend to use angamycin, but there are many others out there that all contain, a licenced topical antibiotic.

And these really, they achieve all of our treatment aims in terms of they're gonna resolve the infection rapidly. We're not gonna cause undue harm to the cow, and we're not using anything that's too, too caustic. However, when I talk to farmers about blue spray, they do tend to say, Oh, it doesn't work so well.

But this is usually because repeated treatments aren't given. If you consider tubing a cow for mastotis, you need to give them a couple of days of treatment, and that's the same with DD. Some cows need one day of treatment, others might need, need more, and it'll depend on the severity of the lesion.

Sometimes it's also applied incorrectly, so if the cow walks in, she's got muck on the lesion and it's sprayed on top of the muck, well, it's not gonna work. So, really we need to be looking at making sure that these cows are treated and treated effectively. One big step forward in the treatment of these cows, is that obviously if we treat them in the crush, we're gonna get slightly higher success rate, but it's much, much more difficult for farmers to treat in the crush, so .

One step forward has been that red tractor standards now say that blue topical spray also antibiotic, spray can be used in the parlour. And this does make the blitz treatment much, much easier to do. So, for instance, if you're putting 80 cows through for treatment, it's much easier to do them in the parlour than it is, through the crush.

However, it's still got to be done safely to try and avoid a risk of contamination of milk. So, in terms of what the data points us to at the moment, it's still that topical antibiotic spray is the go to. And if we consider spraying a cow for, for 3 days with topical antibiotic spray, we're only using about 1 gramme of antibiotic.

So really, really low amount if you consider it, if you compare it to some of the other treatments such as injectable antibiotic and also antibiotic powders. It's also got no milk withhold, so we're safe in terms of residues. So this would be, this is just a video here showing cow 144 being treated.

So you can see there I've just simply washed off the foot, that's just in the bucket of, of clean water. They're cleaning out the interdigital space, making sure we've got all the muck there. And then I'm drying the lesion.

I'm being quite thorough in drying the lesion. Because I want to make sure that the antibiotic spray gets to the lesion itself, and any crud has been taken off the top. I've dried it there with gauze swabs.

I find that paper towel disintegrates and cotton wool tends to stick to the lesion. So, I've given it a good clean, giving it a good dry. I've not irritated it.

I've just dabbed it. I haven't scrubbed it. Then I've given it a thorough spray with the, with the antibiotic, and I've left it for 30 seconds before coming back and spraying again.

And it's important to get that into digital space when you're, you're treating them again. So, lift, wash, dry, spray, leave for 30 seconds, spray again. Now, that's put them, put through the crush.

That's where you're going to get your best, treatment result, cause you can wash the lesion effectively and you can also dry it very well. So, If we, if we're looking at doing it in the parlour, we have to accept that probably our success rate isn't going to be as high. So I even say to farmers, when we're doing a blitz treatment, mark up all the cows and put them through the crush for day one, and follow up in the parlour for days 2 and 3, or start off in the parlour, and any that aren't responding as you'd like to treatment, then put them through the crush.

So it's about working out what works, for the farmer. So in terms of the outcome of treatment, so you saw cow 144, she was a dry cow. We did her, this was, she was a cow that we treated as part of this ALA project.

And I was on the farm treating for 3 days, and we did the dry cows at the end of the 3 days, so I didn't actually go back to see her on day 2 and 3. I asked the farmer Hopkin, if he could follow up the treatments. And I just know that, that, the study that we did, we chose a farm, that was a very real farm in terms of real farmer, real cows, so that we, we would just basically test it in a real, a real life situation without going over the top in terms of gold standard, because we wanted to make sure it was, it was, realistic for all farmers to implement.

So you saw us treated her, treat me treat her in the crush on day one. I asked Hopting to go back on day 2 and day 3 to treat her. When I went back a week later and asked how many treatments she, he, he'd followed up, he hadn't given her any.

At least he was honest. He said, I've not given her any. So, I went back 7 days later, thinking that this lesion was going to look horrendous.

Unfortunately, she lifted up my crush, which weighs nearly 1 tonne, and set off across the yard and then jumped over a gate. So I decided to leave her be for that week. I went back 14 days later, lifted up the foot, and this is what I found.

So, you can see here that that lesion has, the skin has healed, and she's now what I would call a dormant lesion, because I, I, I'm not convinced that she's completely cured. We're going to have some DD insisted in there. And then our aim now is once we've treated her and she's through to that dormant stage is that we keep her there.

And I went back and checked her every 7 days, and you can see it 3 weeks after treatment. That's 6 weeks, and then several months later, we haven't actually had a recurrence of that lesion. So it shows that if we treat these animals and then we have the proper prevention in place, that actually we can stop that reoccurrence.

So that was one animal, we got away with it on her in terms of just one treatment cos she was a dry cow under less stress and there was less muck around in the dry cow shed. But what about some of the other animals? So, this is day one, a very small little lesion there.

That's what I would classify as an M1 lesion, because it's less than 2 centimetres in diameter. By day 2, so after one treatment, it started to dry up. And actually, by day 3, the scab had fallen off.

And the same with this animal, because we put better prevention in place, you can see that throughout 6 month period, she actually stayed, clean. She didn't, she didn't revert back at all. But I know what you're thinking, that's a very small lesion.

What about the worst one? So this is Heifer 222, she had that really horrible lesion that you saw before. This was day one.

After day two, you can still see that there's still a little bit of active area in the middle of the lesion. By day 3, still a small area here. And it took until day 10 for us to see her moving through that healing, to that healing stage where we had that thick black scab over the lesion.

It took a little while to come off, but you can see the lesion looking much, much better. However, by the 6 month review, we had this here. So this is just, again, it's a dormant lesion, but we've got lots of excess skin because the cows were going through a falling foot bath.

So again, no matter what the lesion is like, you can still treat it if you apply this approach, of lifting the feet up, cleaning off the lesion, and these repeated, treatments. Some cows, like I've shown will need one day, other cows will need much longer. So if we put that in the context of our cycle and what we're actually trying to do with treatment, well, we're treating all of those cows with active lesions.

And what we're trying to do is really drive them through that active stage to a dormant stage, because we can then do something with them. If we're very, very lucky and we catch these cows earlier, we might drive some of them back to uninfected, although from my experiences on farm, it's quite difficult to completely cure these cows. So once we've got to the stage where we've got these cows through to the dormant stage, what we can do then is we can control them much, much better.

So let's look at how we actually prevent those lesions coming back. Well, there's 3 different arms to prevention. We've got biosecurity, we've got hygiene, and we've got foot bathing.

So let's just look at those in a bit more detail. Biosecurity, absolutely. If they don't have DED, then we do not want it coming in the herd.

Everything that comes on the farm has got to be absolutely immaculate, sterilised, and, and disinfected, because we do not want to be bringing it on. The biggest risk Is buying cows in. So we've got cows that have got it on their feet, then they've got the potential to bring it into the herd.

One herd, which was naive to DD, they had it introduced because the, curl cow guy, he came, he unloaded some of the cattle from the lorry onto the yard to rearrange them and put them back in with some of the cattle from the farm as well. And that's how Didi got onto the farm. Slurry tankers are a concern as well, particularly where we've got these long umbilical pipes.

So, we need to make sure that we don't have DD on the farm, that, we keep it out. But also, we need to think also about different groups within the farm. So it's not only biosecurity between farms, but also to biosecurity within farm.

So if, if say, for instance, we don't have DD and the heifers, we need to make sure, think very, very carefully about how we manage those two groups. If you're using, the same scraper tractor for heifers and cows, that's a risk, obviously, because it can be, transmitted through the slurry. But also, think about when we're bringing all of these animals together and we're stressing them out.

Perhaps with TB testing. We start with the cows first, we bring them through the collecting, the handling system. They're all mucky because they're stressed, and then we're bringing the heifers through.

So just think about all these different risk factors of how it can be spreading around the farm. Hygiene is our next strand, and that's really, really crucial. Obviously, cleanliness and DD are directly related.

We know that the dirtier the feet, the more likely it is that the herd will have DD and more DD. So slurry management is really crucial, and we need to look at where the high risk areas are. So, is it, for instance, the automatic scrapers?

Automatic scrapers don't definitely mean that you'll have a DD problem. I've got farms with automatic scrapers that don't have DD and farms that do. And it's not so much about how often the DD scrape, the scrapers are sent off, but more about when.

So for instance, you don't want them going off when the cows are standing, eating. So it's about timing them to times of least cow flow in that area. If you've got this sort of situation here where the scrapers are just dumping it all on the crossover passageway, well, that's a real big concern as well.

So we need to look at how how that is managed to make sure that we reduce that, that, build up of the sawdust there. Other high risk areas might be the exit platform from the parlour, the collecting yard. It can be quite common that the collecting yard can be scraped once a day.

We really need to it to be scraped after every milking. So it's about looking at all the high risk areas and then dealing with those on the farm. But perhaps the most crucial aspect of prevention is foot bathing, cos we could have good hygiene in place, we could have good biosecurity in place, but if we've gone through a blitz treatment programme, we don't have foot bathing in place, we are most likely to see a recurrence of infection.

When it comes to who we should be foot bathing, well, we need to foot bath all at risk groups. So we've got Didi in the milking herd, absolutely we need to do the milkers, but we also need to do the dry cows. In farms, we tend to find big flare-ups after calving if we haven't got a good dry cow foot bathing programme in place.

And if we've got it in the heifers, then yes, we definitely need to foot bath the heifers. If you think about how long it takes for DD to develop, well, it was around 4 months. So for instance, if you're seeing DD at 15 months, we need to look back to what's happening around 11 months and start foot bathing then.

Just looking at a little bit more about why it's so important that we control DD and our heifers. This is some, research that was done again by Arturo over in the States. And he followed heifers in one herd all the way from, service right the way through to first calving, and then through the first lactation as well.

And he was basically assessing how many cases of DD they had. So in heifers that didn't have any DD during the rearing period at all. Once they were into first lactation, only 4% of heifers went on to have DD in first lactation.

If they'd had one case during the rearing period, there's about a 37% chance that they would have a further case in lactation. Again, if they'd had more than one case in the rearing period, it increased again. So you can see how the what the impact of controlling DD and the heifer rearing period has on, Has on the the level of DD that you see in the milking herd.

So, if we don't control it in the heifers, but we control it in the milking herd, we just get flare-ups every time that heifers carve in and bring DD into the herd. So it's about looking at all of the groups of animals across the herd and controlling all of those. So looking at a bit about more about when and where we should be foot bathing, well, let's think about when, well, how often is this?

So. We need to be foot bathing as often as we need to control the farm. And there's no blueprint, for every single herd.

So, for instance, some herds might need to foot bath every single day or every single milking. Other herds might need to feed foot bath 3 times a week or twice a week. But certainly, the more DD that is on the farm and the dirtier the conditions, the more we need to foot bath.

We could go in with a gold standard approach of daily foot bathing. However, we have to look at the cost benefit as well. Great if we can incorporate it into the cow's normal routine.

So in the photograph here, this foot bath is just on the parlour exit. 1000, well, there's now nearly 2000 cows going through that exit race 3 times a day. So if you position it correctly in the normal cow's routine, then you can get really, really good cow flow going through the bath.

And we really want to limit disruption to cow flow because if we make it difficult for the cows, they muck more and that affects the effectiveness of the bath. One thing to know, if you've got it on the parlour exit and you're using formalin, just consider, what ventilation is like around, the foot bath. There's been talk of formalin being banned for a number of years, and I think it's possible that it will be banned in the future.

So we just need to consider health and safety aspects, and ventilation in the area that the foot bath is being used. So, Just to make sure you're all still listening, what, another poll question. What's the most important thing to put in the footpath?

Is it A, a disinfectant? Is it B, water, or is it C, something else? OK.

Just the three options there, disinfectant, water, or something else. Is that something else, whiskey, is it, or gin? Whatever you like.

OK, there's a few of you still left to vote. So if you just want to select A, B, or C. And then we'll close the pollies shortly.

OK, I think that's most of you now, so I'll just stop the poll in there. OK, so 24% have said disinfectant, 51% have said water, and 24% have said something else. Oh, OK.

So. Disinfectant, absolutely we have to have in the bath. Water, absolutely we have to have in the bath as well.

However, neither of those is the most important thing to put in the bath. Now, I don't know what the 24% of you who selected C thought was the most important thing, but hopefully, it was the cow's foot. Because if the cow's foot doesn't go in the foot bath, it doesn't matter what you've got in there, because it's not gonna be exposed to it.

So the most important thing to put in the foot bath is the cow's foot. So when it comes to foot bathing. Its role is in prevention, so that's why I've said a disinfectant.

It's not a treatment. We're looking to constantly constantly disinfect the feet to wash off the infection, before it gets, it can take hold. And crucially, we need to prevent new infections as well as prevent those old ones coming back.

But despite the fact that thousands of cows across the UK are foot bathed, really, really regularly, there is hardly any robust evidence behind how often we should foot bath, what we should be putting in it. Which is quite concerning. When we look at a lot of the studies that have been done, we can't really compare them because they're on different regimes.

And also, they, they're looking more at treatment rather than prevention, which is really what we're aiming for the footpath to do. In terms of products, a lot of the products out there, like I said, don't have a huge amount of robust evidence behind them. Also, when it comes to frequency and design, we've got some indication from some of the evidence in terms of what the best design is, and we'll come on to that, now.

But really, when it comes to foot bathing, we need more evidence there. If you want to do a full of have a, read a full evaluation of, all the foot bathing research that's being conducted and what needs to be done for us to get more robust evidence, then, Nick Bell did a, a complete review of this for the Catalanus conference in 2016, and, the proceedings from that con conference are free, and download off the Catalanus conference website. So I'd urge you to go and have a look at those.

So in terms of looking at the chemical that we can use, again, I've said there's little evidence behind the vast majority of chemicals and the focus has really been on treatment rather than prevention. As I said, it's difficult to compare studies, but when we look at all of the data available, they still really come back to copper sulphate and formalin being the two best options that we have. But still, we don't have conclusive proof, we just have anecdotal, evidence from, from the fact that they are used to control DD on, on several thousands of farms across the UK.

There are issues with both in terms of copper sulphate. We've got issues with it being spread on the land and copper build up. And when it comes to forming, obviously there's huge health and safety concerns from that too.

In terms of concentrations that we're recommending, around 5% for copper sulphate and for formalin, rather than going for 5 in 10%, which has been recommended previously, actually we're lowering that much further down to just a couple of percent now. So most of my farms will be using around 2.5% formalin, but using it more, more regularly.

Interestingly, the poultry guys use it at 1% for disinfectant. So in terms of design, this is really, really crucial because if we don't get the design right, then we're not gonna have an effective foot bath. So obviously we need to optimise the number of times that the foot goes in the foot bath solution.

We need to be maximising cow flow through it, whilst minimising contamination. Got to make it farmer friendly. It's got to be easy to empty and refill, but also its use has to be cost beneficial.

You could have the longest foot bath in the world and have, you know, a huge number of dunks, but if it's not cost beneficial to the farmer, then, we've got to look at, we've got to look at that aspect too. So another poll question for you. When we're considering foot bath design, how many dunks of each hind foot do we want in the solution?

Is it 1234, or as many as possible? What are we aiming for? How many dunks of each hind foot do we want in the solution?

OK. See lots of you voting. See if anyone else is gonna sway the votes.

It's one clear winner at the moment. Oh. OK, we'll end it there.

So, A is 2%, B is 21%, C is 21%, D is 6%, and E is 50%. So most people are saying as many as possible. Yeah, so ideally you want as many as possible, but again, there is this trade-off with cost.

The longest footbath the client has is 100 ft long, but he runs 2000 head of beef cattle through that every single day. So it's cost-beneficial for him. However, for a dairy herd of 100 cows, it's just not cost beneficial because the longer the footpath, the more solution you need.

So we actually aim for at least 3 dunks of each hind foot. So let's take that as our target. And now let's consider how long the footbath needs to be to make sure that we achieve those 3 dunks of each hind foot.

So if the foot bath is 2 metres long, are we gonna get 3 dunks, or do we need it to be 3 metres, 4 metres, or more than 4 metres? So how many, how long does the foot bath need to be to achieve at least 3 dunks of each hind foot? Just trying to do some maths myself then.

We all know that a cow is 2 metres long because of social distancing. So how long does it need the foot bath need to be to get those 3 dunks? OK, I think that's most of you haven't voted, so in the poll in there.

So, we've had 6% of people have said 2 metres, 21% of people have said 3 metres, 53% of people have said 4 metres, and 19% of people have said more than 4 metres. Brilliant. Well, I'll give it to both C and D, although you could say it depends on the size of the cow as well.

So, this is some research that was actually published, and this looks at how many dunks you get from each hind foot based on various, foot bath designs. So, the bars on the left-hand side, they're for 1.8 metre long foot bath, and then we go up to 2.4 metres for these central bars here, then 3 metres and then 3.7.

So, The blue bar is 2 immerssions, grey is 1, then we've got red for 3, green is 4, yellow is 5 immerssions, and, and purple is 6. And you can see that even at 3.7 metres, we're still getting some cows, so about 15% of cows or hind feet, that aren't actually getting 3 dunks.

So actually, to get 3 dunks of each hind foot, we need to be looking more towards 4 metres. And even at 4 metres, not every cow will get 3 dunks of each hind foot. So this is a 2 metre long footpath, and you can see here, counting the number of dunks, we tend to get 2 dunks of one hind foot and 1 dunk of the other.

This is the same farm, but with a new improved footpath. It's the first time these cows actually go through the footpath. And if you can see here, we're getting, on average, most cows are getting 3 dunks of one hind foot, but perhaps 2 of the other.

As the cows slow down, then all of them are getting 3 dunks of each hind foot. So we do need to be now looking at longer foot baths. Obviously, that creates more of a, a challenge in terms of, cost.

But one of the things that Wisconsin research showed when they were looking at design a foot bath is that cows, the foot bath doesn't actually need to be the full width of the cow. So you can see here, actually, the, the width of the foot bath itself is actually very narrow. This is 60 centimetres wide, because that's the width of the cows, where the cow's putting her feet.

So, if you've got a 4 metre long foot bath, which is 60 centimetres wide, the number of litres that you're putting in it is actually very similar to a 2 metre long foot bath, which is 1 metre wide. So this is where we can change the design of the footpath and basically get more dunks for your money. Other things that you can see, with this foot bath here are that, at the end, we've got a small pipe, which is like acts like an overflow pipe.

So the foot bath can never be overfilled. It's always filled to a depth of 10 centimetres, which you can see is creating a really nice good coverage of the foot. We've also installed a pipe and a bung at the end to make it really easy for the farmer to empty, When at the end of foot bathing, so you can see the bung, the bung here.

The only other thing I would change here in terms of design is, is having stock boarding along the gate here, but obviously, it would muck up the video. And also have sloping side panels to make sure that the feet always have to go in the foot bath. So if we actually look at what that might look like, this is the sort of design foot bath here.

Solid sides, sloping panels here, so the foot always has to go in the foot bath. And this would be the cross section here, so you can see only 60 centimetres wide. A big high instep as well.

The higher the instep, the, the shorter it is and the shorter the distance to that first step into the footpath. So, if you think about yourself, if you, if you're trying to get over a small wall, where you can take a good stride over it, whereas if it's a slightly higher wall, it just slows you down long enough, and your first foot placement is, is much, much closer to the front of that footpath. So, even where you can't fit in a 4 metre long footpath, say, for instance, you've got a 3 metre long footpath, if you just raise the height of the instep and the exit step, you actually increase the number of dunks that you get.

So that would be our, our preferred, Foot bath, that we would install now, and you can, you can either buy, fully automated foot baths for around 700 to 8000 pounds with this design. West Country Concrete do a prefab as well for about 1500 pounds as well. So there are different options.

All farmers can build their own like you saw in the video just now. So if we come back to our DD cycle, then if we think about what we're trying to do with foot bathing, well, it's a different side of the cycle to, treatment. So what we're actually trying to do is stop uninfected cows becoming active in the first place.

So dealing with any infection as soon as it starts to happen. And we're also crucially, trying to stop the recurrence of active lesions. So you can see if a farmer is just foot bathing, they're actually not doing anything about these active lesions that need treating.

Whereas if, we've got foot bathing in place and we've done the blitz treatment, then it's gonna have much, much more effect. So taking all of that into account, and I know I'm gonna be running over time, and I apologise, but, if we put all of this into practise, I just want to run through the case study that we did at Marcross Farm for, for AA. So I'm just gonna let Hopkin, introduce the project.

I'm Hopkin Evans with, farming here, Marcross Farm. Got a herd of 180, Holsteins, housed all year round. A digital dermatitis, it was a rumbling issue that it was something we'd see every time that we were in occasionally we'd be treating the father or treating the cows individually is one of our main issues here to deal with.

So that just gives you a little bit of indication about what the, the housing was like for the cows as well. So you heard Hopkin there say that, he's got around 180 cows housed all year round on mattresses and sawdust. He's right down on the South Wales coast.

Long standing digital dermatitis problem. He's had repeated flare-ups, and when I rang him saying, Can I come and do a case study on your farm, he was actually in the midst of an outbreak. He was already foot bathing 5 days a week, say, forming in at 5%.

And on a Friday, he was using parlour washings because he'd always done that. And then he was also already doing the individual spot treatment. So he was already doing everything that actually we needed him to be doing, but it just needed a bit of reconfiguration to get the maximum return on his time and investment.

So, In terms of identification, we found that 36% of the cows had a DD lesion, and when we broke this down, the vast majority of these were in that active, phase. So you could see we're in the midst of a real big outbreak. 54 cows, were infected in the herd.

So if you were looking at the cows at the feed barrier, 1 in 6 hind feet had an active lesion. So just think about the amount of infection that was, was in the herd. In terms of the treatment, we went through the 3 day plan, put all the cows with DD lesions through the crash for 3 days and treated them.

We used topical ox detach and cycling spray, just like I showed you in the video earlier, and we checked both feet when we had a DD lesion found on one. The feet weren't trimmed as part of the treatment because I didn't want to add in extra things for the farmers to do. Crucially, during the treatment phase, we didn't foot bath the cows either, because we didn't want to be treating them and then for the treatment to be washed off in the, the foot bath.

In terms of the outcome? Well, after 3 days, 8 of those initial 49 have not progressed fully to the healing stage, so they needed a little bit of extra treatment, just like this heifer 222 that you see in the, photograph there. I did a weekly follow-up of selected cases just to see how they progressed.

And again, I showed you the photographs earlier on. I did also request that all suspected DD cases were presented to me each week. Now, every time I turned up on the farm on a Monday morning, I had a whole yard of cows to, to put through the crush.

And, he said, all, all of these will BDD, but in fact, they weren't, they were other causes of lameness. And actually through the period of time, we had no more additional cows to treat. In terms of foot bathing, we carried on using formalin.

Hopkin was happy to use this. I provided some training in terms of PPE and health and safety to make sure this was all being done correctly, and I advised that he dropped from 5 to 2.5% formalin for the milkers, but he wanted to stick with 5%.

He wasn't foot bathing the dry cows, so I advised that he does this twice a week. In terms of other aspects, well, you saw hygiene on the farm, it could have been better, so we tried, to, to just change the timing of the scrapers and pay more attention to detail when scraping crossover passageways, collecting yard cow traffic areas, etc. Wanted more bedding to keep the cows cleaner, and, that's some of the things that he implemented.

Once we'd done our blitz treatment and changed the foot bathing, I went back at, to do a six week review. So again, I identified all of the cows that had DD lesions, and I also checked all of these that we put through the crush previously. Now, if our programme had worked, what we'd be expecting to see was a big shift.

In those bars over to the right hand side in the dormant stage. And this is what we found. So, we found that 8 lesions were still in the healing phase.

A few cows appeared to have gone back to uninfected, but the vast majority were dormant. And that was great news, because on top of this, we only had 3 new active DD lesions on previously uninfected cows. That was still within my 1 case per 100 cows per month.

So all looking really, really good. I went back again at the 5 month review, and you can see the situation was very, very similar. Those cows that we treated originally, we kept them in that dormant stage.

So we've been successful in treating them, and then we've been successful at, keeping them dormant. We had no new cases, and we only had that one recurring lesion. So that was our only lesion, throughout the entire herd.

If we break this down into some figures, you can see we started with 49 active or recurring lesions, so 17% or 1 in 6 hind feet with an active or recurring lesion. So by the 6 weeks, that was down to 3 and 1%. By 5 months, just one lesion in the entire herd, and 0.3%.

Absolutely fantastic to reduce it from that 17% down to just that, that one lesion, and all we did was follow that protocol and make a few management changes. In terms of lesion severity, well, these are the worst lesions at each of those, so that was our worst lesion at the very start. I said that, at our 5 or 6 week review that we had 3 new active lesions, but you can see from the middle photograph here, these weren't very severe at all.

And by day 142 at the 5 month review, that was the only lesion that we had. So all looking really promising. So I then left hopped in hopped into it for a little bit, and I went back 14 months later on.

I'd just say that at the end of the 5 months, he was really happy with how things were going. He was a bit annoyed that we had even just that one lesion, which just shows you that the tolerance of the farmer to the number of lesions they have really changes over time. And, the one thing he hadn't done was foot bath for dry cows.

So when I went back 14 months on, we had a drop from that 36% to 27% of the herd with DD. But we'd had a little bit of a flare up in terms of active lesions. So I wanted to really find out what was going on.

So you can see still the vast majority of cows are in that dormant stage, but we had 16 active and recurring lesions. So if you look at our percentages, well, we've gone up to 16 lesions or 3.8% of cows.

That's still well below the threshold that many would say, intervention is required. However, I wanted to see why we hadn't kept it where we, where we were. And the reason was the foot, foot bathing of the dry cows wasn't being followed out.

And these were some of the lesions that we were having in those, fresh cows. And so, had a word with his dad, and we worked out how we could implement foot bathing of the dry cows. And, that was then, implemented going forward with much, much better, results.

So, that was sort of a, a quick whip through, the study, because I know we're, we're pushing on for time. But just to show you sort of that protocol in action, and it, it, it is a protocol that still, I have farmers several years on coming up to me and saying, we implemented it and it worked, and now no DD is no longer, a problem. So if we just try to summarise all of that, bring it all together, we still have loads that we need to know about DD.

There are studies going across the world, being carried out across the world on DD to try and improve our knowledge on it. But I would say that we know enough to be able to control it at this stage, not to say that we might change some of the things that we do in the future based on new evidence, but currently we know enough. But the key thing for me is identification of all cases is key.

We need to identify as many cases as we can. Now, I, I know that when we go through and we wash the feet, that we're going to miss some cases. That's fine.

But we know that if we can get as many of them as possible, that we can still have a positive effect on the herd. If we blitz treat the cows, it's a much, much more effective way of bringing infection under control quickly, rather than just ad hoc treating cows as we see them. But we need, if we're doing blitzer treatment, we need to make sure that prevention is in place to stop it bouncing back.

The worst thing is you go through and do a blitz treatment, you don't put foot bathing in place and then it just bounces back and you're in the same position or worse several weeks later. And really, my target is less than 1 active or recurring case per 100 cows per month, and it really is achievable target. You can see at Hopkins, actually, we were, we were lower than that.

But I think as Hopkins's story, says, really, we, we, we shouldn't be getting complacent. So if things are working well, still make sure that you're keeping all of those prevention measures in place, because if one of them slips, then we can actually be back to, back to square one pretty quickly. And the key thing is to keep monitoring.

So once we've got everything in place, we monitor it by doing a DD score in the parlour every 4 to 6 weeks. If we start to see old recurring lesions, or old lesions coming back and recurring, that indicates that we need to just make sure that all the measures are still in place. So, Just wanna say a huge thank you for joining us for our first BCVA student clinical club.

We're hoping that the, these will be useful for you going forward and we, we're hoping that this is something we can maybe set up long term. We've obviously got our next clinical club on. Under the 18th of May, which will be on mastitis, the same time again, 7:30 till 9.

And there's just a little information there if you want to follow us on Twitter or Facebook, and also further information on becoming a steward at Congress this year. I know that we are up on time. I've gone over.

I'm really sorry. But I am happy to stay on and answer questions. I'm not going anywhere.

Where could we go? That's the question. Yeah, some questions have already come in, so, we'll get to them.

Also, would you mind me, Sarah, just mentioning about the World Veterinary Association congress because we've got a special ticket for students as well. So webinar vet is delighted, that we've been able to assist in the delivery of the World Veterinary Association Congress. It should have taken place in Auckland two weeks ago, but obviously due to the current COVID-19 situation, it got cancelled and so we've been able to take it online, so it's gonna be a mix of, We've got dairy, cattle, CPD, we've also got beef cattle CPD farm, we've got also got companion animal.

We've even got aquaculture. So there's over 100 hours of really varied high quality presentations by some leading experts. And for students, it's only 20 pounds plus VAT.

So I know being a student, having been there myself, you know, money's not always, easy to come by, but, you know, if you do have a spare 20 pounds and you're looking for some access to some really high level content that will really hopefully, give you some great insights going forward for your studies, then, I'm gonna pop the . The links in the chat boxer shortly while Sara is going through some of the questions and answers so you can have a check of that out as well. OK, so thank you very much for that little pitch.

So on to the questions. So the first question is from Eleanor, and she said, if the bacteria are unable to survive in the environment, how worried are we really about transmission between species, e.g.

Sheep to cow, which species have to literally share a space to be a risk. Yeah. So we still have a lot to know.

I mean, we know that, so I've been talking about slurry. One thing I didn't talk about was survival on rubber and latex gloves, things like that. So, we know that it can survive on rubber for several days, and latex gloves too.

So, there is the potential, there is definitely the potential for spread, and certainly, I see it, a lot in beef, beef and sheep units. Where we've, particularly where we've got, you know, sharing of handling space and yard space. That's a real concern.

Or you may have, you know, tools that you're using for, for both species. So it is, it is something that we definitely need to be aware of. I think that the proof is still to be, made exactly in how these These bugs are transmitted, but all we can say is there's an association.

So where we've got, sheep and cattle, together, we're more likely to see, see the disease in both. So it's just being conscious of, of biosecurity. I mean, they're seeing it now in elk, and deer as well, goats.

So it's becoming a, you know, it's evolving all the time. So we just, we just need to be careful and make farmers aware of the biosecurity risks between species. Brilliant, thank you very much.

. So the next question is regarding, obviously you said this is classed as an M1, this is classed as an M2. So they're just asking, what does the M stand for in the stages of DD? Yeah.

So the M stands for Mortilaro. So you may have heard DD, talk, discussed as Mortilaro. I think certainly in Ireland, they refer to it as Mortillaro.

And that is the name of the person that originally found it. A guy called Mortallaro in 1974 in Italy, it was discovered. So that's what the end stage stands for.

There we are. Thank you. I'm gonna apologise in advance for my pronunciation of this next one.

Spiro, spirocious, is it? Spikes, there we are. I do apologise.

The only, as you can tell, I never went to veterinary school, so apologies for all those listening in. I should have tried harder at school. The only cause of DD or if lesions are present, e.g., from corrosive foot baths, slurry, and other opportunistics like, fuzobbacterium can also cause DD.

So when we talk about digital dermatitis, we're specifically referring to . To the trepones. So, from all digital dermatitis lesions that have been studied, we found one or more of those three specific species.

So, certainly, without doubt, we'll find other opportunistic bacteria in there. So we think that the damage to the skin is done by these, repoines or spirokeets, and then optimistic bacteria are without doubt coming in, Coming in on top. The last year, I think it was either last year or possibly the year before.

Liverpool produced a really nice paper on all of the bugs that are found in DD lesions and complicated white line lesions and things. And there are a whole host of them in there. But, specifically for DD, the initial damage is done by the, by the spirokeets or the trepanema.

Brilliant. And I'll get you back one day for that, Tom. I know that you're the president of Liverpool and that's where we're based, so I'm sure our paths will cross.

Alice has asked if the cow is the main reservoir rather than the slurry exposure, how can the low prevalence in beef herds compared to dairy herds be explained? So, actually, it's an interesting one. There's actually more and more DD in beef herds.

So, I've worked with so many beef farms, so certainly it can be a problem in beef herds. And it comes down to more about the risk, the risk factors. So, like I said, you've got to have the bacteria.

On the farm, but you've also got to have the opportunity for the bacteria to get into the skin. So if you compare, like dairy housing compared to the beef housing, we tend to get much sloppier slurry, in dairy cows. So then it's more tends to be more corrosive on the skin, whereas beef units, You don't tend to get as much pooling of slurry, etc.

So you don't get that exposure and that damage to the skin. So we don't perhaps have, as much risk of exposure and transmission between the cows because they're not living in as much, as a, a moist environment. Plus, they tend to be outside a lot more.

Grass is fantastic for keeping the, their feet clean, which is why we see less STD out in grass. Brilliant, thank you very much. .

You show you obviously showed the video before about how to apply the spray and you know, clean the area. Once you've then revisited, do you keep repeating that treatment until you get the scabbing and healing stage? Yeah, so I just, I don't, ever actively, like, peel off the scab.

So, I would just, yeah, do, do exactly the same. So in this study, I mean, ideal gold standard is you keep putting them through the crush. In reality, that doesn't, that very rarely happens.

So, if I was doing gold standard, I'd put them through the crush for 3 days, and I would, again, wash off the foot with, with clean water. Dry the lesion. If a scab is forming there, I'm not gonna start pulling the scab off.

I'm just spraying, spraying the lesion. In the parlour, farmers will, I tend to get them as the cows come in to, to wash off the feet. Go down, clean the teats, put the units on, then, then go down and spray the lesions to try and give the, the lesion as much time to dry as possible.

So, it is going through and, and cleaning off because the feet get dirty, so we've got to clean it off to allow the spray to, to get there. Thank you very much. This one's regarding foot baths on parlour exit.

They've heard that it wasn't a good idea as the teat can still be open for some time, you know, potentially 20 minutes after milking and risk of causing problems, e.g., mastitis, if the pathogen entered the teat canal.

Is that something you've So this is this is always an interesting one, and I have 11 farm that has both a mastitis problem and a GD problem, and it's it was something that he flagged up as a concern and I think the thing that that. The concern is that the teat canal is still open, but it will still be open in the majority of cows 6 to 8 hours later. Because now cows, we, we've bred them for faster milking, so they have shorter, wider teat canals.

And some of the research has has just shown that they just don't, they simply don't close that quickly. So then, if we're, we're looking at making it easy for foot bathing, the other option is, as the cows come in, but then we don't want them, splashing stuff up onto their rudders before they're milked. So, for me, the parlour exit is, is the best place.

And, I've taken many chances with farmers that are worried about mastitis. And as, as long as the foot bath is designed correctly, and you don't get cows charging through, and you don't get cows, creating too much splash as they go through. Touch wood, I'm hugging the table.

I haven't had any comeback, from that, because it is something that I also have to be mindful of that I think if we can get the, the cow flow right, then that, that doesn't have to be an a big risk. Brilliant, thank you very much. Don't tell James Breen.

So Katrina's asked, in terms of robots, farms I've visited have lower milking visits recorded per cow on the days of footbath deposit robot exit. What have you seen used in robots and what success rates? Yeah, so, absolutely, we see less.

If, if you've got cows, going through a robot with DD lesions, and they're gonna be foot bathed afterwards, without doubt, that will affect robot attendance. So, with robot herds, it's really important to go through and do a blitz treatment. It is much, much more difficult.

It's part of the project I'm working on at the moment, with a farm near me to look at the cost benefit of doing it for robot farms. So, The options are that you go through, you treat everything so that when they're going through the foot bath, it's not hurting them. Because if a cow doesn't want to go through a foot bath, there's a reason why.

And it's usually they've got an open lesion. Or the other option is to, put a foot bath on the crossover passageway. And this is perhaps where I have most success with my robot farms, is where, the foot bath is on the crossover passageway.

The cows are pushed back prior to feeding. And then they're fed and the cows just walk through the footpath to go and feed, and that's a system that for me works really, really well. It obviously does increase the amount of work because it's not automatic for the it's not just completely automatic, the farmer.

Has to clean out the footpath, etc. Things like that. But I think it's, it's one way that can be really, really effective.

And it's certainly with the project, the robot farm project I'm doing with Farming Connect, here in Wales, we're, we're finding that it's working, working really well like that. Brilliant, thank you very much. So next question, obviously the video you showed, showed the cows walking through the bath at a you know a decent pace.

Is there any danger of too much time being spent in a foot bath? Well, it's really interesting. When you look at, some of the data sheets behind some of the chemicals we put in the foot bath, they say, we need around 15 seconds of contact time, which is quite a long time.

So I think that if we were to, I mean, I think, for me, would come from if we're using, say, something like formalin, and, they're literally stood in there. And that's, that's one concern with crossover foot baths, where they're, they're there constantly or where they're They're right by a water trough is that the animal can be standing there for quite some time and then you worry about burns, etc. Or you've got a very caustic product.

So I wouldn't be able to put a time limit on it. But I think, certainly, if you're, if they, if they're all going through normally, like on a parlour exit, I wouldn't be too, I wouldn't be too concerned. So I suppose I haven't really answered the question there.

I suppose, yes, the answer to the question would be yes, they probably could spend too long on it, but I couldn't stipulate how long. Yeah, as long as you don't stay in it, like you stay in a bath and just become a prune and you're fine. Yeah, yeah, don't, don't bath in it.

And then I suppose this question sort of, you just touched on formal limb, and this question look in terms of the health and safety concerns regarding that. Yes. So, I, I know I didn't have time to go into everything, tonight.

So I, I could literally spend 4 days on digital dermatitis. So, when it comes to formalin, there are significant concerns. It's a known, it's category 1B carcinogen.

So we know it causes cancer of the nose and of the throat. So, basically, if anybody's breathing it in, that puts them at risk. So in terms of the PPE that they should be wearing, it's a proper gas mask.

It's not just a dust mask, it's a proper gas mask with proper philtres. Goggles rather than just glasses. Should actually be wearing a chemical spill suit, and also gloves when they're handling it.

Now, this is only the handling of it in its neat form. So once it's diluted, they don't, you know, if they, if they say they're foot bathing on a Monday, it doesn't mean that all the milkers have to come out in this full sort of hazard, kit. But, certainly when they're handling, form and it's neat, they should be wearing all of that PPE.

So what I try to do on my farms where we're using formalin, I mean, if it can be handled safely, I'm happier than using it. It's, it's very, it's very effective at control of DD, but it has to be used safely. So you can set up either, you could either have an automatic system, in place, or automatic footpaths that deal with formalin.

Or you could use something like a Dositron. They're a couple of 100 pounds. Most farmers already have them installed in their parlour, etc.

And that will measure a known amount of falling down, out into the footpath. Or you can really easily set up just a double syphoning system, which is all closed. So where you have your IBC or you have your 25 litre drum, and that you have lots of tap systems basically, so you have a pipe going down into a vessel which is marked at the level of how much it needs to be filled to to get your concentration of formalin.

And, once that's full, you turn off your tap, the IBC, and then that, that vessel can just empty into the footpath. I hope I've described that, that well, so you can see what I mean. But there are options for its, it's safe handling.

But I think that we need to make sure that clients that are using it aren't just slapdash about it, because it can cause cancer. Fantastic. Thank you very much.

I always say there's no such thing as a stupid question. And that is very true. And also, if you're thinking of the question, I can guarantee that probably someone else is, and that's what's happened here.

Someone's support, sorry, this is a stupid question. But then someone has also asked a very similar question just below. So, as I say, no such thing as a stupid question.

Obviously, the, you know, examples you've been providing have been re relating to the hind feet. So do lesions only occur in the hind feet, or, you know, why are lesions more significant in hind feet compared to the 4 if that is the case? Yeah, that is not a stupid question because it's just something that I forgot to mention.

So thank you very much for raising that. So we do see DD in the front feet, . But by no means as much as we see in the hind feet.

So, mostly, I'd say 95% of DD that I see recorded is in the hind feet. So, the reason for that is basically that all the slurry comes out the back end of the cow. So all the muck, the, the splashing from the urine affects the back feet more than it does the front feet.

Now, the, the protocol is very focused on the back feet, because that's where we're gonna get our biggest win in terms of spotting lesions and treating them. If, I mean, the whole protocol was designed around trying to make this practical for the farmers, and if I said to them, you need to lift up all 4 ft of every cow, etc. Then they would, they would probably turn around and, and tell me where to go.

So focusing on the back feet. Easy to do in the parlour. We're probably going to miss a couple of front feet.

However, if we get the majority of lesions that need to be treated, then we're gonna get enough damping down that we can have, we can have that effect, and we can get control of the situation. Brilliant. Thank you very much.

Question here, Margo, is there any risk of foot bathing DD infected cows together with uninfected ones, or does the foot bath naturally kill off any infections, so it doesn't pass on the risk? They, the foot bath can definitely be overwhelmed. So this is what we tend to find when farmers are foot bathing and treating cows, but they've not treated all of them.

So for instance, if you take a herd that has 20% of cows with active DD. Now, if they haven't got a good foot bathing policy in place, or that foot bath is really contaminated and not doing its job, then definitely it can be, it can be overwhelmed. So, there is a risk, but it can be mitigated by making sure that, one, we're on top of treating infections, so we're reducing the number of active lesions that are going through.

And 2, that we're making sure that our foot bathing protocols are robust and are safe in terms of, effectiveness. So, I didn't, I didn't, I didn't mention this either, but say, for instance, you've got 240 litre foot bath, you put through 240 cows through that. A rough school of thumb is, rule of thumb is 1 litre per cow.

So, like I say, 240 litres, 240 cows. But if, say, for instance, you put through 500 cows and you had a high DD risk, you would be running the risk there. So, the most effective foot bath is the one that's just trying to prevent and not deal with infections too.

Brilliant, thank you very much. Someone's asked, with regards to caustic agents such as copper sulphate paste that can revert animals to M4.1 and cyst bursting, how does this relate to foot bath as frequently as possible, causing scabs to fall off?

So, with the, with the, the caustic paste, so the copper sulphate paste is a really, really concentrated paste. So, if we're mixing that up, what will happen there is, is that you, you almost, you're almost burning the lesion off, and as well as causing quite a bit of pain to the cow. And, and we think as well that it drives the DD deeper into the foot.

So creating more of a wet reservoir in that, in that dormant lesion. Now when it comes to foot bathing in copper sulphate, we're, we're dropping it down to around 5%. Sometimes if we acidify the foot bath, we can drop it down even lower.

So that's not as caustic as the caustic paste. But, what's the, so what the copper sulphates, say, for instance, you have an active lesion going through the foot bath and copper sulphate, you'll probably find that there's a, a little bit of a, a scab that's formed over the top. But when that comes off underneath, you've still got the active lesion because it's sort of healing from the outside in, or it's sort of, sort of almost, someone actually gave me a really good analogy here.

It's like barbecuing sausages. So if you want to barbecue a sausage properly, then you treat, you would treat it with the heat for over a longer period of time. So you're sort of cooking it from the inside out.

Whereas if you whack up the heat and you slap a sausage on the barbecue, you almost burn it on the outside, but it's still raw in the middle. And that's effectively what's happening, potentially with your copper sulphate and your formalin, is you're burning the outside, you get that scab over the top, but underneath, the lesion is still cooking away. What a great analogy.

Don't think I fancy a sausage and a barbecue for a while now, thanks for that though. If I haven't answered any of these questions thoroughly enough, then keep going. I'm happy to keep going until we've lost everybody.

We've got 2 more questions. We still have people with us as well, so it's all good. And actually I can answer one of the questions, so one more for you.

Pippa asked, are there any DD vaccine products in development for future use? And she said, thank you for such a great webinar. Thank you.

So, the, the main driver behind the vaccines was a guy called, Stuart Carter up at Liverpool, who unfortunately, has retired, although he does assure me that he is still working on vaccines. There have been vaccines, out there in the States, but they've tended to have to be really specific to the farm. And someone mentioned earlier about additional bacteria coming into the lesions.

And so they're trying to, they found that it has to be made up almost for that individual farm, rather than being a blanket vaccine that could be made, and, and rolled out across all of the herds. And some herds, I think it, it also made the GD worse. So there's a long way to go in terms of, the vaccine.

So, you know, we've been promised a vaccine for around 15 years now. One's not materialised, and it's gone very quiet on that front. So, I think for now we have to do what we can do to sort of firefight, with the hope that a vaccine might come out.

Later on, but I think certainly if we stop cows getting infected in the first place, that's, that's the key thing. It's the best vaccine. Brilliant, thank you very much.

And last question, will we be able to get a certificate of proof of attendance for this session? Yes, you will, I can answer that one. So yeah, so, all of you have attended this evening, when you, registered for this, you'll have either already have an account with Webinar vet or you created one.

So all you need to do, in the next 24, 48 hours is to log back in. On the right hand side, you'll be your profile. Go to CPD, record, and it'll be there and you just hit the green button saying download certificate, and it'll be personalised.

It'll have your name, date of the presentation, who it was presented by, etc. And so you've got that as evidence as well. So that is there ready for you to do, as the next 24 to 48 hours.

But also, this whole webinar will be also edited and made available on the website as well. So if there's anything you want to revisit, go back over, as I say, then you are more than welcome to watch this as many times as need be. And also also direct your fellow students.

To the recordings as well, if they haven't been able to, tune in today. Because I know some of you've had exams, I was saying, so if your brain was, their brains were a little bit fuzzled after the, exams, and they want a bit of a break, then obviously, they can go back and watch these recordings, in their own time, can't they? Yeah, definitely.

It's been a bit of an epic. It's been a bit epic. No worries.

Well, as I say, we had a good number of people stay with us through to the end, so, thank you very much for that. You know, nice some comments coming through saying that was really useful, Sara, thank you and thanks, thank you very much for your time. That was a great webinar, so I think it was really well received and really appreciated, .

As we were saying, sorry, at the beginning, there will be at the end a little survey pop up, really appreciate it if you could complete that and give us your feedback because that'll really help with the development of this series over the coming weeks. Obviously, please do tell your, friends, about these as well. You know, it'd be great to get as many people as we can on these, sessions for you, for the students to support you, during these, very strange times.

So yeah, please do spread the word on that as well. Does that sound OK? Is there anything else you want?

Yeah, no, brilliant, just as much feedback as you can give us as possible, because we want to know obviously whether we, we continue these long term for you and also different topics that you'd like, covered and, and just general feedback, about how BCVA can help students too would be, would be great. Brilliant. Well, thank you very much for that, Sara.

I learned a good few things today as well. So, next time I'm going past the dairy farm by our house, I'll, be able to say, oh, I wonder if we're doing that. But no, I really appreciate your time and I know a lot of the attendees today also appreciate that.

So thank you very much. And, when is the next one next week? So there's a normal webinar, BCVA webinar, a week tomorrow.

That's with Ian Richards on ecology, and he's touching on liver fluke as well. And then we've got a further webinar two weeks following that. I can't quite remember what that one's on, but we set, we've got webinars every, every fortnight.

And then, obviously, our clinical clubs are running every month as well, just for students. Brilliant. Well, there you are.

But I'd say if you go to the webinar vet website as well, you'll be able to see the schedule there and know that they're coming up as well. So thank you very much everyone for your time, and I wish you wish you an enjoyable rest of the evening. Thank you very much.

Good night. Good night.