Good evening everyone, and thank you for joining us for tonight's BCVA webinar. My name is Sarah Peterson from the BCPA board, and I'll be chairing tonight's webinar. Our speaker, Philip, is happy to remain online for questions, so please type any that you may have in the Q&A box during the webinar and I'll save your questions for the end of his presentation.

If you have any technical difficulties, then we've got Rob from Webinarett on hand, so please let us know what problems you may be having by using the Q&A box as well, and we'll do our best to assist you. If you can't see the Q&A box, then if you just wiggle your mouse, then the taskbar should become visible at the bottom of the screen. So it's my pleasure tonight to introduce Phillip Skuse as our speaker.

Philip is a principal scientist at the Morden Research Institute, where he's worked for almost 25 years to the day. In fact, Sunday will mark his 25th anniversary. So he's worked there on various aspects of sustainable control of worms and fluking livestock, and his research interests lie in parasitic diagnostics, detection in the environment, vaccination studies, and the detection and management of alkalinetic resistance.

He also has an interest in the impact of climate change on helminth parasite epidemiology, and the impact of endemic disease on the carbon footprint of livestock production. And if this doesn't keep him busy enough, then he's also knowledge exchange sector lead for livestock within Safari, which is Scottish Environment, Food and Agricultural Research Institutes. So Philip really is perfectly placed to talk to us tonight about, our topic, which is liver flute control in cattle and sheep.

So thank you very much for joining us. And now over to you, Philip. Thank you very much, Sarah.

Good evening, everybody. Firstly, I'd just like to thank the BCVA for the invitation to, to address you tonight. And to Sarah and Dawn who've been a big help in setting this up.

So I hope everything goes to plan, and you can hear me OK. Sarah said, yeah, Sunday was my 25th anniversary to the day of working at Morden, so. Nice to commemorate it with a little event like this.

As you said, I, I do work on aspects of sustainable control of parasites and livestock, increasingly, in fact, almost exclusively, fluke these days. And it's also interesting if, if you note from the, the title slide, there's a more than 100 logo at the bottom because But pure coincidence, this is also Morden's 100th anniversary, so I've worked there for a quarter of its existence. So it's nice to have a double, a double celebration.

So yes, we're going to talk a little bit about flu control and sheep and cattle. And I should maybe say a little bit about the institute in case I'm more them in general, in case you're not familiar with us. The foundation was established 100 years ago this year by, a group of concerned Scottish farmers and vets.

They used to travel around Highland shows and things and, and the, the, the bus that you can see there, which was a mobile laboratory. And as part of our 100th anniversary, we're going to try and recreate that bus. So we'll look out for that on the road.

We conduct commissioned research on animal health and welfare on behalf of the Scottish Government and other funding agencies, . We've got very nice laboratory facilities now, out in the Pentland Hills just outside Edinburgh. Our remit probably hasn't changed a lot in that 100 years.

We still work on, sustainable control of infectious disease and that includes viruses. Bacteria and parasites and involves the development of vaccines, diagnostic tests and improved treatment and control strategies. And I'm sure you probably use some, kits and reagents and vaccines and, and other preparations that have either been developed more than, or tested there, or some of your clients certainly, certainly will have.

So on, on the subject in hand, The loop, which I'm sure you're all quite familiar with. It's a highly pathogenic flat worm parasite. There's an image in the top right-hand corner which on my screen is not far off life size, about the size of, cornflakes when they're, they're adults.

The parasite has a complicated life cycle involving a tiny little mud snail, and you can see an image of one there just in, in the second panel. Unfortunately, they're not that big, and they don't come with yellow circles around them, so they, they are quite hard to find. But they're an integral part of the, the fluke's life cycle.

Fluke is a threat to sheep and cattle of all ages. There's no evidence of immunity or, or any sort of resistance or resilience to the infection. That's the same parasite in both, unlike.

GI nematodes and worms, which tend to be quite host specific. Fluke isn't that fussy. It'll also infect wildlife reservoir hosts, so deer and rabbits can keep the infection going.

And because it spends so much of its life history, out in the environment, in, on the ground, in the snails, it has a, a quite an environmental component to the disease risk. So climatic conditions are important and, and how and where, animals are grazed is also important and when, and, and we'll mention that as we, as we come to that. I've got a little video clip here which I hope you can see of some live wriggling fluke coming out of the, the bile ducts of a, a sheep's liver on one of our institute farms.

So they're quite big motile parasites. They're mostly filled with partially digested blood, that's the dark pigment, and they have a lovely habit of vomiting that up in in front of them as they go, but there's a secretion in there that we can use as a diagnostic indicator. I'll mention that when we get there.

So just remember that vomiting fluke in, in the video. I've been told at this point to try and pose a couple of, Of, of, of the easy questions just to, to judge the, the knowledge in the room and my knowledge as well. And I think this is the first of them.

So, the first question is quite simply, and I'm sure Sarah will pop in here with instructions as to how this will work and what the answers are, but when, when would you expect to see a buildup of fluke cysts on pasture in a normal flu season, and the, the options are a spring, the summer, the autumn, and the winter. I think like something that just popped up on my screen which I hope you can see and you've got time to answer. Yes, so everybody should now be able to see a little pop up box that's come up which has got those 44 options that Philip's just taken you through.

So this is completely anonymous, have a go if you're not sure. We've got over half of you that have voted so far. We'll just give you a couple more seconds just to decide before we close the voting.

OK, and we'll close it there. OK, so our clear winner with 53% of the vote is autumn. Then we had 30 30% saying summer, 14% saying spring, and 2% saying winter.

Well, well done, that, 53% because autumn would be my answer to that. You can never say never, and every year is different, but that would typically be when you'd see a buildup of fluke cysts in a typical fluke year, whatever that is. And you'll see, you'll see in, in context why we think that is.

I always like to show the fluke's life cycle because I'm partially because I'm fascinated by the fact that even works in nature, and I know I need to get out more. And I need to remember that this is the life cycle from the cows website because my sheep one that I use more often goes the other way around. We need to remember this one's going clockwise.

So you've got your fluke in the liver and bile duct systems of your animals that as adults, they'll shed eggs and shed lots of eggs, upwards of 50,000 each a day, and those eggs pass out in the faeces. . A little larval stage will develop inside the eggs once they're released from the faecal pats, and the speed at which that happens is dictated very much by weather conditions, how wet it's been, how warm it's been, and they'll go off in search of those little mud snails.

And much as we struggle to find them, the myosidia hatching out of the eggs don't have any trouble finding mud snails. So they'll, they'll they'll find the snails and penetrate them and develop inside the snail's tissues and also come amplified there, so. You can have a, a big amplification in the life cycle, and the next stage is shared several weeks later, again, very much depending on the weather.

And patterns in, in the meantime, those little circa or like little tadpoles that come out onto the surface of blades the grass, and they'll ultimately form a cyst, and it's those cysts that animals eat when they're grazing. The infectious stage is really the system on on pasture, and, and we know now that they can last a bit longer than we thought they could, and, so the weather patterns and, and what sort of weather you have is important as to how long that part of the life cycle can pers persist on, on pasture. And before we move on, we shouldn't forget that wildlife are important.

I mentioned them earlier. You've got deer and, and, and rabbits and hares can, can just keep the life cycle ticking over even when livestock aren't present. So we move on, there is a basic seasonality to the fluke cycle, and that's kind of what I was getting at with that first question.

The normal buildup of, of metasircari insists on pasture would be in the autumn. Usually, it's worst after a wet, warm summer. And there, but there is a bit of overwintering, very much depends on what sort of winter you have, whether it's a nice mild winter, which will allow some of the snails and some of the fish to survive, then you start to see disease out of season.

You can get animals picking up infection of pasture in the spring, and that can quite often be a surprise to the farmers and even to some of the vets. Normally you have animals shedding, eggs and carrying them over into the winter and you can see, infection of, of snails at odd times, but the normal pattern would be most of the nail action was in the summertime, the systems in the, in the autumn disease in the, in the winter. So But it is all about the snails.

And I mean, much as we struggle to find them, they are everywhere pretty much sort of. Snail surveys of, of the UK and Ireland. They're pretty much everywhere you look for them, certainly on farmland.

Well there's a lot we We need to know about them. We, we don't know as much as we, maybe we should know about them. We know that birds are can eat some of them.

Some people think that's a good way to get rid of them, but there's good evidence that they also transmit them, on their, on their feet. So it's a really difficult thing to get to, to control, and it's an added layer of complication that sort of nematodes don't have. And I mean, nowadays we don't have a lot of options around snail control, but back in the day, and this is a very famous gentleman in fluke research.

This is the, the legendary CD Oeran show from the Central Veterinary Laboratory. In Weybridge, this is how you would have controlled flute back in the day, the poisoning the snails on the ground with copper sulphate and other nasty chemicals. Unfortunately, we're not allowed to do that anymore, but we'll come back to that in context.

Just to show you what I'm sure you've seen many more cases than, than I have of this sort of thing, but this is what a large, infestation of, of flu coming through the liver of a sheep can do, rather gory image from APHA, so the liver is very badly damaged and, and. The young fluke have encountered a blood vessel or vessels on the way through and the animals basically bled out. You'd more typically see chronic fluke, which is a buildup of the adults.

But you can see that if you've got lots of adults there, you've obviously had lots of immatures as well. So the liver tissue is very, very fibrose and, and very friable. But also you'll see the bile duct and the gallbladder are very distended and kind of leathery, which you wouldn't normally see.

And, and it's, it's quite, sobering to think that that gallbladder bulging at the bottom there is full of millions of fluke eggs, just ready to go out and hatch and look out for the next lot of snails. So you can see the potential for infection there. It looked very damaging in shape, but it may be less clinically, obvious in cattle, but it will cause cattle problems, and this is a nice image that Neil Sargeson kindly lent me from the vet school in Edinburgh of the liver of a, of a, of a, a bovine, and you can see how dramatically it's reacted to the fluke infection that the bile ducts have kind of turned to chalk.

The condition known I'm sure all the clinicians will know pipe stem fibrosis, but that would lead to the liver or big chunks of it being thrown skip at the abattoir. You can see odd flukes lying about there, but it's the, the bovine's attempt to encapsulate the parasite and prevent it feeding and laying eggs, but it can lead to a right mess of the liver. We're quite often asked what by producers what, what is actually, what is the cost to the farmer.

Surprisingly, there isn't a huge amount of data out there and some of it's conflicting, some of it's quite old, but some of the figures that are quoted would be a, a 10% reduction in live weight gain in adult sheep and cattle. . Larger reductions in, in younger animals, but also things like poor scanning rates and reduced feed conversion ratios, things that maybe the farmer wouldn't necessarily see.

But they all add up and, and add, add to the cost. Elex the levee board, put some figures on this several years ago, 25 to 30 pounds per head for sheep. A more academic Swiss study looked at cattle, beef and dairy, and had figures of around €300 per head in a given year.

We've done some work with Harborough Limited. I'm sure many of you will know feed manufacturers. They also have access to some of the abattoir, data of animals, healthy animals coming down the line in the northeast of Scotland.

And it's, it's quite interesting that, you know, they have access to large numbers of animals, which means we can say slightly more, statistically robust things about that, but you, you have animals that are flaky. Tend to be lighter, and when they get to the abattoir line, they tend to be older and it can be as much as 27 days. It depends on the breed and it's a wee bit more complicated than that or where the producers from, but, basic take home messages that flip the animals tend to be.

Older, . And haven't put on weight so well. And then another study, just a sort of a different take on this was the inability to control fluke on a sheep farm quite near our institute cost the farmer 20,000 pounds to, to, to sort out the problem and it turned out to be a drug resistance issue, which we'll also mention in passing.

And then when the animals do get to slaughter, to slaughter, quite often, their livers are so badly damaged, they have to be condemned, and that's an indicator of, of burden in a given year, with all the caveats we mentioned. And the, the typical running rates would be about 10% for sheep and about 25% for cattle. So having said that, maybe fluke isn't as clinically obvious in cattle, you can see that it does, it is a big hit.

And the condemnation rates because of how the liver responds to infection. And just to give you an idea of how fluke bounces around, incidents over time, I'm very grateful to Shanon Mitchell and colleagues at APHA who keep me up to date with these nice timelines. So this is a fluke incidences, so acute and chronic in sheep and the chronic fluke in cattle.

So these will be diagnosed at the, the VI centres across the country. So the brown bars would typically be the, the numbers of, of submissions tested on the blue line is the numbers diagnosed as having fluke. I think this is more than just PMs.

I think this also includes, diagnostic samples coming in, faecal samples and, and various other things, but you can see the way the incident bounces around and it really spiked around 2012 and 2013 and we had a very wet summer followed by a very mild winter, and it showed up first in a cute fluke and sheep and shortly afterwards, a big spike in chronic flu and sheep, so the mackerman was. Starting to see lots of dead animals around the country, sadly. And also you can see there's even a bump in the, the chronic flicking cattle.

It's been on a bit of a downward trend since then, apart from a bit of a bump around 2017. I'm not quite sure what happened there. I need to go back and look at the, the weather patterns.

And it's interesting we've got data right up to the second quarter of this year. You know the submissions are quite down across the country, but I guess COVID maybe has something to do with that, but. But also the incidence is, is done, and we think the reason for that is.

A very hot, dry summer in 2018 and, and pretty dry conditions since then, especially around springtime, the years since, we'll come on to that because, weather is important, it's not the only thing and I mean fluke has always been a condition, a disease of the West. I apologise, these are, these maps are a little bit out of date, but they show again from what was the VLA at the time. Was a, a variety of different host species.

There will be alpacas and cattle and sheep and goats in here, but always been a condition in the west. It's increased in the west, and it'll be more than that now, I would imagine, but also it's moving east and, and also north. At this stage, I sort of try to joke that Scotland's remains fluke free throughout, but sadly that isn't the case.

We have exactly the same situation. West of Scotland is, is very much fluke central even though it's quite far north. So what's changed, certainly there's an element of climate around this and weather patterns, public climate change, if you will, warmer, wetter summers, milder winters, longer grazing seasons, so more chance to pick up an infection.

For more extreme events of flooding, for example, can disseminate those little snails. They're very easily washed around on the margins of flooding events and can end up in, in, in, and see new infections. We have a bit of an issue with drug resistance, specifically to one product, and I'll mention that later.

So you're all familiar with the lobendazo story. The things that farmers sometimes forget animal movement is a big contributor here because the animals going to and from farms and on and off markets, they're out wintering being brought back in, onto a farm, and if, if they're not receiving an effective quarantine treatment on arrival, then that can be very challenging. Because there's not many farms in the UK that wouldn't have the potential to set up a snail infection, and, and have the habitat there.

And a slightly more contentious area more recently would be around agri-environment schemes. Where farmers are incentivized to either restore or introduce wetland. Onto their farms, or retain wet areas, so that can be waders grapes, for example, for to encourage wetland birds or protected habitats for things like majack toads that are protected species, but there's a requirement to graze those areas and A few farmers are a bit reluctant to, to do that, perceive there's a fluke risk there and there's a fair bit of interest in, in examining it what it actually is there, what, what's the evidence around that.

So it's something we're, we're involved in peripherally. So, on to sort of the disease itself really and clinical signs, what to look for, and you'll be much more familiar with this in the field than me, but sadly 2012 and 2013, sudden death was one of the clinical signs. This image was actually taken in 2013, spring.

So severe abdominal pain, liver liable to rupture, very badly damaged animals recumbent and unwilling or unable to move. Also with the With the chronic infection, you get this very obvious anaemia and, and bottle jaw in sheep and, and you can even see it in cattle, but the sheep in that little insect is his face is very swollen. I've never seen it other than textbooks, but you could see that from 100 yards away.

So the animal's very anaemic at that stage, so the membranes around the eyes and the gums are very, very white when they should be nice and pink. And, and just general little thrift and it can show up in, in cattle. This is a fairly emaciated dairy, dairy cow, so poor performance, weight loss, poor body condition, things that merit further investigation.

Could be other things, could be worms, could be various other things. You need springs to mind, but it does certainly merit, yeah, the suspicion of flu in that situation. So I've got another question for you, and this will test whether there is falling asleep or not.

Got a series of diagnostic options here and I just wanted to know which of these diagnostic tests would give the earliest indication of a liver fluid infection. Was it A, copper antigen eliza, B faecal leg count, C antibody eliza, blood test, or D, liver and bile duct enzymes. So that's your GLDH and GGT that you'd be familiar with.

So let's give you a few moments to think about that. So A was copper Anderson, the speaker the account. C is antibody Eliza.

The is liver bile duct enzymes. So we've got a few just thinking about the answer to this one, I think a little slower, slower off the mark. Nearly 2/3 of you have voted, so we'll just give you a couple of seconds for the remainder to, to make up their mind.

OK, we're closing it now. Brilliant. So, we had, nearly 80% of, of, watchers voting, which is great.

And in the lead was A 44%. Then we had D with 30%, C with 17%, and B with 10%. So A was our, our, most popular answer there.

OK, that's, that's interesting. I, I would maybe disagree with, with the majority there. I would always say the antibody goes positive first.

That can go. Positive in a blood test within 2 weeks of infection in sheep and cattle. So that would be my early indicator.

We'll talk about coupang in a minute, in context because it's my next slide, I hope. Yeah, just to run very quickly through the flu diagnostic options, they fall conveniently between invasive and non-invasive tests and certainly postmortem and meat inspection are invasive, but they're pretty unequivocal. The fluke is a problem and also if you have the time to look, you can see whether it's a cute fluke because that's something we struggle to diagnose.

You can blood sample animals for, for liver enzymes, and I hope the question wasn't confusing, but I would say this is an indicator of infection, but it's not the earliest, and, and it's a bit non-specific. So, blood sampling for liver enzymes and bile duct enzymes is useful but not on its own. The blood sampling certainly for anti-fluke antibodies, which is what I meant by the question.

Would be a pretty good indicator, especially in, in early, in, in young animals, especially, yeah, young lambs and calves, because the only flu infection they're likely to have seen is in that given season. So blood sampling would be a very good early indicator and, and people do use groups of certainly sentinel. Sheep can be very useful to, to get a feel for what's actually happening, when's fluke actually starting to come.

A little bit expensive, and it does require you guys to go out into the field and take the samples for the farmer, so it's maybe, maybe the expense on the logistics maybe make it less used than it could or should be, but it, it would be my preferred test certainly for, for monitoring. But in terms of the non-invasive tests, I mean, the clinical signs, so hopefully the farmer knows what to look for and can be suspicious, see anaemia and, and things like that. Dairy farmers have the option of the bulk tank milk, Eliza, so looking for antibodies again this time in milk.

So it's a convenient sample. It's already been taken for other purposes, so chance to do a bulk tank milk, Eliza is useful. But by far and away the tests that most people use, I'm sure some of your practises offer this would be a faecal eggplant.

It's quite a simple sedimentation of fluke eggs and, and, and water is what we would typically use, but, it works pretty well, yeah, 3 gramme sample, yeah, and it, it, it takes a little bit of time and you can't produce or process too many in a day, but it's a pretty useful indicator. The the only sort of drawback is that it only adults look to lay eggs. You have to bear in mind that the infection's been going on for 10 to 12 weeks before you see any eggs and.

Then the copper antigen Eliza, which is, it's a more, modern test, I guess it's appeared in the last few years, . And initially a kit came out maybe 55 years ago, maybe slightly longer, and we did some work with that testing in the field and it really had promised to work really well in experimental challenge infections where you're in control of everybody getting infected at the same time. The, the dynamics of, of, of testing were, were very, very, encouraging.

Maybe it wasn't as sensitive in the field as we'd have liked, but the company, to be fair, that produced it, BOX in Belgium. Went away and made the test more sensitive, and now it's a routinely used, test. It's a little bit expensive.

It only works with individuals. You can't sort of make pools like you, you would with faecal samples, but, for the same reasons that you don't pull the blood samples. But you're looking, you're looking for an antigen this time, not, not an antibody.

And it's very sensitive, very good indicator of treatment outcome. So it's really starting to find its feet now and, and become much more used. So that becomes positive typically maybe 6 to 8 weeks into an infection where egg count comes about maybe 8 to 10 weeks in.

There's a little bit of an advantage. It's a very convenient test for us in the lab because we can store samples, free samples, process them all at once, and that, that, that really helps us because the egg counts are a bit more difficult. We'll, we'll move on from that, but Sort of sad state of affairs.

I know this is really cheap, but many farmers, and most farmers don't do any testing at all, so they're, they're trying to base their control really on, on very limited information and maybe doing what they've always done or doing seasonal treatments. So it's a bit of a challenge to, to maybe change that mindset. Just a little bit, I'm conscious of the time moving on, a little bit about fluke risk and forecasting and it does come down to What's the weather doing to the snails, and it was encapsulated in a formula way back in the 1950s by himself, Olenshaw, so it's still called the Oorinshaw index.

And it's, it's a, it's a measure of evapotranspiration, how dry the weather's been at certain months of the year, and this is still used as the backdrop to the, the mainland UK nati parasite forecast, which has a flute component. It's always worth having a look at the anomaly maps on the Met Office website. It shows you how dry various seasons, months have been compared to normal years, and it's, it makes for a very interesting reading.

And in April this year was, was incredibly dry, and I think May was as well. So, currently fluke risk we're considering to be low and late, . And that's the legacy of the hot, dry summer I mentioned in 2018 and the spring of 2020 it's been exceptionally dry.

I mean it has been wet since then, it's kind of got a bit dull, dull wet weather since, but I think it fluke's taken a bit of the hammering over the last few years and it's a bit lower than it normally would be, but always something to watch. You can never say never with fluke. And I've got a, I think this is the final question, maybe not.

We're gonna move on to think about treatments. Third question of the, the multiple choice was which leucoide has activity against rumen fluke, albeit without a label claim, and I'll mention rumen fluke in a minute. So the options are A, closantil, B, nitroxenol, C, oxyclocinide, and D trilobendazole.

He's on the case, at least she's awake. Most definitely. OK, so we've already got more than half of voted, so I'll just give you.

Few more seconds just to just to decide. Again, it's all just for fun, we don't know how you're voting. OK, so we're nearly 80%, so we'll wrap it up now.

Brilliant. Again, we've got a winner here with answer to C, which is 53%, 23% going for D, 15% for A, and 9% for B. So the winner was C with 53%.

Well done to those who've gone for C, because that's the right answer to me anyway, oxyclozide would be a. And acknowledge women fluke treatment, albeit without a label claim in the UK. We will come on to that.

In terms of what options farmers have for controlling fluke in, in normal sort of flaky seasons, there are kind of four things I would typically think of as practical options. Fencing might be one, and it doesn't have to be permanent, but just to keep Animals out of flicky areas at fliky times, but the challenge is then knowing what a flicky area looks like. Drainage would be an option, but again, we mentioned that agri-environment schemes might go the other way around.

Housing is becoming increasingly an option, certainly for cattle farmers, as you well know, but increasingly for sheep as well, especially in really bad fluky areas, bringing animals in over the winter on slats seems to be quite a popular thing. And then ultimately what most farmers do was, will, will be to treat, and as we said, it's usually without any diagnostic. Indicator that they should and, or without any indication of whether the treatment that they gave worked or not.

So that's something that we're always keen to try and improve on. I'm now gonna parasitize a good friend and a well-known BCVA man, Andy Forbes, Professor Andy Forbes, Glasgow University, ex-M Mariel, ex cows, ex Animal Health Ireland, very authoritative on everything to do with. Well, all livestock really, but he, he would view winter housing of cattle as, as an option of a cornerstone of flu control because they're, they're indoors now you're in control.

You shouldn't be picking up infection. Now you've got to, you can exert a bit of control over this. And think some work that that Andy himself did with Fiona McGilberry.

Many of you will know also Ex Mariel, and, and Johannes Charlie, some of you might know a bit in Ghent in Belgium. They were looking at the stages, I mean, it's a, it's a lot of work, to actually go through the livers of cattle, at certain times of the year. But the surprise was that most of the, larger portion of the fluke and the livers of the animals of typical housing time were adult.

I might have assumed you'd have a good proportion of immatures there. I mean, obviously it depends on the year, and immatures are really hard to find because they look just like mashed up liver tissue. But I'll take their word for it that there seem to be a lot of adults there and that.

Yeah, improves your chances, I guess, of killing them because we have, we have products there that we know will kill adults at certain times of the year. So just to look across the board at the flu aides, very much frontline fluke control, lots of people do this routinely. Again, a picture of that from Andy, the top right hand corner is all the nice boxes you see in the markets and the new vet's practises, quite often the products end up in the back of the shed with their labels missing, and that's again something that we're, we would be a bit concerned about.

Although there might be lots of products on the shelves, there aren't that many actual products to choose from in terms of actual active ingredients. And as far as I know, you folks might know better, no new products in the pipeline. As far as I know, the drug of choice, certainly in sheep has been trilobendazole because it can kill right across from two days of age right through to adult.

You can see that it's from about 2 weeks of age. And cattle, it's a slightly different scenario. This is a scoops, or sorry, a carrier's image, so it's, it's more cattle products.

But then your products like nitroxen and closanty that come in at about 7 or 8 weeks, and then you get into products that really only kill adults, of course not to closing night. Allbendazole. Obviously, we're talking about susceptible populations here, and you notice that the triple asterisk get oxyclozinide because it can kill the flu also.

The thinking around around treatment in the winter time, I mean there are two schools of thought. One is therapeutic, where you're really treating for the individual animals benefit with cattle presumed not to be grazed again. So any effect of leucoide at housing would be a reasonable choice.

You may need to retreat again, if there's a high percentage of juvenile fluke. I mean the issue would be in a bad year, how would you know? And, you know, one way to do that would be to monitor the animals while they're housed, so look at their daily live weight gain, bearing in mind there might be other things eating up as well.

But you could use, faecal egg counting to give you an indication of when have you got adults in those animals and when might you consider treating them. And and then maybe a more strategic long-term approach is really around. Trying to prevent contamination of the farm, and infection of the snails, the cattle that will be going out to graze the following season.

So as I said, the drug of choice has been trilobendazole. Although there is a school of thought that things shouldn't use trilobendazole at all in cattle because they don't really need it. They don't suffer from acute fluke that much.

So that, you know, in an ideal world that would be you treat two weeks after housing when all the immatures are now in the liver and you can kill them. But if you move away from that, your options become things like losanty, nittroxenol, or the poon version of trilobendazole, which has a, which comes in slightly later. Again, you were treated housing, and the advice would be to retreat again 8 weeks later, .

And then, then you get into the real adult aides, so again, treated housing, but the intervals longer, so you're waiting for any immatures that have haven't been treated that first time to become an adult and you get them the second time. And you can use things like the egg count to determine the efficacy and or the need to treatment, . The issue on the, on the right-hand side in terms of option two is don't put that early treatment in, just delay the treatment for 8 weeks and into housing, but you can see the double asterisk there leading us to be wary of risk of losses if animals are heavily infected, the housing, and again, it's, it's kind of knowing or having evidence that they are or aren't, heavily infected with housing.

And then when you think about, maybe, we think about grazing animals that have been out over the winter, I mean some will be housed and then it'll be turned out. So ideally should be free of a patent infection. They shouldn't be shedding eggs and a leucoide treatment 8 weeks after turnout, it'll kill adults would be a good option there.

And for out wintered animals, depends when they were treated last and what with, but a lekide treatment 8 weeks after the previous treatment would be the option. Again, we're trying to limit. This sort of extended fluke egg output and grazing stock in the spring and summer.

So, so you're getting egg laying, removing egg laying adult fluke and trying to prevent infection of the snails. So that's maybe more of a farm protection idea. So, and here are some of the listed cattle leucoides off the sort of a screenshot of the cow's website, which is always well worth a look, and some of the products that you'll be very familiar with, the trade names, and, and the active ingredients.

Some are drenches, some are injections, some are coons. The thing to bear in mind very much is trying to operate around the meat with whole period, but increasingly for the dairy guys. The milk withhold, and that's under constant review.

So it is quite complicated for farmers to get their heads around that and they do need good advice. You can see some of the products come as combinations before you've got a warmer there as well, . Again, I mean, there's some discussion about, well, would you be treating for worms at a certain time of year?

Would you be treating for fluke? So it does bear some, it's worth investigating whether you actually have fluke and worms going in the same time, use a fluke drug if you can for fluke. So, but it is, it is.

Complicated. I, I will struggle to, to keep up and what's driving it really is the direction from, from, well, from Europe initially, but it's the zero tolerance around residues in, in certain, in meat, but certainly in milk, it causes problems for dairy farmers, . And there have been various, high-level discussions around what is and isn't permissible and, and drug companies scrabbling to try and get, claims for, for certain products and certain withdrawal periods.

So I'd always refer people and it's passing the buck, I know, to, to look at the NOAA or VND website around flucosides and dairy cattle because it's constantly under review, constantly changing around this traffic light system of what you can and can't use and when. And he's very kindly sort of summarise the, the sort of real take home messages from that as to which products you really can't use. So the red ones you really can't use at all.

And the, the green ones you can, but under very precise conditions. I not oxyclozamide withdrawal claim has gone out from 72 days to 108 sorry, hours of milk withhold. So it's constantly changing as, as companies, re-register products, but it's well worth keeping up to speed with what you can and can't do.

We're just moving on to a little bit more, maybe more research, but I, I hope that it's of interest and practically relevant for you. It's a project that we were involved in, quite recently, under the leadership of Professor Diana Williams, University of Liverpool, and I'm very grateful to Diana for giving me some slides to cover it. It was a joint project with I say with Liverpool and ourselves, but also the centre for Ecology and Hydrology, who are real kind of ecology snail experts and SRUC who have real expertise in, in farm economics.

But the unique thing was that we were funded through an industrial partnership award with the contributions from all of the levee boards and Dairy Co. So we had QMS, we had HCC in Wales, AHDB and Agrisearch in Northern Ireland. So you could see how important Fluke was at the time.

I guess the fact that this was, would have been granted in 2013 was, was no surprise. And typical of what happens then, you get a flute project and the weather improves. So, yeah, so our, our flu field work was more challenging after that, but it's been a very interesting project.

And kind of what, what drove it, I guess, was that we knew from previous work that Dina's group had done, Catherine can very nice paper on the vet record. Looking at the climate really drives the spatial distribution of look at a regional level. It's not just the weather, but there are differences between farms and even neighbouring farms.

The, the little graphic on the right, I'm sure some of you have seen it, but it's a traffic light system of scoring on the boat tank Eliza, with various dairy farms across England and Wales. The red ones had had quite a high positive flute count. And if the weather was the sole driver, you'd have clusters of colour of all the same.

But if you look at, for example, Southwest Wales there in the northwest of England, you'll see that you have all the different colours close together. So you've got farms with very different risk, fluke risk around that that are very close geographically. And the idea was, could we use this project to really sort of explore and capture some of the reasons for those differences.

Apologies, this is not the easiest slide to see, but just to give you an idea of the structure of what we tried to do, the sort of first work package was around developing herd level diagnostics, and we already had a prototype bulk tank milk Eliza for dairy, but we didn't really have much for beef, so we set about trying to improve that situation. The second work package was all around the snails really understanding snail habitat and can we, how do we measure that, monitor that, recognise that. Yes, the core of the project was really around the risk factor analysis.

Work package 4 was more around the economics at a sort of herd level and the national level, and Work Package 5 was an attempt to pull that all together in a, a pilot intervention study to see if we actually change some of these risk factors. Can we, can we do something to improve the fluke situation? As I said, as is typical, the weather improved dramatically in 2014, so it compromised some of our attempts to do some of this work, but it was quite an interesting, output and we package one.

Which I had some responsibility for was was to develop herd level diagnostic test. I say we had the bulk tank, milk for dairy, but we didn't have much for, for beef. We did look at the composite, we did look at the copper antigen in this regard, and it was very good at the individual level, but it doesn't work well as a composite because once you get one positive in amongst the number of negatives, the whole test tests negative.

So you have potential for lots of false negatives, which you don't get with an egg count if you're prepared to count all the eggs. So we came up with a, a composite faecal egg count, very similar to the one that, Liverpool published for trilobendazole resistance, sheep, but it was much quicker than testing individual dung samples, and, and it does give a good indication, and we published that. I'm trying to remember where it might have been the vet record.

So it's there if people want to have a look at that. And as a little sideline as well, Liverpool, we're able to develop a penzide, penide version of the blood test. So again, that's a step, a big step in the right direction to make testing much, much quicker, much more penide and the animal side, so farmers and vets can make much more rapid decisions.

I mentioned a little bit about the snail work. This is, very much led by the CEH guys, the snail experts, . They coined a very nice term to describe what sort of habitat snails like the Goldilocks effect, so not too acid, not too alkali, not too much traffic, so.

Snails just like it just right. So it tends to be wet habitat but not underwater, bare mud. Which usually has the snails feeding algae on it that they feed on, but not recently disturbed.

They don't like too much traffic. Usually open, not shaded by hedges and trees or long vegetation because that tends to be too dry. So areas would typically be depressions around tractor tyre ruts and poached areas and natural sort of water features.

It could be also cleared drainage ditches on the banks of ponds and streams or leaky water taps and pipes. So it's worth having a sort of a real objective feel for what a snail habitat looks like, and we're learning all the time. And we're even in contact with old Orangeshaw, who has probably forgotten more about what you know, habitat looks like than any of us will ever know.

But to add some some more science to, to this, Liverpool group did a very intense study on, I think it was about 40 dairy farms in, in Shropshire, so very intense snail hunting. Speciating the snails as to what species are we dealing with here. And also, are they infected with fluke or not?

And you'll see the infection level isn't that high, it's it's sort of single figure percentage and that, that's pretty typical. You don't need all the snails to be infected to have a fluke problem. But I guess the kind of real core of the of the project was around farm level risk factors and that's where most of the work focused on that.

Sort of 3 work package, so 195 farms were, were included in this study, involved very detailed questionnaires with data collected on all sorts of demographics and herd health, pasture, what the pastures used for land use, all those sorts of things and around, cattle production, fertility, and, and treatments and all the rest of it. And this is where the sort of clever guys get involved and this is the typical sort of data that they'll start to collect is all the different risk factors and then Subject that to a very detailed statistical analysis, and the three biggest risk factors that came out of that were buying in stock, typically cattle, with a reluctance to quarantine, treat them or even keep them away from the rest of the herd. Presence of sheep already on the farm because as you remember, they're the same parasite on both on the length of the grazing season, they were the main, drivers of fluke risk, certainly in the UK.

And if, if anybody's particularly interested, there's a, a synopsis or a prey of of of a final report and various other bits and publications linked to that, that's easily, easily found online, at PBSRC, so if anybody's interested, you can have a look at that. Just want very briefly to move on quickly because I mentioned rumen fluke and, I always like to show this little video and I'm glad the sound's turned off because the abattoir guys were swearing, but it's adult ruin fluke on the stomach of an Irish cow. It's quite a recent thing we've, we've been finding.

I'm sure you've seen them too. It's a two-ho flat worm parasite, like liver fluke, very common in the tropics. Maybe they have been around longer than some people think they were described in Glasgow back in the 50s.

We thought we knew what species they were at that time. Thought to have a similar life cycle to liver fluke, and they're often found as co-infections, but were thought to be fairly innocuous, things I always like to show this as well, and this is, this is the tropics, so you can collect the rumen at the abattoir and wash out the, the rumen fluke, a big handful of them, and stir-fry them so they're, they're seen as an alternative protein source in parts of Southeast Asia. It usually puts people off their tea, .

Yeah, they're technically perti stones. Their eggs started to appear in the last 10 years or so in faecal samples. Initially, I think they just thought they were kind of clear looking fluke eggs, liver fluke eggs, but they, they are a different species.

We have had some clinical cases and some deaths, and notably in 2012 when everything was going a bit pear shaped. Thankfully, clinical cases are still rare. But the parasite itself is becoming increasingly common.

60% cattle, 40% of sheep in Northern Ireland. Big numbers in, in, in the, on the mainland in Wales, Welsh cattle. The big question has always been how important are they, and that really depends who you ask.

The farmers think they're very important on the next big thing, and they, they may be right. We maybe need to find out a bit more about them. But I know some vets are quite dismissive, but I think we maybe need to, to find out a wee bit more about them because they can cause problems.

This is a, an outbreak on, the UCD farm in Dublin, . Where they were able to calculate the number of cysts the animals were eating, and they reckon they were eating at least 5000 cysts each a day for a period of 3 weeks. So that's a big infection.

And that's typically what you get is a massive, intake of immatures causing intestinal problems because the adults in the video seem to be quite well tolerated and don't seem to do too much. In terms of data, I mean, farmers are very disappointed that we don't know that much about them. There, there's very little data on clinical or production effects, any data there is.

It's pretty, you know, it's, it's pretty sketchy. Andy Forbes and, and colleagues did a study of an an abattoir in Nottingham, I think, a few years back, and showed that they had a rheum flu infected cattle had a significantly lower carcass weight and fat coverage, but the problem very quickly became working out what was actually happening because 90% of those animals also have liver sleep and then when you come to treat. With the product that we all know works against rhein fluid oxyclozinide, what are you actually treating because it's a liver fluke drug in its own right.

Farmers are convinced that animals improved dramatically after treatment, but most of the animals probably have liver flu as well. And if you ask, have you tested for liver sleep, they haven't, and so it's quite hard to work out who's doing what. And just to finish on a wee bit of epidemiology, around the snails for this one, we, we, we thought we knew what species of r fluke we were dealing with, but it was a thing called paranti stone servic circulates in deer and doesn't really cause much damage, but a bit of DNA sequencing, some special ones we got from SAC proved it to be a thing called calicoform or calicoer on doi.

We still haven't worked out how to say it. But it appears to be, it's, that's the dominant species in mainland Europe, and it might well have been introduced with some European cattle back in the day, but it seems to be very well established in, in, in Ireland and, and certainly in parts of the UK as well. It may be more pathogenic than from the survey.

We don't really know what we're trying to find out. We also thought it went through a different snail, a proper pond snail, so we only find it flooding events, but that doesn't appear to be true either. We've now found it and so have guys in Wales in our little Galba.

Mud snails. So sharing the same snail, sharing the same habitat, in many cases sharing the same host. So very quickly, I'm just conscious of the time marching on, in terms of practical control, and parasitizing the sheep that society and BCCDA itself here, think tank came up with a plan for farmers to try and simplify this, so linked to a typical life cycle seasons.

So we've been looking at pasture protection in the spring. We don't let the snails get infected. That's that strategic treatment to, to stop, egg shedding adults.

Summer will be about reducing the snail population. In the autumn, it's about avoiding the risk of ingesting cysts. And in the winter, it's a strategic treatment of animals that need to be treated with the right products at the right time and all of that stuff.

We're very lucky in the UK to have groups like Scots and the cars equivalent. We now work quite closely together on this. Animal Health Ireland also produced some really nice stuff, fact sheets.

And we have more and also do our own, and there's a fluke one on the left and this more recent one, which is a, a generic fluke worms and scab one because there are so many similarities about the diagnostics and treatments. So we're lucky to have those, I guess. As I say, cows is very good on, on fluke, liver fluke and rumen fluke, top 10 tips, scenarios and case studies for you to read through that might be more relevant to, to a practising vet.

We, we also developed a little animation which I'll just play the first few bars of, about like the fluke, which farmers find interesting and Despite this peaceful grazing scene, lurking within these animals and on the ground could be a nasty parasite. The liver fluke is a parasitic flatworm that can cause significant disease and production losses in grazing animals. I'll just stop it there because it's another 5 minutes, but just conscious that, you know, as I say of time, but just to finish and give you time for one or two questions, just to, we do quite a bit of talking to, to farmers and, and, and some vets as well.

But we are a research organisation and some of the research we're involved in, largely driven by our stakeholders. We know diagnostics for fluke isn't great, so especially the early. The early stages we we really struggle to diagnose that.

So we're looking at Things like can we improving the egg count? Can we do something with the couple runs and Eliza? We're looking at DNA-based testing through PCR and lab.

We're also looking at potential biomarkers in saliva as an easier sample than, than than faeces or blood. We've also tried to vaccinate against fluke, which is quite challenging. We don't have many vaccines against parasites at all.

Fluke is a very challenging one. If anybody wants to ask, there's a lot of reasons why. And you've seen even vaccines against COVID are not straightforward.

And also the environmental stages of fluke, and also things like silage and forage and pasture where the infectious stages can we detect those rather than just looking at the animals. So can we do a bit more with the snails and the cysts. Again, DNA-based methods, PCR, environmental DNA or potentially useful.

We needed to learn a little bit more about Roman fluke, and we've set up an experimental challenge model at Morden in sheep, so we can actually run infections now. And as I mentioned at the start, I think Sarah mentioned, I have an interest in the impact of fluke and other production diseases on greenhouse gas emissions. That's a very political one, livestock's role in the environment.

But just to, to finish on a and, and use the, the sort of banners we've been seeing a lot of recently. Take home messages I would always encourage, farmers and, and through yourselves to have a working knowledge of the fluke life cycle and to be able to risk assess, field or a farm for fluke. To understand what diagnostic tests are available and what they tell you about a fluke infection because they all tell you something different.

At different times of the year. Also know the fluke status of animals that the farmer is treating or not treating, and that's all around testing, not guessing or assuming too much and know which products work because many farmers sadly don't. Again, that's about testing and don't guess.

A lot of people to acknowledge for, for slides and information and help field work and lab work. So that's kind of hopefully where I'll finish and it should be a nice little slide that I'll leave here to advertise the next run of, of webinars. But I'm happy to take one or two questions and, and if we haven't got time tonight to answer them offline or online, whatever the correct term is, but I'll, I'll leave it for there and maybe hook up with Sarah to close things out.

Yes, brilliant, thank you so much, Philip. That was a really, really interesting presentation and a great insight there into a lot of the research that you've been involved with. We'll just give you a couple of minutes to, to catch your breath, and before we go to questions, can I just ask anybody that's, watching tonight?

You, you'll see that a questionnaire feedback survey has popped up in your, your browser. So please, could you just spare 30 seconds to fill that in for us before you leave us tonight. We do really value your feedback, and we do try and incorporate all of your comments when we're planning our next programme.

If you can't see the survey that's come up, then please feel free just to email us, at office at the webinarbet.com with your comments and your feedback. So we've got lots of questions that have already come in for you, Philip.

We're probably not gonna have time to go through all of them tonight, but we'll have a good stab, in the next 5 or 10 minutes, and then for anybody whose questions we don't get to, we will make sure that they are answered and that the questions are emailed round. So moving swiftly on then, a question regarding, liver fluke in the snails. You mentioned, snail infections.

So how do we determine whether snails are infected? And also, sort of the second part is, can snails pass liver fluke onto their offspring in the eggs, or do those offspring actually have to be individually infected? Yeah, that's a nice ecological question.

We, we're, we're lucky we can apply some science to the snail side of things. We can use DNA-based methods like PCR and lamp to amplify parasite, well, specifically liver fluke DNA and snail tissue. So sadly, the snails are collected and, and mushed, and we make an extract of that and use PCR and lamp to detect DNA.

You can see, and if you find the snails and take the trouble to dissect a couple, you, you'll probably find they're full of fluke stages. A lot of those flukes are not livestock parasites. They're parasites of frogs and birds.

So with PCR and lamp, we, we can discriminate and, and know exactly is it liver fluke? Is it rumen fluke, is it something else? So it's appliance of science, sadly, .

But it's, it's interesting to have a look under a microscope at what's, you know, quite often snails are infected, but they're, they tend to be parasites, birds and amphibians and other things. And in terms of infection, it, it's the mirrorsidium entering the snail's tissues that sets up the infection. The snail eggs do not become infected.

There, there is a, a, a very unusual, fluke parasite called the lancet fluke or diocelium that lives on certain islands off the west coast of Scotland and various other places. And it's got an am in its life cycle as well, so the snails actually shed. Infected eggs and the ants pick those up and then you've heard the story of the zombie ants and all that stuff.

They climb up to the tips of the blades of grass and wait for a sheep or a cow to eat them. So they, I, I can understand where that idea comes from, but with liver fluid, they short circuit that. We don't have that aspect in the life cycle.

So it's mereidium, infected snail, to carry into the animal. So I hope that answers that one. Yes, that does, thank you very much.

A question here, from Martin in Cumbria, he's seeing a couple of clients that are seeing adult fluke in six week old lamb livers that are going in fat for slaughter. And the abattoir reports are coming back, indicating that. Just wondering, is this due to a mild wet winter and infected snails surviving over winter, and just wondering whether you've seen this reported, in other areas as, as well.

And then following on from that, do you think that poor abattoir feedback is actually a missed opportunity within the industry, and how do, how do we drive more, more feedback? That's a very good question, thanks Martin. .

Yeah, 16 weeks is very early for, I mean, was that this was that this year or previous years? Yes, yeah, this, this year, I, I, I don't doubt that for a second, but I, I would have thought it was unusual this year unless you're in a very wet area, which I presume in Cumbria you are, as I mentioned, the dry spring and that very hot summer has kind of knocked things on the head, quite a lot even in the west of Scotland. So we, we haven't seen that.

We in previous years, Scots and cows. Individuals in those groups have been keeping an eye out. So you have people like Ben Struggnell who has seen his name here, looking at postmortems, you have people who are sheep specialists and cattle specialists keeping an eye out, just as a kind of sentinel group.

We haven't seen that, but I, it wouldn't surprise me that you get that on occasion, but 16 week old animals with adult fluke in their livers, I mean, for them to be that, for them to be adult, they must be at least 8 or 10 weeks old, so they can't have been grazing for very long. And as to where the infection has come from, that's a very good question. In a dry, a dry spring like we've had, I'd be surprised if there are snails that are infected and active and shedding fresh cysts.

The only possibility I think might be these are cysts that have carried over from the previous year, . And, and it's a very localised thing. You can have a little You know, just a little part of a field or a wet patch, even in a dry year, I mean, as you well know.

The the wet patches become where the lush grass is and if there's going to be any snails and cys around, that's where they'll be. So even in a dry year, animals can seek that out and inadvertently become infected, but that's very early to have, you know, 16 weeks of age to have adults look at them, that's early. Mm.

Yeah, we can, we can try and we can put a call out for for members to see whether other people are, are finding that too. Yeah, I mean, I mean that that'd be really helpful because I mean one of the issues we have is farmers assume that I, and we know exactly where fluke is across the country that we, we kind of get that information secondhand. The abattoirs are really important.

They're front line. They, I mean, to be fair, they, they haven't got a lot of time to look, but the adults look are but the most obvious thing to see, pathologically. At the abattoir and it's, it can't really be confused with too many other things.

Once you see the wriggly flukes, especially if, if you can, and I think Martin's right. If we could record that better, in some the abattoirs like we talked about Harbro do pretty good recording actually and it's all digitised, but it does involve somebody on the line taking the time to look. And that's maybe one of the reasons we didn't really spot rumen flu because because nobody looks in the room.

I mean, why, why would they? So that, that is maybe somewhere we could, we could do better, but it does involve. Intervention with the industry and that's not as easy as it sounds.

Maybe if we, if we start asking for the information, it might be, it might create incentive for them to, but it's it's invaluable information for the farmer to know that that batch of animals and they can track back where they treated. Well, I thought I treated them or well, maybe I used the wrong product or maybe a resistance problem I didn't know about, you know, where those animals come from? Are they some were they overwintered somewhere, you know, and that's when you start to build up the risk.

Assessment and that, that can really help. And I think that front line is, is pretty unequivocal. The other diagnostic tests have to be interpreted, you know, if it's a blood test, well, when was it taken?

If it's copper antigen, you could still have 7 weeks' worth of immatures there. If it's an egg count, you have 1210, 12 weeks. The liver could be full of immatures and you tell the farmer that's no eggs.

So, yeah. Yeah, the abattoir is a really interesting place to look, but it's, it's challenging logistically to do it. Just leading on, you've led us on really nicely to a few, a few other questions that have come in.

Just quickly, how do we determine if a farm has got triclobendazole resistance? Yeah, I mean, the first indication is usually a farmer puts in a routine treatment and Animals don't do well, and so the farmer's eye can be the first indication, but without testing, it's very hard to tell. The trilobendazole can kill down to very young flu, so 2 weeks of age and in cattle and 2 days of age and sheep.

And the only way really is to test it and you, the challenging bit is that you need a, a sort of a, you need a diagnostic signal. Either an egg count or a copper antigen level. And then you put the treatment in, and then did the treatment work?

So I mean there are times of the year when you don't have egg counts and you don't have copperrogen in the animals, so to try and do any sort of an egg count reduction test or a copper antigen reduction test would be a waste of time. So it's a challenge. I mean, we did, we did some work, in Argyle in the west of Scotland, which is kind of fluke central and we use sentinel groups of sheep that the farmer had identified 12 animals and marked them and we sampled them every 2 weeks.

And then we treated them when they got to a certain level, as I said, there's no point in treating them if they didn't have fluke. And there was no point in doing diagnosis if you didn't take a reduction test if you didn't have anything to reduce. So we followed them through the year and it was a, a, a low late year as we said, but it was still enough information to go in and put a treatment in 10 out of 10 farms trickle down all failed.

So that's pretty unequivocal. That gives you options then, you, you know, Trilobendazole is not going to work on that farm again, . It's a genetic change in the population.

It's in the snails now, it's on the ground. So you have to think about other options, and I think the farmers found that, I mean they suspected resistance. But I think they found it valuable to know that they had resistance.

It's been confirmed and now what do we do? So I, I don't think there's any easy answer to that other than test or do a reduction test, whether it's eggs or copper antigen, but you need a signal. And so that's usually done late in the year, in the autumn and winter.

Animals at housing might be an option to do that. I mean, we talked about treating them early doors. I mean, there's an option, do some egg counts or a couple ramps and when they come in, treat them then and take a sample a few weeks after and see what's happened.

It's usually 3 weeks after it's become the standard. OK, so that, that also leads into a question that's coming in about antibody elizer. So you mentioned there about the, the copper antigen.

Now, would, normal anti-elizer be a good enough test to see whether a flukicide has worked? Because how long after you've treated them, would you still expect to be, to be picking up, antibodies, you know, positive antibodies? That's, that's a good question too.

I mean, the antibodies tend tend to persist for a long time. I mean. Certainly months.

There, there are different versions. I mean, just like treatments, there are slightly subtly different versions of these tests, but they all basically look for the same thing. And, a, a successful flukide treatment won't knock the antibody level down appreciably.

It might dent it a little bit, but it won't knock it right down like you get with the faecal indicators. So I'd always be a wee bit wary of, I wouldn't recommend using a blood test as an indicator of, of treatment, . And I mean, the, the problem also arises, you know, older animals will have circulating antibodies.

They could have had a fluke last year or the year before. So a new infection doesn't really change things and, and it's very easy to get confused between a treatment that's gone in and now I'm getting a, a, an egg count or a copper antigen. But that's nothing to do with the previous treatment.

That's reinfection. The treatment worked perfectly well. So the, the antibody test isn't a great indicator for that.

I think its role is as a monitoring tool in sentinel animals and young animals. I wouldn't use it as an indicator of Treatment efficacy. Brilliant.

That's, you're you're leading into our next, questions really nicely, actually. So I'm going to, try and amalgamate. I've got 3 questions here that are along similar lines, which, are on the bulk, bulk milk Eliza test.

What level infection on a bulk milk Eliza would you advise dairy farmers to re to and treat their animals, mid-positive, high positive. Can you give some, some indication? Slightly thin ice there.

I mean, I would pass the buck unashamedly to people like Diana Williams who they developed the bulk tank test, and I, I wouldn't want to. Get it wrong, and it's all about, you know, the clues in the name, it's a tank test. It's, it's who's positive and how many, you know, is the test full of, you know, all the animals are moderately infected or you've got a couple of screamers in there and that's where I would, I would hesitate to give a figure and apologise for that, but, .

I'll need to go away and have a look at some of Diana's papers, but Diana would certainly be able to answer that as to where on that traffic light would you be worried about? Should, should I, should I repeat, I should, maybe I should know that, but I'd just be a wee bit wary about saying, giving, giving a glib answer. If you don't mind, I'll, I'll pass on that one.

No, no, that's absolutely fine. So also sticking with the, the bulk milk lisa and also, looking at animals that have never been outside, is it possible to still have, liver food in, in groups of cattle that have always been housed, which also links into can it stay. Infective in silage.

There's a comment here that how concerned should we be about, positive bulk milk samples in all year round housed herds, or ones which have occasional dry cows at grass. So, I suppose, can they, can they get it if they're housed all year round through silage or maybe zero grazed, ? That's a very interesting series of questions actually.

I mean. In an ideal world, they shouldn't, they should be out of harm's way. They shouldn't be infected.

But increasingly, I mean, we do hear farmers say that that the animals have never been out. Sometimes they get out for a day or two and that literally can be enough depending on where they go and what, what they graze on to pick up some infection. But, We, we've done some work on, on, infectivity and silage, actually making little, little silage clamps and putting fluke cysts in and seeing how well they survive.

And I know Liverpool have done quite a substantial amount of work on that, through a PhD student, it's a very nice piece of work. And I think the evidence would be that properly made silage kills fluke cysts. There shouldn't be.

Much infectivity and properly made silage now. What do you mean by properly made silage? Yeah, I mean it needs to be properly, you know, properly anaerobic and pH goes, you know, and it gets heated.

All of the things that happen in, in well-made silage will or should kill fluke cysts. We've done a little bit of work, as I say, if you put fluke cysts into, into acid solutions that would be of the same pH as a typical silage clamp. They survived remarkably well in that, so there's more to it than that.

It's about, there's no oxygen in there. It's, it gets hot in there. So if, if those things combined in properly made silage should kill flukeys, so they shouldn't be picking up infection from silage or forage or hailage.

I mean, ha hailage is another one, and, and hay, you know, how well dried is it? I mean flu cists do not like being desiccated, that will kill them as well. The properly made dry barn hay should, should be a low risk as well.

And I would never say never, I never say no risk. Hailage is a bit in between because it's a bit it's a bit green, it's a bit damp, . Yeah, that would be maybe a wee bit more risky, but as I say, silage and hailage properly made should be OK.

And another source we sometimes hear about is, is water and water syphoned off a flaky field becomes the water supply for the barn. That wouldn't be ideal. I mean, as I understand it, fluke cysts are not at the most infectious when they're floating about.

They, they try to stick onto hard surfaces, so they're ingested. But there's a possibility there would be one or two, in, in water supplies, so there may be, they may be sneak through the system that way, but housing animals should be. Pretty safe and out of harm's way, and That would be, you know, the ideal scenario.

OK, so maybe people are seeing, positive, bulk milk samples on house cows, then maybe to just investigate potential sources. I mean, yeah, it would be maybe investigate water sources and literally if animals are getting one or two days outside where, where are they going, I mean the same happens with worms. You can pick up a worm infection.

On a single day, and quite often and farmers will say, oh they've never been out and then you ask a bit more, well, go out for a week and sometimes it's not as watertight as as it might be. Brilliant. Well, thank you so much.

We have got questions, still to answer, but what we'll do is, because we've already run well over time, is that we will ask, Philip, just if he can answer those, offline, and we will email them round. So we'll make sure that your, your questions, get answered, because there are, there are more here for you, Philip. I'm afraid if I can.

I will pass them on to Andy Forbes and Diana Williams. Brilliant. We're, we're happy with that.

We don't mind. So I just want to, to thank you again, Philip. That was a really, really interesting talk, that you've done for us this evening.

You've covered an awful lot of ground and it's, given a lot of food for thought about how we're, we're treating and managing, fluke in practise. I'd also like to thank everybody who's attended tonight's live webinar. And just to let you know that we are going to be dropping down now to a monthly programme, from our, from our current fortnightly programme.

So, our next, webinar will be on Tuesday, the 11th of August, when we've got Joe Henry from Black Sheep Farm Health talking about weaning the the beef calf. And then our webinars. Going forward, we'll still be on Tuesdays and roughly, the 2nd Tuesday of every month.

And you can see there, we've got a great lineup right up until Christmas, and we're, we're now organising next year as well. So, I just want to say again, thank you very much, Philip. That was absolutely great talk.

Thank you for all your time tonight. And thank you and to everybody listening. Good night and stay safe.