OK, thank you, Antony. Welcome along everybody. So, as, as mentioned really, this is, a bit of an amalgamation of, literature review and experiences from, troubleshooting on, dairy units and calf rearing units, for really the last sort of 5 to 10 years.
The structure of the presentation really is going to be a little bit of background, we're going to focus on heifer rearing costs, but then we're going to spend most of the time talking about lostrum, nutrition, environment, and disease, and then just finish up really a little bit on on monitoring it at the end. So if we start off and look at heifer replacement costs and the the overall cost of production. Second only to feed costs, replacement costs, and if we just make small improvements here, we, we can have big impacts on the overall milk production costs.
So definitely worth focusing on, on this particular area. This is work that was produced by the RBC on behalf of Dairy Co. And they looked really at what the average cost for rearing a heifer in the UK was and came up with a figure of approximately 1800 pounds.
But you can see from the graph that there's a, there's a correlation between carving earlier and and a reduced cost for, for rearing. So we want to keep that in mind, as, as we sort of move on. If we take the example here of a 100 cow herd with a a sort of replacement rate of about 24%, and we use that heifer rearing cost of £1800.
You, you're gonna need, if you're calming down at 2 year old, you're gonna need 24 animals aged between 0 and 12 months and another 24 animals from 12 to 24 months of age, giving you a sort of total heifer inventory of about 48 animals. Now if we prolong the the age at first calving, you can see they're out to 27 and even 30 months, you can see the, the total number of heifers needed you know, increases, and those additional costs there you can see below. And, and these really do mount up significant costs to, to the farm.
So our overall objectives for rearing heifers, we want to be rearing them, and, and looking at that 2 year, 24 month age at first carving, but we don't want to compromise on body size. This is work done by Alex Back. In Spain, and he showed, this is over 10 years old now, showed that if we carve them down at a larger size, but at that younger age, they are more productive in the first lactation.
And our overall goal for heifer rearing really should be to optimise the future milk production of that animal. So maximising their genetic potential. So if we move on to, to Colostrum.
And, and really the Colostrum is, is, is hugely significant in, in calf health. It's, it's identified as one of the two greatest impacts on the future performance, but yet, despite that, we still see significant levels of failure of passive transfer on on dairy farms. I've been doing some project work this, this winter, across 3 farms.
I've sampled just shy of 250 calves in the last 3 months. And these are 3 farms that are chose for good calf management. And yet despite that, I'm still seeing nearly a third of animals with failure of passive transfer.
And we know that these calves that do suffer a failure of passive transfer are much more likely to get scour, much more likely to get pneumonia, and much more likely to die. So I, I would certainly, I'll just go back there and I, I, I certainly like to make sure that I have a clear understanding of the level of failure of passive transfer on the farm. And the best way of doing that really is, is to ask the carbs themselves, and the best way of doing that is, is blood sampling them and checking those levels of total protein in the blood.
Dan, I'm just seeing a yellow box that's appearing. On your slides saying please move this window away from the shared application. How do I do that?
I've not seen that before, so I don't know why that is there. Can you sort of move that? Will that move that have you?
No, when I When when I click on the the image, if I come out to the presentation, I might be able to. Yeah, it's just there, isn't it? So if you just want to start on importance of Colostrum again.
Yeah, so start from the beginning of this slide. Please, yeah, sorry about that, but it's just showing that rather annoying yellow box for some reason. Yeah.
So if we look at the, the importance of colostrum, it's been identified as one of the two greatest impacts on the future performance of, of the dairy calf. And despite this fact, we still find high levels of failure of passive transfer on farms. And I've been involved with some project work, this winter on on 3 farms that were selected for, for their good, calf husbandry.
And despite this, I, I'm finding levels of of a third of carbs with failure of passive transfer. And we, we know the importance of this really because carbs that do suffer from a failure of passive transfer are much more likely to get scour, they're much more likely to get pneumonia, and they're much more likely to die. So it's vitally important to get a good understanding of the levels of passive transfer on every farm.
And the best way of doing that is to ask the calves themselves through blood sampling and and looking at the total proteins that are absorbed. So if we move on and and look at the . Quality of colostrum, the key thing here really is that cholesterol IgG levels decrease by 4% every hour after calving, and this is just simply a dilution effect as more milk is produced and philtres into the udder.
But not only do we see a reduction in IGG levels, but we also see a watering down, if you like, of of fat levels, which are really important for for an energy supply for that calf, and also for protein levels as well. So the quality of the colostrum is very significant, and really the best quality is that that's taken soon after calving as possible. I do find claustrometers useful, but really just probably for freezing decisions only.
So if if they're not used in the right circumstances, they can be a little bit inaccurate, but if you're wanting to freeze down some colostrum and, and make a good decision as to what's good and what's bad, then they can be useful for that. If we move on and have a little look now at how much colostrum to give, and historically, people sort of talked about 10% of body weight over a 24 hour period. Or potentially just leaving the calf to suckle alone with the dam for, you know, a day or, or maybe 2 days.
And we just find that that's just inadequate really for, for good levels of passive transfer. So the advice now is to sort of moved on to sort of front loading and getting higher levels of lostrum in and quickly. So I sort of advocate 3 litres in the 1st 2 hours, with a sort of top up feed, maybe 6 hours of age or 6 hours after the first feed.
And there's a good reason for that really. First of all, you are front loading, you're giving a a large volume very, very quickly, but you're also giving a top up feed, which means that the stockman has got to go back and look at that car again a few hours later. So obviously if if cows are calving through the night, you know, it's, it can be difficult to, to then get, get access to colostrum and certainly having a frozen store of readily available colostrum is is helpful.
And I do favour these large surface area, foil type systems as opposed to the sort of big 2 litre Coke bottles that take a long time to freeze down, and a long time to thaw out. So if we move on and have a look at the speed in which the colostrum is is given, and a general rule of thumb, it's not 100% accurate, but it's a, it's a good rule of thumb. A calf will absorb approximately half of the level of IgG when it's given at 6 hours compared to what it would have absorbed at birth.
So, you know, that 1st 6 hours is absolutely crucial, and the, the, the gut is, is stimulated by the first feed, and will start to close down, and, and the amount of IGG that's able to be absorbed will, will therefore reduce. So be very careful of the the farmer who says that they like to allow the calf to suckle a bit, but if they're not happy that they've had enough, then they go in and tube feed later. And, and that's really problematic because in all likelihood, the, the calf will have responded to that suckling process early on.
The gut will have closed down, and then anything that's sort of tube fed later on, even if you give big volumes, the amount that's actually then absorbed is probably actually very low. So those cards typically, you know, can suffer from high levels of failure of passive transfer. So from a farmer point of view, the time that the colostrum is taken after calving and the speed in which it's given to the calf are the biggest influences that they, they can have.
If we now have a little look at the at the hygiene factor if you like, so the cleanliness of colostrum, and, and bacteria will directly compete with IgG for absorption on the mucosal surface. And given the right environment, bacteria will double every 20 minutes at room temperature. But if we drop that temperature down, and, and keep it in the fridge, Colostrum will actually be, be good for a a good day or so.
And if we want to further reduce bacterial contamination, then pasteurising it 60 degrees for 60 minutes, will do that. And you can see two plates there, one pre pasteurisation and one post-pasteurization. So really, you know, the, the tip here is clean a claustrum, you're gonna get better passive transfer and you're gonna get healthier carbs, which leads us on really to the .
The the farmer guidelines, and this is taken from AHI in in Ireland, Animal Health Ireland, and their calf care guidance, and this is just really simple, which is why I like it really, the sort of lostrum 123 for dairy calves. So the one refers to the first milking used for the first feed. The 2 refers to 2 hours within birth, and the 3 refers to at least 3 litres.
So the next topic to look at is, is nutrition, and er if we move on and have a little look at the, the impacts that nutrition can have. So we mentioned that Colostrum was identified as one of the two major impacts on future performance. And the second one is energy intake to weaning.
If we have a little look at whole milk and and what whole milk is made up of, there's a dry matter of about 12.5%. Which is why when we look at milk replacers, they're typically quoted as being mixed at rates of 125 grammes per litre, which is where that 12.5 figure comes from.
But you can see there that the fat levels and the protein levels, particularly, are much higher in whole milk than they are in in normal sort of conventional milk replacers, which gives a much more energy dense feed stuff compared to milk replacers. And just to put that into context, a fairly newborn calf weighing, say 45 kg, requires just over 300 grammes of milk solids, just for maintenance in a in an ambient temperature environment. And that's the equivalent of 2.5 litres of whole milk or 3 litres of milk replacer.
And that's just a standstill. There's no growth there, it's just what they need on a day to day basis. So if you have a little look at the milk replacers and and what's typically available, I'm not going to go into this in a lot of detail because we, we could spend a whole hour just, just on this one slide.
But I just want to pull out a few things here. There is a, there is a good paper which I've referenced there if you want to look at this in a lot more detail. But typically crude protein percentage is identified on the label, and, and whole milk will have a crude protein percentage of 26%.
So the closer you can get to that, the closer you are to to replicating whole milk. Certainly you don't want to be below 20%, and as I say, 23 to 24 and up to 26 is ideal. .
Protein is what's going to drive your skeletal growth, so if you want higher daily live weight gains, then you need to increase the protein concentration that's given. There is different types of crude protein that's available to carbs and but typically you'll see them branded as either skin based or whey-based. Now skim is closer to whole milk than than what whey is.
But, given a good quality, whey powder, you can actually deliver, similar, daily life weight gains as, as what you can with skin. You will typically find that skim gives them a glossier coat, but it, normally costs 200 to 300 pounds a tonne more. So, I question whether you get that additional 200 or 300 pounds return on that investment.
A measure of the quality of the protein that goes into the powder is given to you by the crude fibre percentage, and vegetable proteins can be used to bulk out, they're they're cheaper ingredients, but they're less digestible to the calf. But that tends to lift the, the fibre contents of, of the milk replacer. So you really want the the the crude fibre to be to be zero, and, and certainly anything over 0.15% you you're you're suggesting there that there's some vegetable protein bulking out going on.
The other one really to flag is vitamin E, and, and vitamin E is is an expensive ingredient, but it's crucial for, for immune competence, and we want to see levels of at least 250 milligrammes per kilogramme or international units per kilogramme. That's a minimum. So if you see levels that are below that, then that could suggest that changing the milk replacement could be beneficial.
If we have a little look at what's actually required to to get the growth rates that that you're looking for, I mentioned a a a feeding concentration of 125 grammes a litre. And if we fed that at 10% body weight, that would equate to 4 litres a day, so 500 grammes of milk solids. The calf needs 300 grammes just to stand still.
So in those first few weeks of life when it's very reliant on our milk solids for its nutrition, being a sort of pre-ruminant, you're gonna restrict growth in those animals. So we need to be upping the the volume and and potentially the concentration as well. So feeding 5 to 6 litres and feeding up to 150 grammes per litre, you can be pushing in closer to 900 grammes of milk solids.
And, and that really will support higher growth rates. If you want to be looking at growth up towards 800 + grammes per day of growth, maybe up to 1 kg of growth a day, then you really do need to support that with top end 26% crude protein. You can't just feed a lower crude protein milk replacer and just feed more of it and expect to get the the growth.
It just doesn't work like that. So if we, if we look at that concentration, if you could just move the slide on there, if we look at the, the concentration, just a word of caution there that to make a concentration of, let's say 125 grammes per litre, so a 12.5% dry matter.
You need to add 125 grammes to a litre to make it up to a litre, rather than adding 125 grammes, you know, in a litre of water, because that will drop your concentration to a, you know, closer to 11%. So make up to a litre, don't add a litre. In terms of room and development.
If we just move on In terms of rumen development, the, the major factor which is going to drive the development of the rumen on from just a milk solid only, nutrition, it is, is concentrates. Yes, roughage is important, but it wants to be. Of lower palatability, if you like, so that they don't eat too much of it, and it certainly ideally wants to be chopped.
There's an image there to give you an idea of what a good chopped roughage into a young calf should be. The concentrators are, are, are going to, produce volatile fatty acids, and it's those volatile fatty acids which are gonna drive roomum papillae growth. And, and those concentrates require a good deal of water availability to the calf, to, to help that ruum papillae growth.
So, the, the main take home here really is, concentrate intake will drive rumen development. So we need to look at our weaning process to to maximise concentrate intake. And, and I mentioned there that water was crucial to that, to the calf.
We need water availability to the calf from day one. Milk given to the animal, under all the stimulation of of feeding and and all of the noise that goes around it and the certain times of day, stimulates the calf and stimulates that esophageal groove to open and the milk then enters the Abemazin, it bypasses the root. And that milk is a feedst stuff, whereas if the animal is allowed to just drink water naturally on its own, quietly whenever it wants to, that esophageal groove will not be stimulated, and the water will enter the rumen and is a drink.
So just be aware of farmers that think that the water content within milk or milk replacers is sufficient to . To, to, to allow them not to be feeding water to the animal, water is is absolutely crucial for concentrate intake. If we want to maximise our concentrate intake when it comes to weaning, we need to look at a step down approach.
You can see the the graph on the right, matching up with the figures there on the left, showing that a step down versus a conventional, which is an abrupt weaning process, increases the amount of concentrates which the calf consumes. And typically we want to be looking at weaning the calf when it's doubled its birth weight. That's that's a general sort of good rule of thumb.
And, and that step down weaning approach minimises those growth checks, so we get a smoosmoother weaning. So if we now look at environment in which we rear the calves, we just look at what a building actually needs to do. So if we just move on.
Grand, so if we just look at what a building needs to do, we need to deliver clean, fresh air, that's the, the first goal. We need to minimise the buildup of moisture, and we need to protect the animal from, from draughts. Those are the three key things that any calf shed needs to do.
So if we look at the delivery of clean fresh air, it, it relies on outlets and inlets, and how this works is, is, is the stack effect. So the, the animal breathes out hot air and that hot air contains. Heat, it contains moisture and it potentially contains pathogens as well.
And we want to use the heat that that's contained within that air to allow that to rise and exit the building through outlets in the roof space, and that will create a negative pressure within the within the shed which then will draw in clean fresh air through inlets which are positioned below the eaves. And that, that whole circular, stack effect is, is natural ventilation. It doesn't rely on the wind, it relies on the principle of hot air rising and exiting from the building.
So if we don't allow it to exit through the outlets, then that air will slowly cool and it will coalesce back down and circulate and drop back down onto the animals. So we get a very quick build up of pathogens and moisture and heat within the shed. So if you have a little look at some examples of outlets and buildings, if you look at the image on the far right, the, the actual amount of outlets in the ridge there doesn't need to be a lot.
In fact, for, for young calves, the requirements are 0.04 metre squad of outlet per calf. Ideally it would be positioned fairly evenly along the shed.
But you can see images there on the left hand side where, you can use smaller volumes of outlet, but if you drive them with a fan to a suction fan to actually pull air up through it, then you can get away with smaller requirements. Just, just be cautious though that it doesn't just pull from the path of least resistance and just pull fresh air in from the side and then up out through the roof and actually doesn't it doesn't remove the dirty warm moist air that we we want to to to get rid of. In terms of inlets, there's varying different options available.
The image there in the bottom left is is something that we tend to see quite typically. It it's a, it's a farm building that's been adapted to put a few little stalls in to rear some cars. But it it's totally inappropriate for for what the calf needs.
There's no inlets, there's no outlets, and there's poor drainage, the only thing going for it is a low stocking rate. You contrast that to the image on the right hand side, where with a pen of carbs there with an air inlet in the door there, and this particular shed had a suction fan which drew that fresh air in through that inlet over the path of the carbs and helped to take dirty air up and out. And actually the, the air inlet didn't need to be significant, but it it it made a big difference.
We typically see in farms in the UK this vent air sheeting at the top there, which is less than 5% void. It's it's 96% solid tin, really, and certainly, over time it gets clogged up with dust and with cobwebs, so the actual amount of inlet reduces over time. If you contrast that to something like space boarding or what some people call Yorkshire boarding, then you, you'll typically see 3 times the amount of air inlet.
And then even better than that is, is the sort of gale breaker type material, the curtains, and, and they'll have a an air inlet space of about 25% void. 75% material, so you can see how over the same amount of space, you can actually get significantly greater amounts of air flow through the inlets on, on the shed wall. The image on the bottom there is another form of curtain that's made of plastic that can fill up plastic tubes that can fill up with air, so the farmer can raise the height of of that plastic very quickly, very easily and depending on, on the weather conditions.
The image on the left there is a negative pressure shed where the only inlets are those small little yellow lever type windows on the walls, so 1 per bay there. But it's been calculated to to suck out the air through the roof, so we get 10 air changes per hour, and that's absolutely ideal. So the, the air inlet wants to be twice, at least twice the outlet, and, and along each length of, of the building, ideally, preferable to be above the height of the animals so that you don't get a draught.
And when that's not possible, the only real solution to that is the use of mechanical ventilation. And I do favour these fan and duct systems. So you typically have a cow ridge which you can see on the left hand top image there, .
So that the fan is protected from external wind damage and snow, but it's drawing out clean fresh air. It's not up against another building, and the tubes you can just make out have got holes positioned typically at 4 and 8 o'clock on, on the clock face to deliver fresh air all the way along the tubes. And that means that we can set the amount of air that that goes into that shed so that we do get those 10 air changes as a minimum.
And even though it might be cold air that's coming in there, it's preferable to have clean, fresh, cold air that's pumped in in in this format where it doesn't create a draught. So at animal head height, you can barely feel the movement of air there, but we know that we're getting the right amount of clean fresh air entering that building. So the next thing that we need to look at is minimising the buildup of moisture in the, in the shed.
The, the, the main, things that we need to focus on really is drainage, and drainage is is very problematic, particularly in in sheds that are old or were not built for that particular purpose. And we, we need drainage of a one in 20 gradient under bedding. So that's a 5% angle, and, and to give you an idea, that that's the same sort of gradient that you would see in, in the disabled access into buildings.
So when you go up that sort of wheelchair ramp, that that's, that's the gradient we're looking at. So it's a fair, gradient to, to, to actually achieve. On sort of open passageways, 1 in 64 or a 1 or 2% drop, is, is sufficient.
So we really need to be thinking about where we position feeders, where calves are going to spend a lot of time and a lot of moisture is going to be deposited onto the ground to to help facilitate drainage channels or gradients where they're most needed. And in little hutch systems here you can see this, this farmer. Has just taken to putting a wooden pallet underneath the bedding and and they really, they remarked that the the difference in how dry the carbs were, and also that they used a lot less straw to keep them dry.
So anything that you can do to improve drainage is is going to help moisture exit the building, and it's not going to then evaporate up into the atmosphere and allow the the bugs to to survive longer. So the last thing that we need to look at is protection from giraffes. And, and particularly, this is relevant for calves under about 150 kg, where the rumen is, is not functioning to its full capacity, and they're not able to easily produce their own heat source.
So these animals are particularly prone to er er draught. And the the figures there show you that a newborn calf, it's lower critical temperature, so that's the temperature at which it starts to feel cold. It's about 9 degrees with with no draught.
And if you put a draught that's just a walking pace draught, so something that you could just about feel on your hand, it's not a a wind as such, it, it's just a light draught and and that significantly increases the lower critical temperature of that newborn calf from 9 degrees up to 17 degrees. So that calf is now feeling cold at air temperatures below 17 degrees, which is for most of the year, particularly where I'm from in, in, in Cumbria. And you can see though, as the calf gets a little bit bigger.
The effects of the draughts are less. However, it's still relevant 50 kg calf, you want to protect those animals from draughts where you can. So you.
You don't want to compromise your fresh air supply because fresh air will kill bugs, but you do want to stop draughts and and that can be difficult to to achieve on farm. You see from this image here. The calves, some of them have jackets on, and those are black and white calves, and the beef animals, the beef cross calves that have a bit more size to them, they don't have jackets on.
And that's one way that you can help to prevent from the effects of draughts, which moves us on to Compensating for the effects of, of a cold environment and there's several ways that, farmers can adapt to a declining er air temperature because if they do nothing they cannot expect calves to grow at the same daily live weight gain. You can see that in the graph at the top there. You need to make changes in order to achieve the same results consistently, because when the temperature is below the lower critical temperature of the animal, the animal will use feed energy to produce heat, and that heat energy will be lost to the environment.
And that's OK in the short term, but if it's allowed to prolong for periods of say 48 hours or so, then that will start to have an immunosuppressive effect. And it's the same for us that if we're cold and we're kept cold, then we will get a cold in in a couple of days' time and calves are no different. So the farmers got a few things that they can do to compensate for that.
So they can increase the concentration of milk solids, so maybe go from 125 grammes up to 150 grammes per litre, or they could increase the volume that's fed maybe from 5 litres a day to to 6 litres a day. They could increase the fat concentration of, of the milk replacer but typically it sort of maxes out at about 20%. So if they're doing all of those things.
There's not much else that they can do nutrition wise, so then the other factors are environmental factors. So increasing nesting scores, which basically is, is just more bedding, and allowing the, the calf to nestle down into a deep straw bedding, and that will have a significant effect, allowing them to stay warmer for longer. You can also use calf jackets and they're becoming more and more popular, and I'm certainly a big big fan of them.
Or you know those animals that are particularly susceptible to cold are sick animals. And the same with us, if we are sick ourselves, we feel the cold more. So just something simple as an infrared heat lamp to to focus the heat on onto the animal, over a sick pen is a very cheap and cheerful way of providing a heat source without having to heat up the whole shed.
OK, so if we move on and and have a look at disease and the impacts of of disease in, in calf health. Unfortunately, the situation in the UK at the moment is that, over 14% of heifers that are born alive failed to reach their first lactation. And that figure has sort of been bandied about in the literature for a number of years now.
And the main reasons, for that in, in UK, dairy farms is, is, scour and pneumonia, and we're just gonna look at both of those in a little bit of detail. So in terms of scour incidents in the UK it's very prevalent really. If you just go, just go back on just for a second, Anthony, thank you.
We, we see high levels of, of rotavirus, of, cryptosporidia, coronavirus, in fact, you know, when you see rotavirus, you often see crypto, hand in hand. And significant risk factors for that are self suckling, allowing the calf to stay with the dam, circulation of, of BVD virus on, on the farm, causing immunosuppression. And quite interestingly, and something that I, I certainly would support is no dedicated calf rearing staff.
So a clear correlation and risk factor between farms that don't have dedicated calf rearing staff and higher levels of scour. Just a point there, that there are non infectious causes of of scour, non-nutritional causes of scour. So something like a farm that feeds high levels of whey powder, high concentrations, whey powders won't produce an Abermasal clot, and subsequently the faeces can appear a bit looser, and that's not a scour that might be reported by the farmer as a scourer.
So just to highlight that. We move on and have a look at the impacts that scour has, and the pathogenesis of scour really is threefold. Firstly, it causes dehydration through fluid loss.
And a normal calf will require 4 litres of fluid a day for maintenance. But if you add in a mild case of scour, that calf requires an additional 10% of its body weight. So typically if you said another 4 litres of fluid.
So that calf now requires 8 litres of fluid a day, just to, to stay stay still. And then a severe case of scour where the, the animal is is potentially recumbent but sunken eyed, and they require an additional further 10% of body weight, so another 4 litres again. So that's 12 litres of fluid in 24 hours.
So a farmer that has a case of, of scour and and goes in with 2 litres of electrolyte solution and and expects that to, to solve the scour problem. It, it just, it's just not enough. So we, we really need to be aggressive with our fluid therapy, in, in, in the early stages to, to help support, the, the calf, and dehydrated animals, will be much less reluctant to, to suckle or, or to, to drink.
So just a top tip there really is if you are having to administer fluid therapy via stomach tubes, just make sure that the farmer has got a separate stomach tube that he uses for sick or scoured calves to the one that they might use to administer colostrum to newborn calves. The last thing you want to do really is. Is to be using a tube which has gone into a sick animal, to then go and administer colostrum to a newborn calf whose whose gut mucosal lining is open and susceptible to bacterial contamination.
So the second area of impact of scour is is acidosis, and that's through the loss of bicarbonate, as well as the buildup of, of L and D lactates. It can be difficult to calculate the level of acidosis, so really, you, you know, you just want to estimate the base excess deficits, on, on clinical signs. And a good example of that really would be that if the calf is, is still standing, but it's maybe looks a little bit dull or tired or has that wide-based stance that you sometimes see.
Then they typically require a supplementation of 20 to 30 grammes of bicarbonate. If they're wobbly or falling over, or you just give them a little push and they can't can't keep stood up, or they look a bit sleepy, slow blinking eyes, then they require 30 to 40 grammes of bicarbonate. And if they're down or flat out, then they need 60 grammes of bicarbonate.
And I have to admit that when I first started out I was probably not aggressive enough in the amount of bicarbonate that that I would give carbs, to, to replace acidosis. So the third area that we just need to look at is is starvation through damage to the gut papillae, and we see absorptive loss and carbs really need a good calorie intake and. When they scour out, the intakes drop and the gut is not able to absorb the nutrients, and we also see a loss of sodium in the scour, and that requires glucose to pump the sodium across the mucosal lining, and so we can also see a reduction again in glucose availability to the animal.
Through an active process of, of trying to correct the sodium loss. So it's absolutely imperative that we continue feeding, milk to scoured calves, and, and I see time and time again, farmers restricting milk intake whilst the animals scoured. So, you know, the glucose content of electrolyte solutions is very, very low typically and it's, it's really only there to facilitate that sodium resorption.
So just to summarise, scour control, the main things to to to focus on would be snatch carving, hygienic costs and transfer, good drainage in the bedded areas, so a dry, dry bed, protection against common things that that we typically see, such as rotavirus. There's some good evidence of ongoing cholostral feeding, providing a localised duct protection. Isolation of scoured calves, where possible and all in all out system, but good effective disinfection protocols as well.
So the second main disease area affecting that loss of heier carbs reaching first lactation is is pneumonia. And pneumonia is a multifactorial disease, whether it be RSV, PI3, mycoplasma, you can see in the bottom left hand graph there, RSV in the red bar, we typically see, see that 8. 5% of farms, PI3 in over 90% of cases, and, the blue bar there is is mycoplasma bogus, and typically we'd see that in 30 to 40% of units.
Although there, there is a much higher level seen in, in farms that use these multi feeders, the automatic calf feeders tend to see much higher levels of mycoplasma bovis on those farms. So if we have a little look at the control of pneumonia, and I've taken this extract from an article looking specifically at mycoplasma bovis, but if you, just ignore the first two points, which is only relevant to mycoplasma bovis, which can be excreted in milk and lostrum and transferred that way, the rest of it is is a very good summation of the, the control mechanisms for for pneumonia. So it's all about reducing airborne exposure, whether that be through good ventilation, low stocking levels, reducing exposure to sick carbs, so that's prompt identification of, of sick animals and prompt treatment, reducing the the fomite transmission.
Between animals and considering all in, all out protocols which we've talked about, and then looking at maximising the animal's defences against pneumonia organisms. So again, whether that's down to good air quality or reducing the pathogen load through vaccination protocols or removal of infectious diseases such as BBD, provision of good nutrition, which we've talked about, and addressing any other cholesterol management issues, which again we've we've discussed. And then minimising other stresses such as transport, cold stress, again, we've talked about those.
So there's a lot there, but really all of those can play a significant factor in reducing the levels of pneumonia. And I'm yet to really come across a farm that has zero levels of pneumonia. You can certainly get .
Very low levels of scour, but it, it's more difficult to get no pneumonia. And pneumonia has a significant impact on productivity. If we have a look at the, the impacts that it has on future productivity, the the table on the right shows the difference between carbs that have never had any pneumonia and calves that have had multiple cases of pneumonia.
And you can see that there's a a 5% reduction in first lactation yield and 10% reduction in second lactation yield. And this is work that came out of AFB in Northern Ireland. And, and similarly, work from Alex back again in, in Spain has recently demonstrated that carbs that have multiple cases of respiratory disease, that you can see in the bars there, survive less time in in production.
So the accumulated days in milk drops by over 100 days from carbs with no pneumonia to carbs with multiple cases of pneumonia. Which brings us on to the sort of hidden or unseen costs of, of pneumonia. And, and time and time again we, we hear farms sort of saying, oh, I don't get any pneumonia or I don't see any problems with pneumonia.
And the, the difficulty there really is that the evidence doesn't sort of back it up, and a good proportion of what a farmer would describe as healthy or non-clinical animals actually by the time they get to slaughter, have evidence of, of lung lesions or or pneumonia. And, and I, I sort of try and describe it to farmers in, in ways that they, they might understand a little bit better. So if you have a pen of 16 calves, and you reduce the weight gain by 50 grammes a day.
That's the equivalent of one less calf in in that pen when they're growing at 800 grammes a day each. So if you were to say to that farmer, you know, I'll, I'll take away a calf from that pen, they would, they would soon notice that impact on the farm, but they don't notice 50 grammes a day weight loss, and, and that's a very conservative estimate. It, it could easily be 200 grammes a day.
So, the, we know the importance of good growth in the early stages of life, and that the graph on the. The right there, again from Alex back shows that for every 100 grammes of additional daily live weight gain that the calf received during the first two months of life, so in that pre-weaning period, we can expect an additional 300 litres of milk in the first lactation. So we really need to grow those animals and grow them well in in the first few weeks of life.
And pneumonia will have a a a significant impact on that. So just to finish up on the disease section there, I'm not gonna go into lots of detail on on biosecurity and disinfection protocols, but this is taken from the dairy herd Health textbook of 2012, and it's a really good summary of, of biosecurity protocol. And farmers tell me time and time again that, you know, they clean out the the pens after each calf, but really, how many of them actually go to this sort of level, and this is what's recommended.
So wearing clean, protective clothing, removing organic matter. Washing the area with hot water, allowing that to soak for long enough, using surfactants, particularly surfactant detergents against biofilms, which can build up in the environment and help pathogen survival in the environment. The application of then the disinfection, disinfectant at the right concentration and for the right amount of time.
Rinsing it down with high pressure water and then leaving it to stand and dry completely. How many farmers really go to those lengths? So lastly, I just want to very quickly just touch on some monitoring, and, and really what what to measure, it is the first place to start really is.
So we've talked about age at first calving and the importance of age at first carving. You can see the graph at the bottom left there is is a number of farms, from a, from a practise, and you can see the variation in age at first carving between those farms. We've talked about the importance of passive transfer.
I apologise, the graph on the right's a little bit blurry, but each column there is an individual farmer and green represents calves that have had a good passive transfer and red calves that have suffered from a failure of passive transfer. And, and you can see big variations, you know, there's one farm there that where over half of the calves were actually suffering from failure of passive transfer and that that farm allowed the calves to, to stay on the dam for 36 hours, which, unsurprisingly, over half of them were not getting enough, colostrum on on that particular farm. The other thing to look at is growth rate.
I'll just quickly go back a step there. Growth rate to weaning, that, that's a really important one because that gives you a good indicator of, of the performance, through to, to weaning. If you've got good growth rates on farms.
Then, then typically there's not too many things wrong, but it's, it's a good one to highlight if you, you've got carbs that are averaging 5 or 600 grammes a day, then there's significant gains to be had. And then lastly, I tend to just look at mortality rates and morbidity rates. So, the percentage of carbs being treated for scour and pneumonia, .
Has been the sort of other significant factors to, to look at. So on the last slide here that you know, we, we would try to get farmers to to get growth rates and we would try to get them to measure scouring pneumonia rates where possible, although it's more difficult to, to get them to do that routinely. So there's a few other things there to measure, but really those are the, the, the main ones.
Age at first calving, levels of failure of passive transfer, growth rates, particularly to weaning, and levels of mortality and then and disease levels, particularly scouring pneumonia. So the, the last slide there really just is is a summary of of what we've, what we've discussed in the last sort of 45 minutes or so. I'm not going to go through those because we've covered them all off, but really, those are the sort of top tips that I I tell farmers if they're wanting to, to rear good, healthy, quality, productive, tip-top calves.
I Happy to take any questions. Right, if there are any questions, please come through with those. It's It's so interesting, you know, that whole common sense sort of animal husbandry, you know, let's make sure it's not too damp, let's make sure it's not too draughty.
The calves don't get too cold, is, is just so important, isn't it? It it is, but time and time again we see the same problems. And often, to be honest, farmers become very normalised.
Well, it's a human's a human factor. It's not a farmer factor. It's a human nature to become normalised to things over time.
And something which might appear draughty to me, the farmer thinks is completely normal. And so it's sometimes about just taking that step back and having a fresh perspective on the farm. And we've also talked a lot about, you know, antibiotic, resistance and so on.
We're going to be talking about that again at the virtual conference in a week or two. And again, the importance of that cleanliness, the good disinfection protocols, you know, if you're gonna have an all in, all out process, when you do clear them all out, that you really give the place a good clean before you get the next lot in. Well, when we look at antibiotic usage on our dairy farms, there's two main areas that we see high levels of antibiotic usage.
One is dry canotherapy and mastitis control, which is a big focus. But the other is, is in pneumonia control in calves, and, and there's significant management and environmental factors that you can do and that have a significant impact on the amount of antibiotics that are used in in calf rearing systems. And I think it's so good to see that we as a profession are year on year, we're reducing our antibiotic usage, aren't we really, because we're becoming a bit more cognizant of, of, of this, you know, these sort of things that.
You know, have been going on, but we're just becoming more and more aware of of the need for, you know, cleanliness and disinfection and so on. Yeah, I couldn't agree more. Dan, that's been great.
I can't see any questions, coming up, so thank you so much. I really enjoyed that webinar. I know I, I don't do cattle practise anymore, but a lot of it brought back happy memories from our first few years in practise and, you know, just seeing that, Some of those problems are a bit like, you know, I do dermatology and you see that the same problems do come up.
Sometimes it, it just does need repetition to remind people about it, doesn't it? Yeah, yeah, definitely. And, and having that fresh perspective, I think veterinary practitioners shouldn't be afraid to you know, open out and call in you know people for a second opinion on farms because I, I know myself, you know, you, you, you go to some farms on a very regular basis and you can be blinded sometimes to the obvious.
Yeah. No, that's really good, Dan. Thank you so much and hopefully we'll have you on another webinar before too long.