So, hello everyone. My name is Lautardo Rostol. I'm a faculty at UW Madison, in at the University of Wisconsin.
My role is primarily working involving immunology. I do a lot of research, on calf health and factors that affect the health of these animals and how from a management perspective, we can try to overcome some of these challenges. So, today we're gonna be talking about caution management and some of the new emerging concepts that have arised over the last couple of years, .
So, why is this important? So raising successful haifers, raising haifers successfully is a key aspect of economic sustainability of any dairy operation, and I think that it's more true now than ever, especially, here in the United States. That the price of heifers have risen substantially over the last 2 to 3 years, but they roughly represent 20% of the cost of a dairy operation.
And there are several factors, that affects the development of these animals, and it's not only important to think it in terms of how it affects, pre-weaning, mortality or incidence of disease or even growth rates, but it also seems to affect developmental aspect of these animals all the way to first lactation and cooling rates and how long these animals can last in a herd, so. Yes, several factors cholester management or diet, milk intake can affect health and growth rates during the pre-weaning, but it can also affect all the way up to milk production during the first lactation, how long they can last in the herd and things, and so on and so forth. So, why calves?
Are so susceptible to disease during these first couple of months of life. Well, these animals are born . Immunologically naive, so the immune system has not been exposed to any environmental pathogens, before, before birth and mounting an effective immune response takes time, and these animals takes even longer.
And therefore they depend exclusively on passive transfer of immunity through colossum. Also these animals don't, there's no transfer of immunoglobulins through the placenta during gestation as compared to humans that it does, so they receive. All those immune factors that are going to protect them against disease in the first couple of months of life exclusively through the colossum, making colossum one of the most important management tools that we have available at our hand to try to deal with some of this, this stuff.
And roughly, this is gonna be changing depending on your location, but roughly here in the United States, on average, we have around 5% mortality, around 35 to 40% incidence of disease on the primitive period. So How can we try to develop our clusterum management programmes so that we can get these animals on the right track from birth, so that we can expect these animals to to show their genetic potential when they grow up. So, what are some of the components that every dairy operation should have as an effective colossum programme?
There are several things to consider, but there are, in my opinion, 4 main pillars that are important that we pay attention to when we discuss, appropriate coossion management. So, how quick we collect the colossum from the animal after calving is really important because if we delay that process, colosum starts being diluted, so we affect the, the, the, the, the IgG concentration in there, but also, if we take too long to feed that colossum to our calves, the efficiency of absorption of that colosum starts being reduced. So even if we start with a colostum that has good quality, IgG absorption is, not gonna be optimal.
Another thing is how clean we collect the colossum. So things as our milking unit to collect the colostruum and the tubes attached to that, it's really important that we have, a protocol in place for clean, for cleaning that, those, for cleaning that, before and after, collecting the colossum. Also, the quality of the colossum, we'd like to see anything that is above 50 grammes of IgG per litre.
If we can go a little bit higher on that, that's probably even better. And then in terms of quantity, instead of defining as a specific volume, we try to advise in giving around 10 to 12% of their body weight. The reason for that is that the birth body weight of the cows is gonna be farm dependent, depending on the specific breed you work with.
This is gonna be different between Jerseys and Holstein cows, but if you work with any other breed, I know in, in, in Europe, there's, there's more than, there's more than that, and it's region dependent sometimes. So all of that is going to affect the birth body weight of these animals. And then we're trying to have something around 10 to 12% of their body weight.
In our herds, here in Wisconsin, having, birth body weights of around 40 to 45 kilogrammes at birth, we're giving roughly 4 litres, of galosum of at least 50 grammes of IgG per litre, so that we ensure that in the first feeding, we're providing at least 200 grammes of IgG. Why is this important? So, Effective passive transfer of immunity has been directly linked with incidence of disease on these animals.
And this paper that I'm showing here, it's, it's a paper that came out in 2020 that kind of like rearrange how we, what we consider effective passive transfer of immunity or . Yeah, good passive transfer of immunity and before, back in the day we used to consider anything above 10 grammes of IgG per litre or anything that was above 8.1 on the BRICS scale, to be, to be successful passive transfer, .
But when this paper came out, they reorganised the structure why we consider that in, in four main categories, excellent, good, regular, and bad, and then in the excellent category, it would be any animal that has more than 25 grammes of IgG per litre at 24 hours of age, and the equivalent of that in bricks is 9.4, and then we're trying to achieve. To have at least 40% of our calves in this category, and then good would be between 18 to 25 and regular between 10 and 18 grammes of IgG per litre, and here are the BRICS equivalents, .
The The recent, yeah, we'll just go here, . And if you're using If you're using a total protein at your facility, this would be the equivalence that, that you can use, right? So how do you measure this on farm?
You can use bricks reflectometers. That comes in many different flavours. This is an optical refractometer, where you put a sample of colossum in here and then you look through the optical, lens and it will give you a reading on BRICS.
There are some other digital handheld devices we just put a drop of colossum in there and it can give you the results either as total protein or in BRICS values. They both work well. I tend to think the digital ones are easier to use for farm stuff and they are a little bit more reliable, but they both work well.
The thing here it's important that we routinely check. For passive transfer in the calves, it doesn't have to be on every single calf in our farm, but it's important that at least we routinely check on our farm, to have an idea of where we stand with these categories of, of successful passive transfer. And also what I think it's really crucial is to check the quality of our colossum, so that we ensure that we're not only feeding an X amount of colossum, but that is also of, of good quality.
So for that, it's important banking colossum so that we know we have good quality colossum store so that we can feed to our cows. Why is this important? So, if we use So this is data from Michigan State University that they retrospectively looked at incidence of diarrhoea and respiratory disorders in calves that either receive 1 mil of colossum or 2 mLs of colosum in their first day of life.
And what they see is the calves that receive 2 feedings of colossum, they have less probability of developing a case of diarrhoea in the 1st 100 days of life and That is even more significant for respiratory disorders. So, feeding an extra meal of colostrum or feeding more colostrum to these animals. Provides an increased level of acid transfer to these animals and that is directly protecting them against these incidence of disease in the first couple of weeks of life.
Now, if we use the categories of successful passive transfer that I just mentioned to you, from that consensus review and then we look at incidence of respiratory disease and mortality and this is also from the same data from that herd in Michigan State University. What we can see is that calves that have achieved both excellent and good. Acid transfer, they have lower probability of developing respiratory disorders compared to the ones that only have, either 10 grammes of IgG per litre or they have failed acid transfer.
And then in terms of mortality. Calves that are above 10 grammes of IgG, . So both the fair, the good, and the excellent, they have lower probability of incidence of mortality compared to calves that don't, that have failed transfer of immunity.
What this is saying is when we used to use the, the threshold of 10 grammes of IgG per litre or 8.1 in the BRIC scale, that was good enough to keep our calves alive, and that's what we're seeing here, but to. Protect them against incidence of disease and so, and to keep our calves healthy, we need to go even higher.
We need to be about 18 grammes of IgG per litre and over to protect them, at least, based on this data. So, so why is colossum so important? And Colossum is not just about IgG or the IgG that is being provided in the Colossum, .
Colosum has many different factors that are important. And then when we look at the micronutrient composition, it has a higher protein content compared to mature milk, and this is mainly immunoglobulins, but there are some other non-IgG proteins in there that are important. It has a higher fat content and this is really important because calves when they're born, they cannot break down lactose that well.
The enzymes that degrade lactose, are not prevalent or very active in the 1st 2 to 3 days of age, so fat provides, . Highly concentrated energy source on those, in that first day of life, and then lactose content is actually much lower compared to mature milk and that seems to reduce osmolarity in the gut, prevents diarrhoea and improves nutrient digestion. And there's also vitamins and minerals that are important in there as well.
In terms of immunoglobulins, the main immunoglobulin present in there is IgG and this is another way of looking at this data that compares. Serum IgG concentrations in calves with the incidence of disease and we can see that there's almost a linear correlation between pathci transfer and incidence of disease On these animals. But colosum is not only IgG and nutrients.
Is packed with bioactive factors that are present in the colossum, as growth hormones, IGF-1 and insulin that are going to promote early development of the intestinal tract, and it promotes, functional development of, of several different physiological axes on the calves. It also has antimicrobial peptides in there that are important to prevent the growth of bacteria in the colossum and also to modulate how the colossum influences microbial colonisation in the gut of these animals at birth. It has several cytokines that seems to promote specific Function of the immune system of these calves in early life.
And when we feed fresh colossum, there are also immune cells from the mom that are present in the colossum that we know can cross the gut in the calves and might have some beneficial functions, and we'll talk a little bit more about that. So We had the question of, OK, what happens. When we freeze colossum and we lose these immune cells, .
Are affecting, are we affecting some of these other bioactive compounds as well and how that affects the development of the immune system of these calves, but also we, we're really keen on understanding how is colosum in itself, affecting the development of the immune system in, in calves in early life. So, we did the study, . Where we I haven't seen any cows.
Against salmonella doubling with a an SRP vaccine. 2 weeks before the dry off and 2 weeks after, to concentrate. Immunoglobulins in colossum against a specific against a specific pathogen.
And those antibody titers will provide a traceable signal from the cow into the calves, and then to the calves we feed either fresh colossum exclusively from its own dam. Or frozen colossum from its own dam. Or we fed no colossum at all.
And then we re-vaccinated those calves again at different time points with the same vaccine to see two things. Is Processing colossum affects the ability to provide some immunological memory to promote early responses to vaccination, and then colossum overall, how is colossum programming early immune development on these animals. So, This is some of the data that we, that we collected.
When we look at passive transfer, there is, no surprise that calves that didn't receive colossum, they have zero passive transfer, so there's no immunoglobulin at all in circulation in these calves, and then no difference between calves that receive either fresh colostrum or frozen colostrum. So, we'll be using. These colours and these abbreviations for the treatment, so this one is deprived colossum calves.
The violet one is fresh colossian calves, and then the pink one is the the frozen colossum calves. So, now when we look at the antibody titers against Dublin. Cows that were vaccinated, this is before the 1st dose, this is after the 2nd dose, they have a significant increase on antibody titers.
Against Salmonella Dublin, so the vaccination worked as intended. When we look at Colossum, that Colossum indeed contain antibody titers against Salmonella Dublin. And then when we feed it to our groups, what we can see is that both fresh and frozen calves, they have almost the same antibody titers against someone like Dublin, so there's no significant difference between these two groups, and the deprived group doesn't have any titers at all.
Then We vaccinated these calves at 7 days of age and at 28 days of age, and what we can see is the colossum-fed calves, both fresh and frozen, they naturally start declining their antibody levels. So this is what they received from colossum and they naturally start declining and then the. Deprived colossian calves doesn't, doesn't have anything at all despite being vaccinated, both at 7 days and 20 days of age.
Then what we can see is that the calves that did not receive colossum, they start responding sooner to vaccination. That's what you can see here at 42 days of age, and the reason for that is that colossum antibodies. And thou regulate B cell activation in, in calves, colosum-fed calves, and there's a biological reason behind that is to prevent unnecessary immune responses from the calf when it's protected by antibodies from colossum and that is believed to protect against unnecessary inflammatory responses to commensal microbes in the early, in the early period and then the calf it's protected by colossum.
Whereas in the meantime, calls on the prid cast, they start responding sooner because they don't have That inhibition that is provided by maternal antibodies, OK? Then when we go all the way to day 84, so we re-vaccinated these calves at day 70, and then. Now all the groups are responding to the vaccination after the 3rd dose, but colossal deprived calves because.
They did not have that innovation. They respond even further at the 3rd booster of the, of the vaccine. So, a couple of things in here.
We're not saying that you should not feed colossum to your cows, obviously, to get calves to respond sooner to vaccination. What we, what we're saying here, we're using this data to showcase. How in early life.
Even in the absence of antibody, mediated, reduction on, on B cell activation. Immune responses against specific pathogens. Take time to develop.
So what you see here in the deprived calves. It took almost a month and a half. To have What we consider we consider protective levels of antibodies against, against Salmonella doubling.
So when you're trying to protect your animals against a specific disease in the first weeks of life, You need to vaccinate the dam so that the dam can provide those antibody titers in the colossum and provide it to the calves, and then the calves will have passive transfer of those specific titers and hopefully it's going to protect it against disease and then. Slowly those animals will start developing their own immune responses, but that is going to take time, . So that's, that's what we're trying to say, to say with this.
So Now, what happens to The rest of the immune system and how colossum is controlling the trajectory of how the immune system is developing and what we can learn from that, from this study. So, if you remember we said we had calves that were either fed fresh or frozen colossum or they were not fed any colossum at all. And something that I, that I missed.
Mentioning is that we kept these calves in a bio safety facility to reduce pathogen exposure so these calves would be able to remain healthy. If we were to keep deprived calves in our farm, at the university farm, they would die in the first couple of days, most, most likely. So all of these calves were healthy, they were maintained in a facility, and we were interested in just looking at the effect of colossum in programming early immune responses.
So, we saw quite a few interesting things. Most of you watching this webinar are probably not familiar with the different T cell populations on, on calves and what, what do they do and what they are important, but know this, the gamma delta T cells. Are the main lymphocyte subset in circulation in calves in the first couple of weeks of life.
And they are very, very important in providing a first layer of defence against environmental pathogens. They become activated really fast, . And they can respond much sooner than other T cell subsets.
They can coordinate immune responses and it also seems to provide tolerance to commensal or environmental microbes that don't produce any harm to these animals. So these are really important immune cells and we were particularly interested in this because we saw some preliminary data in another study. That suggested that colostrum promoted the expansion of these gamma delta T cells, so promoted these cells to, proliferating and being more activated, so we were interested in looking at that.
What we actually see is that, All the calves, even though the prime ones, they have an increased on gamma delta T cells. After 48 hours after being born. But then somehow the calves that receive colossum, either fresh or frozen, they are able to maintain the levels of these gamma delta T cells.
For much longer compared to the deprived group. So, in the deprived group, that environmental exposure to microbes in the environment seems to promote the increased expansion of these gamma delta T cells in circulation, but they gradually start to decline, whereas the cows that receive colossum, they maintain them stable for much longer. And Then what we see is that colossum deprived calves.
They start to compensate with some other subsets of T cells, so they compensate that decrease in gamma delta T cells with increases on on T helper cells and cytotoxic cells, which is probably not the most ideal responses on these animals, and we have some other data that suggests that these . Direct responses to overt inflammatory responses that ultimately are not, are, are not ideal for, for these animals. So, colossum in early life is restructuring the reorganisation of the immune system towards a function that both protects the animal against specific disease in early life but also promotes tolerance to environmental microbes to prevent unnecessary inflammation.
That's what we think is going on in here. When we look at other subsets of the immune system, here we're looking at macrophages, and this, we're looking here at a particular subset of macrophages that are very inflammatory. We see that calves that don't receive colossum, they have an increase in the population of macrophages, and then those macrophages are much more inflammatory.
OK. And then When we look at neutrophil function on these animals, so these are immune cells that we isolate from blood. We take blood samples at different time points in these calves, we see.
A tendency, For these neutrophils to produce more reactive oxygen species. This is one of the mechanisms neutrophils can use, but it's a highly inflammatory process. And then also the deprived ones to have more activated neutrophils.
So what we're seeing is two things. Colosum is down regulating, neutrophil activation against probably to reduce, excessive inflammatory responses. Since these caps are being protected by, by colosum, there's no need for this excessive activation, and then in the meantime, the immune system is kind of like figuring out.
What it needs to react to, and then what is just a normal commensal member of that microbiota, whereas the deprived group is highly reactive. So Kind of like overall what we're seeing is that colossum is not just a source of immunoglobulins to provide that initial passive protection, but The host of other . Bioactive factors that are present in this colossum are specifically fine tuning how this immune system work.
So, another question that we have now is, OK, if all these bioactive factors that are present in the colossum are very important, for proper function of this immune system in early life, then how processing the colossum. Can affect . It's functional capacity, .
We saw in our study that freezing colossum doesn't seem to affect it that much. So, at least in the variables that we look at, The maternal immune cells are not providing a very specific function, at least that we understand. And in previous studies that have found fresh versus frozen.
There's also not a clear benefit in incidence of disease in these animals either. So at least for now, we don't have very clear evidence indicating that we should be feeding fresh colossum. And it's important, as I said in the beginning, That we have on our farm, colossum protocols that allows us to bank colossum of good quality so that in the case that we don't have either enough colossum or good quality, we can rely on that to feed our calves.
So, going, continuing with this, this is a really interesting study that, was done by Sabine Mann's group, out of Cornell that they simply collected, colossum on sterile conditions from, from a cow and then. They process that colossum in different ways. They either kept it raw, so kept it at 4 °C for less than 20, for less than 20 hours, they froze it, and then re-thaw it, or they pasteurised the colossum at 60 degrees for 1 hour, then.
They inoculate that colossum on a plate and then saw how, A specific strain of Escherichia coli would grow on those environments. So they monitor the growth of Estherchocoli either in raw colossum, in frozen colossum, or in pasteurised colossum. And it's really, really interesting what they observe is that.
In the colossum that was heat treated. That is this one in red. E.
Coli grew much more than in Colossum that was either kept. Raw or colossum that was just frozen. Meaning that That pra colostrium at this temperature for, for one hour might be destroying some of these.
Antimicrobial peptides that I was mentioning before. That are there to prevent excessive bacterial growth in the colossum, OK? So, Kind of like a main take from this is that if you are pasteurising colossum.
That this is an important tool a lot of farms rely on to reduce pathogen load in your colossum. You should be cooling that colossum down immediately to avoid microbial growth in that environment because it seems to be more susceptible to microbial growth, . Probably because some of these antimicrobial peptides are being affected.
So, let's move on. One of the other pillars that I mentioned to you that were important in colossum management is quickness of feeding of that colossum to the calf, and we said that within 2 to 6 hours, . Is what we will recommend.
This is a study that all the cows were fed the same source of colossum, so the colossum that all these calves received was exactly the same, was a colossum replacer and all of these calves were either fed at right at birth within one hour of being born. 6 hours after birth or 12 hours after birth and then they monitor. Immunoglobulin concentrations in circulation of these calves at several time points all the way to 48 hours, of age.
And what you can see is that calves that receive colossum, much sooner, they are able to absorb immunoglobulins much more efficiently compared to calves that receive it at 6 hours or at 12 hours of age. And this is really important because we can start with a colossum of really good quality, but then if we take it long enough to feed it, that calf is not gonna be able to absorb those immunoglobulins as effectively. So, if we do the exercise of looking at this consensus recommendations that I showed you before, If we feed after 6 hours, even if it's a good colossum, we might go from an excellent passive transfer to a good one and.
If we plot that into our linear regression that I showed you before between serum total protein or serum IgG and incidence of disease, this would be equivalent of an increase of 1.5% of mortality and 5% more morbidity or incidence of disease. So it is important.
I know in every farm scenario is different, but at least that we try to feed couption to our cows as soon as we can. Because if you do so, those calves are going to absorb immunoglobulins much more effectively, and they're gonna have increased passive transfer of immunity, and then that is going to protect our calves much better, than if we, that if we delay that feeding. We have, we get a lot of questions from farmers of how we should be feeding our calves, .
And we should either bottle fed them or tube them. So this is an older study, but a really interesting one that they fed colossum to calves either by bottle in calves that would drink 2.5 litres of colostruum or they tube the same amount to these animals and then they put them under an X-ray and then they look where the colossum is going.
So, of course, calves that were bottle fed. Esophageal groove, got activated so that colossum bypasses the rumen and goes into the abdomasum which is forming a curd, whereas the cows that are tube fed, that colossum seems to be distributed into the, into the rumen. Now, is that important?
Well, it seems like, it doesn't really matter. So, this is another study that colossum is either bottle-fed or to, to calves, and then all the cows receive the same amount of colossum of the same quality, and passive transfer immunity is exactly the same. They also added a marker that is called acetaminophen, that is to look at passage rate of that colossum from the stomach into the intestine for absorption and passage rate is also exactly the same.
So, the main recommendation we give to farmers is You should focus on getting that colossum into the calf as quickly as possible. And there are a lot of calves that are not going to be, they're not going to drink, that 10% of their body weight, especially in, in, in bigger, in bigger calves that are 40 to 45 kilogrammes at birth. We, we do tend to see a lot in our, in our university farm.
So, we recommend tubing that caution to these animals so that you ensure that with the first feeding, you're providing the specific amount of IgGs that animal requires to have successful passive transfer and hopefully protect them against disease in these first couple of weeks of life where they're really susceptible. We also get a lot of questions from farmers on how we can get cows to produce more colossum. So, It is, it's actually pretty difficult.
There's a lot of information out there from a nutritional standpoint, . That doesn't, there doesn't seem to be a really clear answer. One of the main things is energy concentration in free fresh cows seems to have a small effect on yield, but it's probably not beneficial to be feeding, .
High energy diets to our prepartum cows anyways. But this was an interesting study from, also from Sabine Mann's group that they use oxytocin, either 40 international units or 20 international units of oxytocin at birth, and they saw that it did have an effect on yield in primeorous cows but not in multiparous cows when they received 40 international units at birth. And it had no effect on IgG concentration or total IgG.
And that was also not affected by parity. What it seems to be happening here is that high doses of oxytocin likely overcame the impaired, milk letdown that sometimes can happen in heifers when they're milk for the first time rather than altering any of the colossum composition or, or IgG transfer. But it might be beneficial if you see on your farm that you're having some trouble into getting colostruum letdown.
On your heifers to implement this practise on your farm. Another thing that has shown some, some promise is the use of supplementation with choline on your prepartum cows. So it's, it's common here in the states to feed choline to our prepartum cows on the, on the pre-fresh, on your pre-fresh cows, so 21 days before calling to 21 days after calving, and that seems to have an effect on cholosum yield.
Without affecting immunoglobulins. There is another study that also shows that arginine, ruin protected arginine might have an effect on colossum yield and, yeah, on colossum yield, but this is just one study that have shown this in very specific, conditions. Another study that is quite interesting that was published this year in the Journal of Dairy Science, this is from a group from Uruguay, that they categorise cows at dry-off based on the Total amount of somatic cell counts between low somatic cell counts, cows and high somatic cell count cows and it was quite interesting that they saw.
That the cows that had high somatic cell counts. At, at dry-off, they had lower IgG levels, like lower IgG concentration compared to the cows that were low somatic cell counts at dry off, seeming, like there's something that happens in the reorganisation of the structure of the mammary gland when those cows have high somatic cell counts that somehow it's affecting claustrogenesis. Which is pretty interesting.
And even more interesting than that is that the calves born to cows that had high somatic cell counts, they had lower passive transfer of immunity regardless of the casum that they were being fed, OK? So they were fed colossum from high somatic cell count cows or from low somatic cell counts, and they still had lower passive transfer compared to the cows, the calves that were born from low somatic cell count cows. So I think this is something that is important to start paying attention to in our farms, that is our dry cow therapy, and how we dry those cows in order to avoid drying cows with high somatic cell counts, which inadvertently might be affecting colossum quality and might also for some reason be affecting, passive transfer of immunity in our calves.
Lastly, another factor that seems to affect colossum quality is heat stress. So, this is from my colleague, Doctor Jimilla Laporta here at EW Madison as well, and she noticed that when cows are heat stress during the dry period. Those .
Sorry, when, when calves are heat stressed in utero, so cows are heat stressed, and then the cows that are in the uterus of those cows, those calves seems to have a lower efficiency of absorption of immunoglobulins compared to calves. That receives some form of. Of cooling during the dry period, of in, in this cows.
In this case, was fans and, and, and sprinklers to provide a thin moist of, of water on those cows and In this graphing here, we see the serum IgG concentration and we see that. In these groups, all the calves receive the same type of colossum. In utero cool calves, they have higher passive transfer of immunity.
So this is also, if you are in a region that have heat stress during the summer months, high THI during the summer months and your cows are in heat stress in that dry period, this is something you can pay attention to, to try to reduce. So What happens if you don't have enough colossum or good quality on your farm? Colostruum enrichment with, colossum replacers can be a good tool to increasing at least the total amount of IgG that you're feeding to these animals.
So, what I'm showing here is a study that was done in Canada by Mike Steele's group helping Guelph, where they collected colossum either from a very low quality, colossum from, from the dams, colossum of good quality, so 60 grammes of IgG per litre. Remember we said that anything that is above 50 grammes of IgG per litre is something that we consider good. Or of really high quality of 90 grammes of IgG per litre.
So these three are exclusively maternal colostruums of low quality, good quality, or high quality. They checked this with a BRICS refractometer and then what they decided to do is feed this colossum to calves, and then this is the passive transfer of immunity that these calves, got. So they received 10% of their body weight, so roughly between 3 to 4 litres of colossum, .
The low quality, barely above the threshold of what we consider fair passive transfer. The good quality had, the good quality and the high quality had excellent passive transfer of immunity. So now, when we enrich.
This low quality caution. Maternal quality colostruum with a colostum replacer. You can increase total passive transfer, .
Significantly improving passive immunity on those calves, so what they did in here, they increased, they enriched this colossum to take it to 60 grammes of IgG per litre. To make it similar to the 60 grammes of IgG maternal colossum, what you can see is that even though you enrich to 60 grammes of IgG with colossum powder, the passive transfer is not the same. OK, but at least it's enough to increase positiveive transfer to a number we would like to see those animals to be.
Now, if we have a good quality colostrum. Good maternal, calcium of 60 grammes of IgG per litre, in this case, this one, and we try to enrich it to take it to 90 grammes of IgG per litre, there is no added benefit in there. There is only a marginal increase in passive transfer, so we don't recommend doing that.
But what you can do is that if you have a very low quality colossum and then you don't have a colossum banked. To feed to these animals, you can enrich that colossum with a collagen replacer, and that those calves are gonna respond with an improved passive transfer of immunity. With, with that, I hope you take some beneficial ideas, to your farm or to your clients that you can try to apply.
So remember Colossum is not just IGG. And it's one of the most effective tools that we have at our disposal on farms to get animals to be protected against disease in this pre-weaning period, but also seems to be affecting how the immune system develops early in early life and maybe making those animals be more protected against disease throughout the entire, productive life. So with that, thank you.
