OK. Hello, everybody. Thank you for joining us at the webinar VET and thank you very much, Rebecca Min for inviting me to give this talk.
Brief, sort of introduction to myself. I'm Peter Platter. I worked 27 years in, in general practise, first in Germany, then in the UK where I moved over 31 years ago.
And then joined the Royal Veterinary College eight years ago, where I teach final year students at the extension service in the south of England near Dorchester. And so do a lot of teaching, but also do research and advisory work. And my main research interests are mastitis and, and calves, on, on calves, especially, iron deficiency.
Anaemia. So this whole concept, iron deficiency in calves, I've never heard of this until probably 8 years ago, when I went to a congress in Germany and somebody outlined this, and then I noticed in Germany, they're actually quite keen on the subject. And then I started a bit of research in the UK and became more and more interested in this.
And yeah, this is basically the A bit of a summary where we are now, whether we should be worried or not. So fictional reality is the question. Does it actually exist?
And, yeah, I'll give you some, indicators, for and against the, the concept, yeah. So, we will talk first about the functions of iron in the body. So what does iron do?
We know, obviously, we all know a few of them, but some of them are less known. We talk about how is iron actually regulated in the body because there's a specific feature for iron, which is different to other trace elements. And yeah, what do we actually see on a herd level, if there is iron deficiency anaemia in a herd?
And then how, what tools have we got available to diagnose iron deficiency anaemia, mainly on a herd level again. So I'm not so much talking about the individual anaemic calf or cow. This is a different subject.
This is basically, iron deficiency anaemia as a herd problem. Yeah. And then we look at some other species.
We all know about pigs. Obviously, pigs all get ironed, if they're red indoors. So I'm not talking much about pigs, but there's also some work on, lambs and goat kits, available.
And, and, yeah, I will go into this as well because there's a nice comparative aspects to this as well. And then finally, obviously, what can we do to, to treat or mainly to control iron deficiency anaemia if we think it does exist. So what do we actually do in practise?
So that's just a hands-on advice, basically. Yeah, so. OK.
The rolls of iron, What we all know is obviously the haemoglobin and the myoglobin. Yeah, it is part of those molecules, essential component of hemo, which then make up the haemoglobin, which is a, basically, set up of, of 4, single molecules and myoglobin, which is a single one. Both contain iron, both bind oxygen, one in the blood in the red blood cells, and the other one in the muscle cells.
More iron is actually much more stored in haemoglobin and myoglobin. So this is what we all know. So we almost make, iron and haemoglobin almost synonymous, but, but they're not really.
Yeah. So. What is less known is that iron is also part of some antioxidative enzymes.
So, for example, iron deficiency can, induce oxidative stress, including onto the red blood cells. So, these guys from, from Iran, they found out that, not only does iron deficiency anaemia reduce the number of red blood cells in the blood and the, the generation of them. But it also reduced the survival time of life expectancy of red blood cells, which is due to oxidative stress.
So iron deficiency can reduce oxidative stress. And iron deficiency is also, so iron is also involved in many levels of the immune system directly beyond its role on, on haemoglobin and oxygen carrying. So, so again, nitric oxide, it's also important for antigen-specific, lymphocyte.
proliferation. With a caveat that excessive iron or free iron, can also lead to oxidative damage. So we need the optimum concentration and iron in most parts of the body is bound to something, bound to some proteins, to not, to, to cause it, not to, to prevent it from causing oxidative damage.
Yeah. There are also some other direct effects of iron. So it promotes intestinal development, and this is fairly instant.
So again, this is not linked to haemoglobin. This is not linked to myoglobin. So it's, it's a direct effect as well.
This is all research from piglets, so, so which is obviously much, where iron supplementation is much more important. And they also could find they, it favours brain development and it favours spatial recognition and piglets. So there's some, some extensive research in this, where iron has got a direct effect on other parts of the body, which are much, much less known than the haemoglobin myoglobin aspect of it.
so there are multiple functions of, of iron in the body. On the downside, there's also a concept, and I get to this in more detail, that iron is obviously not just a nutrient for mammals, for the organism, for the calf, for the lamb, for the piglet, and for us. But iron is also a potential nutrient for pathogens.
And there can be a conflict of interest which I go into in in more detail as well. So how is iron then regulated? Most iron in the body is actually retrieved from recycling dead red blood cells.
So red blood cells at the end of their lifespan are taken up by macrophages. And these are then, these then take the iron out again, transport it to the bone marrow where it's then used for new haemoglobin and, and red blood cell, synthesis. So, the iron uptake from the diet is only sort of the 25th of The iron which is recycled.
So this is the source of iron is mainly internal and, and not so much external. So, but let's talk about the uptake of, of dietary iron. So after passing the other ma, most iron is trivalent iron, so 3+.
The gut can only take bivalent, so 2 + iron. So iron is in the gut, reduced to bivalent iron via vitamin C, cysteine, or enzymes, at the gut wall, basically. So, so and this this bivalent iron can then be taken up into the enterocyte.
Again, free iron is toxic, so it's, it's quickly bound onto ferritin inside the enteroy. Or it can then pass on to the bloodstream and bound to a binding protein called transferrin. Yeah.
And this whole uptake of iron is not a passive process. There are specific channels in the enterocyte. And the number of these channels is regulated by a peptide hormone which is produced in the liver, which is called Hepsidine.
It is essential, it's a central molecule in regulating the whole iron status in the body. So if there's iron deficiency, under the influence of Hepsidine, there are more channels in the enterocyte to take up more iron. It So if, if there's some iron surplus or or, or this iron status is sufficient, then Hepadin is decreasing, and there will be that will be No, sorry, Hepidine is increasing its If there's more, if there's more iron, and so yeah, it don't regulate directly the iron in if the status is high.
But it also down regulates the iron uptake into the body if there is infection or inflammation in the body. So, and, It can also not only down and up regulate, it also redistributes iron in the body. So if there's hepidine is high, then, this iron gets distributed into macrophages and then making it less available to, to extracellular pathogens.
So iron is the only known trace element which we know about that is regulated by a hormone which does not only respond to the nutrient status but also to infection status. So hepidine is essential in down regulating iron uptake in the presence of infection, so iron depletion is actually a mechanism. To fight pathogens.
So this is from a human article, a nice review article, how this works. So, again, summarising the most important aspects here. So, a trivalent iron, with an enzymes, into bivalent, this can then be taken into the enterocyte.
And, and these channels, on the enterocytes, they are hepcidin dependent. This is produced in the liver. So, and Hepsidine is synthesised in response to, to iron and in response to inflammation.
Yeah. And then the iron can then go into the bloodstream, bound to transferring, and then going into the muscles, into the bone marrow, get produced into red blood cells, red blood cells at the end of their lives but are taken up by macrophages again. And the distribution of iron into mrophages is again Hepsidine dependent and as I said, hepsidine, synthesis is dependent on the iron status and also the infection status of the organism.
Yeah. So to summarise, if the Hepadin status is low, then there will be more iron. In, in serum, if the, more in haemoglobin and less in macrophages, and the more in hepatocytes and vice versa.
Yeah, which means for the hosts. Immune system. There is an optimum iron balance.
Yeah. So if we have not enough iron, We know that iron is important for immune functions. So we have issues with the host immunity.
If we've got too much iron, we may feed pathogens. And we again have an issue with host immunity, which may get overwhelmed by these pathogens which are fed on iron. Yeah.
So this is all Hepsidin regulated. So hepsidine decreases, serum iron, decreases dietary iron absorption and increases the distribution towards macrophages. Again, depending on iron status and depending on the infection status.
So that's quite a crucial thing to, to take home and to understand everything we are doing to animals. In addition to this, this is again human work, . Iron can affect the gut microbiome.
So oral iron supplementation in people has shown that there is an increase in potentially less desirable bacteria enterococcal, and so on, and the decrease in these beneficial bacteria, you may recognise some of these there are in probiotics. So Lactobacillus and bifibacterium, for example. So it shifts the balance, in the gut lumen as well to, towards less desirable bacteria and can even increase, true pathogens like salmonella, shiella, campylobacter, and, and ytobacter.
So this is another aspect. Yeah. So, again, .
We have to have a, the right way of supplementation, and, we need the optimum supplementation and, and not over supplement, because otherwise, we may get these infections and we basically feed more of the pathogen than we feed the calf or the lamb or the piglet. OK, now, what is actually the iron supply and demand in the pre-weaned calf? So back from the theory to the, to the actual animals.
So iron deficiency anaemia and thoughts about iron supplementations. Have been, have been described for a very long time. So middle of the century, some, some even earlier than that.
So this was Journal of Dairy Science 1963. So it's, it's known, it's well known that, this is sort of, that there's a potential there. Yeah.
And the whole, basis of the concept is that whole milk. Contains only 0.5 milligramme of iron per kilogramme of whole milk.
The NRC recommendation for iron uptake in a six week old dairy calf is set as 135 milligrammes. So there's no way. This can be met via the whole milk.
Yeah, so, . If you do a bit of back of envelope maths, it means the calf would have to drink 270 litres of milk per day to meet its iron demand as stated by NRC truly from whole milk, which is obviously impossible. So whole milk is a risk factor for this.
And then It in recent times, we have organic farms, they require whole milk feeding practically for a period of 12 weeks. But also in the non-organic world, we recognise the increasing importance of feeding high quantities of milk or milk replacer. So the old traditional, recommendation 2 litres twice a day in order to get them quickly on concentrates and so on.
This is so outdated and as farmers were shooting themselves in the foot and on several levels. So we now agree that we have to increase the amount of milk feeding for calves to make the rearing process more economic to have achieved better growth rates. But also have a higher quality calf at the end of this.
So there's increasing evidence and probably unchallenged evidence that increasing the milk feeding is beneficial economically in, in, on, on various levels. If then this increasing milk is obviously used as fed as whole milk, then that will then delay the uptake uptake of significant amounts of solid feed. And this can then also, predispose calves for, for, iron deficiency anaemia.
So it may be that with these recommendations, we, predispose our calves more towards this. Yeah. And M replaces.
They have around 100 milligrammes of iron per kilogramme powder. So they are fairly Fairly, well, well supplemented to it. So, anaemia is rarely an issue in milk replace of fat calves.
Yeah, but as soon as the calf is on startup pallets or any solid food, they normally meet the iron status there. OK, what effects are there of iron deficiency? So anaemia, as I say, both by reduced number and reduced lifespan of erythrocytes, that's the obvious one.
On the heart level, we do see reduced growth rates. We do find a higher prevalence of some diseases. and already in the mid 80s, or 40 years ago in East Germany, and I, I show this in a minute.
They have observed increased rates of diarrhoea and pneumonia in calves with iron deficiency anaemia. But we also found a reduced gut development. There is some suspicion it may also iron may also favour the Roman development.
But this is something, which is currently being sort of researched. Interestingly, in lambs, they found also a higher risk of upper nasal load. And this is Scandinavian work where there are lots of indoor lambs, similar situation as calves.
And they found that iron deficiency anaemia identified this as a risk factor for a nasal bloat in lambs. So if there is a flock problem, well that maybe is, is worth looking at the iron status if these lamps are, are red indoors. The immunity effects were researched in depth about 30 years ago.
So this was real calves, and I found that iron deficiency obviously led to lower growth rates, increased risk of pneumonia, increased risk of antimicrobial treatments. Decrease cell-mediated immunity, decreased number of neutrophils, so quite specific, on, on several pathways, yeah, unspecific and, specific immunity. And, and so on.
So that, on, on several levels, iron deficiency anaemia has affected the immune system. And this is his work again from East Germany, where they basically had a a calf rearing station where the calves were, arriving at about 3 weeks of age. And then they had 3 treatments.
I had no iron treatment or iron IM intramuscular. Or iron orally every day. And then they just looked at the cumulative, treatments for pneumonia and for diarrhoea, after the days on the holding, of, of these three treatments, and they found that the cart which did not receive any iron.
Had higher treatment rates for pneumonia, and they had higher treatment rates for diarrhoea. So the oral ones, daily fear at best, and the intramuscular ones, they got two injections, some, I think 2 or 3 weeks apart. They, they feared sort of in the middle.
So this is already 40 years old, done on farms in in East Germany then. So this effect was there, and they found that the reduction in disease. It was already present before the effect of the anaemia was corrected when they supplemented iron, so they already then speculated the direct effect on the immune system which is not just linked to haemoglobin and red blood cells.
So there's a direct immune stimulating effect of these iron supplementation there. So, can we give too much iron? What happens with iron toxicity?
I said iron is basically like an antioxidant as well, but too much of iron can, cause, Can also cause oxidative stress. So iron can be can cause oxidative stress if it's overdosed. I mentioned it may favouring pathogens.
There was a study with malaria patients. If they're anaemic from malaria, it's obvious to give some iron orally, but it has actually led to a higher death rates, because they said it may actually favour some, some other pathogens. And even viruses and parasites.
Seems to be favoured by, by higher iron status. So, this is where this scepticism comes from, if we over supplement iron. In animals iron toxicity has not been commonly described, so.
There, there were these things with children taking iron tablets, too many, yes, but in animals, it has to be severely overdosed to see any, any, any effects there. So, there's a therapeutic margin, and I talk about dosage, especially dosages and calves. That is actually not too much of an issue, and I talk about this in a minute in more detail.
So what are the risk factors for iron deficiency anaemia, which animals are at risk? So obviously, whole milk feeding and indoor housing with no access to soil. Yeah, we know that outdoor pig farmers are less inclined to inject their pigs with iron because if they can root in the soil, they will have contact with iron.
And, So, and then lack of solid feed as well. Yeah, so the more milk, the less solid feed, the more they are prone to iron deficiency anaemia. In cow cows and in pigs, it has been tried to feed the dams higher doses of iron, that had no effect or no significant effects on the iron status of the newborn.
So it's, it's an obvious thing to try to, increase iron status of the dam. But the effect on the newborn, was, was very, very little or non-existing. Yeah, I go through a couple of publications, the, the Ber one with the pneumonia and diarrhoea I mentioned already.
And, We did, some years ago, a study in lambs and goat kits, when, after finding out the iron issue in, in calves. And we looked, we sampled 20, kids or lambs, at 4 to 6 weeks of age. And in different settings.
So goats indoors, milk replacer, goats indoors and suckling, so they were all indoors, obviously, sheep, we had indoors milk replacer, indoor suckling, and outdoors and suckling. And looked at what was the main haemoglobin levels and what percentage of lambs or goat kits were under the reference range of 8 grammes per deciliter. And, it was obvious that, indoor goats suckling their dams or indoor red lambs suckling their dams were at quite a high risk to have low haemoglobin levels.
So it's a similar situation with pigs. And with calves, if they're indoors and on a whole milk, not milk replacer, that is a big risk factor there. Yeah.
So these are the, the mean levels. So goats indoors and suckling, sheep indoors suckling significantly lower haemoglobin levels, at, at one month of age. And we looked at the different ones, highly significant differences between these housing systems.
And this is just based on, 20 samples, but because the differences were so high, they were statistically significant. So if you have, problems with goat kids or with, with lambs indoor red, Do also think of iron deficiency anaemia there. And 5 years ago, we did this, larger study on calves.
So we looked at 237 calves from, 6 farms. They were all weight and blood sampled in the 1st 10 days of life were, tested for haemoglobin in total protein. And randomly assigned to either receive 1000 milligrammes of iron parenterally or intramuscularly as iron dextran or no treatment.
And, all calves were then wait again and blood sampled again at 6 weeks and then wait again at 12 weeks of age. Yeah. The daily life weight gains in hemoglobins were compared.
And we got the following results. So we had no reported adverse reactions. Yeah, we have no iron injection licence for calves in the UK.
So we needed to use an off-license product. So obviously, we had to report any adverse reactions. But, as I said, with these 100 plus calves injected and I've injected since another 250.
There were no adverse reactions, so, so from observed then. So that's, that's one of the outcomes. We found an increased daily life weight gain between weeks 1 and 6, which is an averaging about 78 grammes per day, and that was between treated and controlled calves.
So that was highly significant. That increase happened on all 6 farms, but because on individual farms, the sample sizes were low, so it was significant on one farm, but when we put them all together, the sample size was big enough and it was significant. And the haemoglobin levels, at 6 weeks were significantly higher in the iron injected calves, which again, is not surprisingly.
So while the, the controlled calves, haemoglobin levels decreased, by about 3.4 grammes per litre. The injected, sorry, the injected ones increased by 3.4, and the control ones dropped by, 12.1 grammes.
And calves with higher growth rates, were significantly more likely to show low haemoglobin levels at 6 weeks. So higher growth rates is a risk factor for, for iron deficiency anaemia simply because the uptake of iron is higher in faster growing calves. And when we talk about, you know, this is what nature intended, supplementing calves with iron.
Well, the natural growth rates in wild animals are much lower than obviously those in domestic animals, and we have good growth rates for a reason. And that's a similar effect in pigs, and in pigs, obviously, the effect is even stronger, but the pig doubles its birth weight within the first week of life. So they've got obviously compared to their actual weight higher, daily life weight gain, so even a higher demand for it.
So these were the individual results in the growth rate differences on those 6 farms. So, this is the number of calves on each farm. And this is a P value for each farm.
So let's say one farm was significant, the others were, non-significant. One had very little difference, but most of them had a, a reasonable difference. And as I say, altogether, it was highly significant, and the growth rate was, about, over 60 grammes per.
7 about 70 grammes per per day, so quite considerable difference in growth rates. Yeah. So, and then the haemoglobin levels I mentioned as well.
Yeah, this was consistent, consistently higher in, on all six farms. And, also, if you then look at the reference range of, of 90 grammes per litre of haemoglobin. Of the injected ones.
There were only 6 in total, which were. Which were under the level of the control ones they were 40, yeah, and the numbers were roughly equal. So, how much higher risk to be anaemic, obviously without the iron injection.
So what can we draw from that? The, improvement in growth rate and haemoglobin status is very consistent and significant. Faster growing calves are at higher risk of subclinical anaemia.
So if you've got maybe Holstein breeders who feed calves on whole milk, maybe look at those first. There's a high, on these farms, there was a high variation in daily life weight gain, between the farms. One had a problem with, pneumonia during that time as well in the calves.
So their main problem was definitely not iron deficiency. Their main problem were other things. So, and it's important to address those things as well.
Unfortunately, on these farms, the health data was quite scatty, so there's no, no health data whether, and this is a part of an ongoing study now to look at, at the, the health effects and treatment frequencies. But unfortunately we could not predict the effect of iron on the daily life weight gain by measuring haemoglobin levels. So it's not those which with the lowest haemoglobin levels at 6 weeks, which, which gave the biggest response to the iron.
So the, the size of the effect is, is very, very difficult to predict. So then we think about what, how can we actually measure the iron status. So, as a practitioner, how can we measure it?
It has been done in research facilities that we measure iron directly. But that has got for practitioners methodological difficulties. It varies during the day as well.
So then, these authors have postulated using serum ferritin as a more, more accurate way of measuring the iron status. However, ferritin is a species specific protein. And the human tests may not work for for calves.
So mostly we are still stuck with haemoglobin as a proxy for the iron status. And it's also obviously basis for legislation and for farm insurance schemes like RSPCA as well. Unfortunately, there are different, measures in the literature.
Some use millimoles, some use deciliters, per, sort of grammes per deciliter, some use grammes per litre. So the EU standards, say 4.5, the German standards and the RSPCA standards say say 6 around that region, and there is actually not a strong correlation between iron and haemoglobin.
So this is from calves. And, and the correlation is actually not, not very striking, but we still have haemoglobin as the main one we can use as a, as a proxy. And the question is then what is a good reference range?
So where should it be? And, you know, as I say, different authors, the bingo study, . They, they were about up here and this is a German survey of haemoglobin levels between 24 different farms.
These are farm averages. The light coloured ones are sucklers. The dark coloured ones are dairy herds.
And depending where you set the level, at the EU legal limit or at the spring of paper or at the German level or at the RSPCA level, yeah. You either have almost all calves being anaemic or you almost have none of the calves being anaemic. So, there is no fully agreed reference range, available at the moment.
So, see it, with a pinch of salt when, when, when you look at this. I think, these, sort of 6, which is about 9. 9 grammes per deciliter, it's probably a reasonable value to look at.
But see the levels in clinical context, and don't get too hung up about any, reference levels. So in the lamb study, the more significant effect was in twin lambs, and it was also known that In, calves that twins tend to show lower haemoglobin and hematocrit levels than singles. So, which is a bit surprising because we think twins get less milk.
They may eat concentrates sooner. But, in lambs and in calves, it has been shown that twins seem to be more, prone to iron deficiency anaemia. Health effects are controversially discussed.
Yeah, we've got the beneficial effect on the immune system and the haemoglobin, but we also know that, iron can feed pathogens. And there was a recent study, 4 years ago in Germany in Bavaria, where, which is purely epidemiological. So looking at risk factors, for neonatal calf, diarrhoea.
So they just looked at farms with the diarrhoea problem and farms with no calf diarrhoea problem. And look actually what are these farms doing differently? Yeah.
And then they put it into a model. Multivariate regression model and looked at management factors which make the calves more or less likely to get diarrhoea. And, what we expect is If they get 3 or more litres of colostrum, their odds ratio of getting, calf scour is 0.21, so they're only 1/5 as likely to get calf scour as if they, get, less colostrum.
Also, high level of milk feeding. So if you feed them ad-lib milk in the first week of life, Yeah, that gives them a much, much reduced risk of getting calf diarrhoea. So the feeding is not just feeding of milk volumes.
It's not just, good for, for achieving high growth rates. It seems to give them also a protective effect against neonatal calf scour. But then the surprising effect is when we looked at supplementation of iron after birth.
So, Odds rate you 10, so 10 times more likely to get calf diarrhoea if they supplement iron after birth. And with a high P value as well. Yeah.
So, here we are, you know, we've got the old Bringer study from 40 years ago, saying iron supplementation reduced the incidence of diarrhoea and pneumonia, massively. And here we have an epidemiological study showing iron supplementation after birth. Can be a risk factor for neonatal calf, scours.
So how do we get our head around this? So on this study, there was no information whether the iron was given orally or by injection. And from human studies, oral iron seems to be more potentially favouring pathogens and parenteral iron.
Also, it was not, it, yeah, so as I said, it was with . Or I yeah, I mentioned this, so, OK, and . So there is this concept of a nutritional immunity, but this study has also not postulated when actually the iron was given.
And there seems to be some evidence that if you give it very closely after birth, when the calf is still prone to get E. Coli scour, then feeding this can increase the risk. And in Germany, there are also oral iron supplementations.
Some of them can be given as a paste. Some of them can be. Added to the whole milk.
So they're called milk, whole milk enhancers. So they've got iron and other things in it. And they may be given on day one or two of the calf, and the calf is still susceptible to E.
Coli. So there's definitely a potential that is, This type of feeding does favour pathogens. After the pH in the upper masome or the pig's stomach is gone down to had lowered to a pH of 3, the calf of the pig is less likely to get E.
Coli scour. And in PIS, there's a recent study showing that, giving the iron at 4 to 6 days of age achieves the best growth rates and not at 23 or 4 days of age. So delaying this may actually counteract this.
Yeah. But in the end, we do need a large intervention study, on farms with accurate health records, to, to find this out. So there's definitely a question mark on this.
On the other hand, we're injecting millions of pigs with iron every week for the last many, many decades. But there's this concept that the low iron content in milk has got its, makes biological sense. Yeah.
And it's not, milk has not only got low iron, it also has got lactofein in it, in milk and colostrum, which is actually an iron binding protein. So not only is, is iron low in whole milk and in colostrum. But the mammary gland also excretes an binding protein which makes the iron even less available.
And lactoprine has been tried as a treatment for prevencaus diarrhoea, and that reduced mortality. So again, iron depletion. As a concept for for fighting bacteria.
And we know the same concept in the dry cow udder. We know that there's high doses of lactoferine. In the cow's udder at during the dry period.
Which is part of why the other in the mid dry period is so resistant against new infections and also eliminates any existing infections. So in practise, yeah, we are probably stuck with haemoglobin to diagnose, calf anaemia. There are some handheld test kits available as well, which are all sort of tried for humans.
Anybody who's given blood may have seen those. These are quite expensive, but they are cheaper ones available. And, So one I tested recently, has got a fairly good correlation with a reference lab.
So I would be happy to, to use this one for, for ongoing studies. They're much cheaper. You can do a haemoglobin for, 1 or 2 pounds or something instead of 10 pounds for, for other labs.
So, and also these, handheld kits could also be part of a blood transfusion kit where look on site. Whether an animal needs a blood transfusion, so that could be quite, quite useful there. So, Dosage, so sorry, prevention.
So 1000 milligrammes of iron, as a single injection, 3 to 10 days should be fairly safe. If you compare this with the dose in the piglet, yeah, the piglet gets about 200 milligrammes for 1.2 kilogrammes versus 1000 milligrammes for 40 kilogrammes.
Yeah. The piglet dose per kilogramme is about 6 times higher. So we've got quite a therapeutical margin in the calf.
Yeah. So iron levels in milk replacer obviously is an issue. They vary a lot, 20 milligrammes to 1500 to 150 milligrammes.
But we also have some recent research, the value of transition milk. So if you feed Colostrum or transition milk for 3 days or so, we found less mortality and we found less calf scour. And the question is, could this also be due to the delay in feeding iron supplemented milk powder, which may then favour pathogens.
So if we give colostrum for 1 day, and then on day two, we start milk replacer, highly supplemented with iron, could there be an issue with feeding E. Coli bacteria again? Yeah.
So where does this dosage dosage come of 1000 milligrammes? There's some old research, 25 years old, where they looked at, medication at different rates. So this is a control group.
There's a the haemoglobin goes basically down. And then they looked at 750,000 and 1500 milligrammes, and you see there's hardly any difference. There's a difference between 750 and 1000 milligrammes here.
But there's hardly any difference between the 1000 and 1500, so increasing the dosage by another 50%. Had hardly any beneficial effect on the haemoglobin levels, at, at sort of 4 to 6 weeks, after injection. So that's where the dosage of 1000 milligrammes comes from.
And, this is a safe dosage where licenced products, in other countries, normally use that one. So to summarise, the take home messages that a higher percentage of whole milk-fed calves appear to be subclinically anaemic. The effects are mainly on growth rates, the health effects are discussed controversial.
Diagnosing on a heart level is best done by testing haemoglobin at 4 to 6 weeks of age. We should be cautious about early oral iron supplementation, as this may also favour pathogens. Later supplementation and all supplementation by injection, has not yet shown any negative health effects, but further research is needed on this.
So 1000 milligrammes of parental iron, which is off licence in the UK, for example, as iron dextran, which is licenced for pigs, at 2 to 10 days of age, improves haemoglobin levels and growth rates very consistently. Similar effects have been shown, obviously at lower dosages. We went to 150 milligrammes per animal in, kids and and lambs as far as I remember.
And, But there's no known research on beef suckler calves. They obviously whole milk fat, but they're obviously outdoors. So we may have the lamb outdoor situation and not the lamb indoor situation there.
So, yes, if you come across any calf issues, and you are in a, in a whole milk fed situation, then iron deficiency anaemia should be part of the differentials. And haemoglobin levels at 4 to 6 weeks of age, could be a good starting point to, to to look further into this. OK.
Thank you very much. And, if you have any questions, please feel free to send me an email and, or if you have any suggestions, any other experiences so, I'm more than happy to discuss any, any issues and, or share any, any experience. Thank you very much.