This question came in by one of our trainers
"I visited a farm with a lot of problems with calf pneumonia. We started talking about how calves start creating antibodies. The farmer said the calves need bacterias to get resistent. I explained that it need colostrum for this. Now I was wondering, at what age do calves start with antibodies production in its immune system?"
Answer by Jan Hulsen & Joep Driessen
The calf starts with the production of antibodies immediately after it is born. Actually: it can already happen in the uterus, when the calf is exposed to pathogens there.
But the calf has to start from zero and has no specific antibody production infrastructure against any bacteria or virus or archean or protozoa etc. Nothing at all.
It takes at least (…) around 21 days to produce a substantial amount of antibodies. Which means that a calf has the first substantial protective immunity from it’s own immune system starting in it’s fourth week of life.
It is assumed that white blood cells from the dam, the mother, that the calf takes in via -fresh and untreated- colostrum, support the calf’s immune system in maturation and in functional development.
So looking at it from a bit of a distance, the whole plan is that the calf is gradually exposed to a low number of microbes against which it needs to develop specific immunity. The more this process is spread out over the first months of life, which is also what colostrum does, the better.
Cellular immunity is functional from day 1. This is an explanation for the fact that vaccination on mucosal membranes is functional from day 1, like nose spraying.
Antibodies from colostrum “catch” many pathogens and thus reduce the exposure of the calf’s immune system, even to such an extend that it take a longer period for the calf to develop it’s own complete set of specific immunity.
Which is very functional, because without protective immunity from colostrum, the calf will just simple get an overload of micro-organisms against which it has to develop immunity. It is not just pathogens that the calf needs to develop immunity against, there are hundreds of microbes that it will be carrying on the skin, in the intestines, in the airways, etc. For all these microbes, the calf needs to develop a handling system.
Plus the whole system of control of the immune system needs to be matured and set. All immune reactions are highly balanced, as over-reaction can be just as harmful or even more harmful as the infection itself.
Immune reactions require an enormous amount of energy. On low feeding regimes, low energy and protein intake, calves are less capable of handling massive immunity challenges.
So looking at it from a bit of a distance, the whole plan is that the calf is gradually exposed to a low number of microbes against which it needs to develop specific immunity. The more this process is spread out over the first months of life, which is also what colostrum does, the better. And the less pathogenic microbes the calf is exposed to, the better.
I think the impact of poor hygiene is often under-estimated in practice.
When hygiene is a big issue, focus on improving this. There is certainly a limit to the protection colostrum can provide and to what the calf’s own immune system can handle. I think the impact of poor hygiene is often under-estimated in practice.
Very often the cell count of colostrum will be high on farms with poor hygiene, which will also reduce the immunity of the calf. In more simple words: the materials used for collection and handling colostrum will more likely be contaminated, which will lead to high amounts of microbes and potentially pathogens in the colostrum already. Calves absorb far less antibodies from contaminated colostrum, than they do from “clean” colostrum. Field studies show that around 30% of colostrum fed has a too high bacterial contamination.
Sick and weak calves will also eat little calf starter and have poorer intestinal resorption, so put extra attention to good intake of vitamins, minerals and trace-elements. Immune reactions need specific types of vitamins (E, A, C) and minerals (i.e. Cu, Zn).
How much colostrum do you feed?
We can't emphasize enough the importance of - clean - colostrum. Who feeds all first colostrum (6-8 liters) to the cald in the first two feedings? How many days do you hive colostrum/milk from the own mother before you go to powder milk?
Please share your thoughts below.