A recent comment that lodged in my mind was the increasing evidence that colostrum ingestion in the first few days sets lifetime productivity. There is some Massey University data that has linked colostrum intake of triplet-born lambs to survival rates. And there is also data that links the amount of colostrum produced to ewe condition score at lambing.
It is a huge difference and probably one of the factors that results in better condition ewes having higher lamb survival. Are there other ways that can enhance colostrum production? Is it the mechanism by which lambing on some herbs can deliver higher lamb survival?
Another discussion in this forum was the long-term effect of early calf growth. For example, calves that have been grown faster before weaning – regardless of their subsequent growth rate – have higher milk production, and to a lesser extent, an earlier age of puberty. Also being examined is the nature of that feed being supplied before weaning.
There is some evidence that more milk is better. This is not just for better growth rates but for better subsequent performance, like the colostrum effect. This flies in the face of the minimal milk allocation to rearing calves that is now so common. While we know that weaning lambs very early to very high quality feeds can work in terms of their health and growth, are there other factors that come into play that could have a negative impact?
There are probably many production outcomes measured that are influenced by seemingly unrelated factors. The colostrum story above is one such example. The whole world of epigenetics is another, although the colostrum outcome could be an epigenetic one. This phenomenon could turn our understanding of drivers of production on its head.
Epigenetics is “the study of changes in organisms caused by modifi cation of gene expression rather than alteration of the genetic code itself”. So in our livestock systems it is when the environment influences how the genetic package behaves. Again from Massey work, underfeeding ewes at a certain stage of pregnancy can infl uence some aspects of performance of that ewe’s granddaughters.
This is an epigenetic effect. In sheep and humans there is an effect of the dam age on health or production outcomes. I presume that this could be an epigenetic effect. As we learn more, manipulating the power of epigenetics could create big opportunities. Of course, there are diseases that arise from distant influences which do not come under the banner of epigenetics.
Enzootic pneumonia is a good example. We all know that dust, heat, and mouth breathing in lambs are triggers for pneumonia outbreaks. But factors much earlier in the lamb’s life load the pneumonia gun. It could be aspects of their time when suckling or at weaning.
However, it is a two-factor (or more) disease, much the same as with bearings in ewes. Something must set up the susceptibility of the ewe before she gets to late pregnancy. Survey work would suggest that one of those factors is the change of body condition score in the first third or half of pregnancy. Probably what’s not as clear is what the triggers are in those three weeks before lambing.
I recently explained to some farmers who were celebrating a low bearing year that their result was because of the spring alignment of Jupiter and Mars. I could not keep the grin off my face long enough to give that explanation any credibility.
Another fascinating bit of information that came out of this dairy heifer forum was a report on the productive outcomes of weaned calves driven by the pattern of growth.
The real bit that caught my eye was the superior lactation performance and better feed conversion in heifers that had periods of compensatory growth in reaching their weight targets. That is, heifers having periods of forced lower feed intakes, followed by periods of ad-lib intake right up to calving, consumed less feed in reaching those targets and produced a lot more milk in their first and second lactations.
The degree of underfeeding was not extreme at all, certainly nothing similar to what R2 Friesian bulls can be subjected to in winter. I wonder how much of this can be applied to beef heifers, and possibly even hoggets, because the prize could be higher performance by feeding in a particular way that requires less feed.
Dairy herd management may have the potential to teach us much.
