The last trimester, fescue, selenium...
MANAGEMENT TOPICS OF THE SEASON FOR THE BROODMARE
Care of the Broodmare in the Last Trimester
After the rush and fanfare of breeding the mare in the spring, she leads a relatively quiet life the rest of the year. Other than the all important rhinopneumonitis (rhino) vaccination at 5, 7, and 9 months of pregnancy and the boosters for the diseases we discussed last week, she is often left pretty much alone. The time all of this changes is now, late winter and early spring. Just after the mare’s 9th month rhino vaccination her life becomes much more involved.
No later than the end of the 9th month of pregnancy the mares should be removed from any fescue grass or hay. Unless you are lucky enough to have a pasture free of fescue, and we would all like to see that pasture, the mares will need to be supplemented with a non-fescue grass hay or hay consisting of all or part alfalfa. Remember, if you are providing all the roughage, an amount equal to 2% of the mare’s body weight is the minimum amount to meet her needs. If she needs to gain weight, a grain supplement will speed that process. Even if the mare is in adequate condition or, heaven forbid, overweight, she should still be fed four pounds of grain each day during the last six weeks of pregnancy to provide extra energy and protein for the rapidly growing baby.
Six weeks before the projected due date the mare should receive an injection of selenium and vitamin E. This will improve the health of the udder and uterus. The medication will help neutralize the effects of the fescue endophyte. The most common effect of infected fescue on the brood mare is agalictia, or “no milk.” At foaling there will be only a flat udder and no colostrum or milk.
Even more discreet but just as serious is the effect of fescue on the foal’s own immunity. If the mare is without milk because of fescue exposure, the foal will also have problems with its immune system. This becomes very important when the bay is confronted with the challenges of its less then sterile surrounding. The stressed baby is the one that will develop a septicemia or generalized infection. The baby born without colostrum and milk is certainly stressed. The baby is very likely to develop a systemic infection which may show itself as a swollen joint or a very high fever. Without treatment the foal may even die. Enough of this depressing conversation, but it does emphasize the importance of limiting the mare’s exposure to fescue.
The other signs of fescue exposure are a tough placenta that is difficult for the foal to escape from at birth. Along with the tough placenta we usually see a “dumb” foal. This can be the major heartbreak of raising foals. The baby will almost do the things expected of a normal foal. It will almost stand but usually will not. It acts like it would like to nurse but never quite learns how. This activity continues until it has worn you out, and then it dies anyway.
So a few precautions are well worth the effort. In addition to the above treatments and ration changes, we can watch for udder formation as the foaling date approaches. If this is the mare’s first time to foal, she should start having some progressive activity a month in advance. This may at first be only a thickening of the tissue supporting the teats, but does indicate some increased blood flow. With this start, the udder should continue to develop. This much lead time is important because the udder must develop milk producing tissue as well as start filling with colostrum.
If the mare is a veteran of past foalings, her udder should start filling two weeks before the foaling date. We can allow her a little more time because her udder only needs to fill. If either mare does not meet these deadlines, we should be contacted. There are additional medications which will help the udder develop at the last minute. It only takes one experience with a foal on a milk substitute and with a compromised immune system to realize the importance of what we have been discussing.
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