Seasonal reminders, colic, rhino, etc.
SEASONAL REMINDERS WE HAVE OVERLOOKED
This week we will discuss topics we discussed in the last few months. However, from just this week’s cases, apparently not everyone dropped whatever they were doing and read this column! Drawing from the cases presented to us this week for ideas, we will discuss rhinopneumonitis vaccination, water consumption, roughage in the ration, and preparation for breeding. Actually we did reproductive examinations on several mares this week, so the mare owners are doing the right thing. I just enjoy talking about this part of horse practice!
Many of our mares are in the latter stages of pregnancy. This is the time we begin to see abortions due to the rhinopneumonitis virus interfering with pregnancy. The “rhino” vaccinations need to be given on the fifth, seventh, and ninth months of pregnancy. The abortions due to this virus are usually between the eight and tenth month. The vaccine does not stimulate a strong immunity due to the structure of the virus. With repeated vaccinations, immunity is increased. So, by the time the third injection is given, the mare is pretty well protected. If the vaccination is neglected or forgotten, the last trimester of pregnancy is when we see the abortions, and we are seeing them now. The mare will usually abort with little fanfare. The fetus has been killed by the virus and once the mare recognizes this, she will reject it. During the time this recognition takes place, the placenta usually has separated from the uterus. Therefore, the fetus and placenta can be passed and the mare will show few problems. In fact, it is easy to miss the event all together, and only later will you notice the mare is not as full looking as she was. Examination will find her open.
This is probably more than you ever wanted to know about this disease. If the vaccinations are given on the 5th, 7th, and 9th months of pregnancy, you will not have to worry, as they do a good job of protecting the mare.
With the recent week of cold temperatures we saw more than enough cases of impaction colic. The water became very cold and the horses reduced their consumption. This reduces the moisture and bulk of the stool, reduces the mucous in the bowel lining which acts as lubrication and, as the stomach contents pull water from the circulating blood supply, dehydrates the horse. As the stool becomes dryer, its movement slows to a crawl. Normal intestinal gas and the other foodstuffs backed up behind it, causing the intestine to swell. This results in discomfort to the horse. The signs are discrete at first, as the horse only feels as bad as I do after Sunday dinner at my mother’s. It may lay down and stretch a little, and may be a little restless as it tries to find a comfortable position. As the buildup continues it will try to roll. Of course this is the time it gets in trouble. If the discomfort is not relieved, rolling becomes more frequent until a loop of heavy bowel flips over the others, strangulating the bowel (sometimes called "twisted gut").
Treatment should start as soon as the early signs of discomfort are recognized. If lubricants, fluids (both IV and oral), and pain relievers are administered quickly, the impaction can be loosened and movement can be resumed. This gives the patient tremendous relief.
To prevent a repeat of the same problem, salt should be added to the feed, in addition to the salt already available free choice. This will stimulate additional water intake, even if the water is cold. Keeping the horse hydrated during the winter is important in preventing impactions from occurring.
We look forward to continuing this discussion next week. If you have any questions you would like to see discussed please call them into our office.
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