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Twin foals bad?

From: Angie

Dear Jessica, I know that it is not really breeding season any more but I am thinking ahead to next spring and I have a question that has puzzled me for some time. In March of this year, we bred our three mares and all of them "took". Our new veterinarian (we moved to a new state last year) verified the pregnancies with ultrasound, which is what our old vet always did too. But the new vet wanted to come out to the farm again and check one of the mares later, because he said she showed that she had twin embryos. We didn't do this because my husband says that twins are very unusual and if they do happen you just get "two for the price of one", and that the vet just wanted the money for another visit! Since that mare is apparently not even pregnant any more, I am wondering if my husband is right and maybe we ought to be looking for a new vet? Wouldn't it be hard to make such a mistake -- saying that a mare was carrying TWO embryos when she didn't even have ONE? (The other mares are pregnant).

Breeding horses is new to me and sort of new to my husband, who was brought up on a cattle farm, but horses aren't exactly the same. You are probably wondering what my question really is, and I guess it is two questions, first "What do you think this vet was thinking?" and then "What is wrong with having twins anyway?" It is important because we will probably breed the mares again in the spring.

Thank you so much, this is an incredible service.


Hi Angie! Let me begin by saying that the very best way to find out what a vet, or anyone else, is thinking is to ASK, either at the time "What are you thinking?" or later "When you wanted to check that mare again, what were you thinking?" ;-) You won't offend a good vet by asking questions, and a good vet is the only kind of vet you want!

I can make some educated guesses, though, and share them with you -- and give you some information about horse-breeding in general and twins in particular. That will give you some ideas to consider, and to keep in mind when you talk to your vet, and to discuss WITH your vet.

First, NO, I don't think he was just trying to make more money. I think he was doing the right thing -- if one of your mares had twin embryos, the vet would need to monitor her and help get rid of one of them if the mare didn't manage it on her own. The ideal situation would be a mare with ONE embryo, bringing ONE foal to term.

There are good reasons for this. It's difficult for a mare to bring twins to term, terribly hard on her to deliver them, and then the poor breeder has two not-very-useful new horses. Twins are almost always smaller, weaker, less well-developed, and sometimes have bent or twisted limbs. There's just not enough room in the uterus for full development and free movement of more than one foal. Many mares abort when they are carrying twins, but often at five months or later, which is bad for their health AND bad for their owners' breeding program, as it effectively ruins their chances of being bred that year. For the breeders, it's heartbreaking to discover these abortions, expensive to deal with an infected, stressed mare, and -- if nobody notices at the time -- disappointing to realize many months later that the mare hasn't been pregnant in some time.

Some mares have a tendency to twin, and these mares need to be monitored carefully by the veterinarian. Some breeders won't even breed mares that seem to twin regularly -- they feel that it's an ethical matter: that breeding a mare with a tendency to twin (and who may pass it on to her offspring) is like breeding a mare with any other nasty heritable defect, and that unless there is some truly compelling reason for breeding from THIS mare, they can let her go.

You probably don't need to go to this extreme, but it's a good idea to have the veterinarian monitor any pregnancy just on principle. Current research indicates that many mares do carry twin embryos during the first few weeks of pregnancy, but that the second one is frequently resorbed early, even without a veterinarian's intervention -- "Mother Nature"'s way of eliminating the problem. We only know about this now because so many mares are checked soon after conception and again at a few weeks -- if the mares were checked only after several weeks and found to have a single embryo in situ, it might simply appear that there had been ONE conceptus from the very beginning. If the mare does NOT resorb the second conceptus in those first few weeks, she may abort them both during the next few months, while the embryos are so tiny that you literally wouldn't notice them even if you knew where they were in the stall or field.

So, you see, twins are not "two for the price of one", but rather "two problems for the price of one foal", and the mare's health can be compromised as well.

By the way, one warning: DO talk to your vet about how to handle the births of all your foals, and do some reading on your own. I highly recommend the books "Blessed are the Broodmares" and "Blessed are the Foals", both by veterinarian M. Phyllis Lose. And be sure that your husband participates in all of this. Mares and cows are quite different, and a cow may have a calf "stuck" midway in the birthing process, half in and half out of the cow, for HOURS, and the result can still be a healthy cow and calf. Horses are different -- foaling is a fast, explosive process, and a "stuck" foal, if not helped, will soon be a dead foal. The key difference is that a "stuck" calf is still receiving oxygen through the placenta, whereas a foal is not, and will need to proceed through the birth canal and make it into the outside world and then BREATHE so that it can live. The result of a "stuck" foal is likely to be a dead foal and possibly a dead mare, so before your mares are due to foal, you need to make yourselves aware of the stages of labour, of the signs of trouble, and of the timeframe for a safe birth. Talk to your vet about all of this, and talk to him about what you can and cannot do to help the mare in such a case -- again, what would be appropriate with a cow and calf can be deadly with a mare and foal.

Most mares seem to manage the foaling process nicely, so don't worry too much. But DO be prepared, and don't hesitate to call your vet and have him come out and show you how to prepare a safe foaling stall, how to handle the mare, how to handle the foal, what items to have on hand, and how to reach him (and, if possible, one or two alternate vets, in case yours is unavailable) if there are any problems.

Good luck with the new foals!


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