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Re: [RC] SCID : Calling vets and breeders breeding decisions - heidi1. Have your animals tested for any bad recessives that may be present in the breed. This is easier said than done, since SCID is the only lethal recessive in the breed for which there is a test, although there are several other lethals present in the breed. And unfortunately, simply culling the carriers immediately without any other consideration increases the carrier rate of the lethals for which one cannot test. Additionally, simply throwing horses out for being carriers does not induce people to WANT to develop tests for the other lethals, for fear their own horses will be subject to similar measures. If your animals are clear, breath a sigh of relief. Indeed, it is always easier if they are clear! :-) 3. If your mare is positive for a bad recessive, look at her very very carefully. Get the advice of respected breeders. Very few of us have mares that are so special that the breed would suffer if they never reproduced. They may be special to you, but are they genetically unique and a super horse? This is good advice with regard to breeding ANY mare. That said--there ARE no perfect horses, so one has to weigh all faults, rather than making breeding decisions solely based upon one fault. 4. If your stallion is positive, and genetically extremely unique, and a really super stallion you have a problem. First, only breed him to negative mares. Well, actually, we HAD a problem. Past tense. Now that there is a test, the problem is miniscule compared to the guessing game that used to go on. Make sure that the mares he is bred to are owned by knowlegable people who will be looking to breed the defect from the breed. This is also important, regardless of the faults with which one is dealing. This shouldn't be a consideration just for breeding carriers, IMO! They should be willing and able to cull the positive horses from the breeding program. That is keeping only negative animals to breed on. I would be very supprised if a truely exceptional stallion bred to exceptional mares did not produce at least one exceptional colt that was negative before he ended his breeding life. This is indeed the goal, but it is not always realistic to accomplish it in one generation. Many of us do not breed our stallions to every "empty uterus" that comes along, and we only want to keep sons who typify what it is we are trying to do. Hence we don't always have all that many sons from which to choose, SCID or no SCID. If I get five colts by a carrier stallion, and only one is a carrier, but he is head and shoulders the best quality of the five, which one am I going to keep intact? You bet your booties that I'm not going to throw the baby out with the bathwater by keeping an inferior colt just because he is clear. All else being equal, then YES, I'll choose the clear colt! Since Wendy and I do not have 50 years, and lots of money we have decided to only breed negative mares to negative stallions and let others work at preserving the few exceptional blood lines that happen to be positive. One does have to make one's own decisions in this regard, and while I prefer to think of being part of a continuum with regard to decreasing the SCID carrier rate over time while maintaining the rest of the genetic material represented in current carriers, rather than being the "lone ranger," I nonetheless respect your common sense attitude, Ed, in understanding that this IS your personal choice, and not condemning those who choose to work wisely around the gene by testing, even if it means continuing to test into subsequent generations in some cases. Heidi =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Ridecamp is a service of Endurance Net, http://www.endurance.net. Information, Policy, Disclaimer: http://www.endurance.net/Ridecamp Subscribe/Unsubscribe http://www.endurance.net/ridecamp/logon.asp Ride Long and Ride Safe!! =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
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