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Re: [RC] Genetic diseases - heidi1. Does the individual have a unique enough genetic heritage to warrant breeding on? When we (actually Wendy) started looking for stallions for her SCID clear mare, we quickly found that there was a large pool of suitable stallions, with pedigrees that suited Wendy and complemented the mare who were SCID clear. This may well be the case when you are looking at just one cross to produce one foal for your own use. It is frequently NOT the case when one is looking at a long-term breeding program that spans over several decades and many generations. Is this colt's heritage unique enough that the genes must be preserved? When I look at the pedigrees of a fair number of stallions (particularly in color breeds) I can not see any plan in the breeding program. It looks like horses (who may have been good individuals) were just bred together. And this IS all too often the case--in which case the horse (whether it be a mare or a stallion) is not really bred to be a breeding animal in the first place. So yes, in such cases, gelding should be the first consideration, even BEFORE one tests for SCID. A great majority of American Arabian pedigrees represent a very random set of breedings, so what you say holds true in such cases--not to mention that there are a thousand more just like them down the block. I then begin to believe that there is a good chance that even very superior individuals will produce a variety of offspring, many of whom will not resemble their sire (or dam). True, to some extent. The more variation in the pedigree, the more variation among the offspring. The more consistent the pedigree, the more consistent the offspring. That said, a pedigree is not a blueprint--it is a set of possibilities. There is always going to be SOME variation, depending on how much variation there is in the pedigree. Is this colt's performance potential that outstanding that he must breed on? (i.e. does he have the potential of producing world cup winners?) But more importantly (and again, why are we just harping on the colts here? The mares are the REAL crux of any breeding program...) even if this colt HAS great performance potential himself, is he bred in such a way that he is APT to pass it on? See the comments above about variation in pedigree. I learned an early lesson in this with Thoroughbreds--we had ranch mares sired by a Remount stallion who was a complete dud at the track, but was sired by a stallion who won both the Preakness and the Belmont and was second in the Derby. This stallion (the sire) came from a very unproductive pedigree, and was the one fluke in his family--and true to his pedigree, was unable to pass on his capabilities. Performance isn't the only key to breeding--the ability to pass it on has to be there as well. Is this colt's conformation extremely good? Bingo. SCID carrier status is just one fault among many. When you get the colt who has exactly what you want to carry forward from that breeding, and he is head and shoulders above his brothers in quality (or the filly, I will add again), but he/she is the one that happens to be the carrier, you are far better off to go with the quality individual and manage the carrier status--you will have another shot at weeding it out in subsequent generations. I would bet that in almost all cases, given the numbers of Arabian (or QH when genetic testing becomes available) horses in the US, if one were objective, this colt would not be in say the top 10% in all these categories and thus should be gelded. To be fair one would do the same evaluation of a filly, and choose not to breed her on the same basis. Thank you for including the fillies. As it happens the QH problem with HC happens to be in a very prolific line. Many of the Arab SCID carriers are from families that were so depleted by politics and fear of SCID that they have become rare birds indeed. Some of these families are slowly being built back by diligent breeders who take care to work around SCID--but a great deal of genetic material has sadly already been lost to the breed. And in many cases, it represented some of the best the breed had to offer. There are also some "preservation breeders" of relatively rare lines Arabian horses. Their breeding programs need to be much closer to the breeding of rare breeds of horses. Bingo. See the above. The reason for being a "preservation breeder" is not to preserve names in pedigrees--it is to preserve the traits that the ancestral horses had, which are in too many cases rare. It is no surprise to look at the stats of Tevis winners and see how the "preservation" lines appear with a far greater frequency than what they appear in the general gene pool. Preservation breeding within the Arabian breed is about keeping the sorts of Arabians in production that people can get on and ride, and do athletic endeavors. And not just rare breeds--as above, this applies within breeds as well. I know of (and own one, among my 13 stallions) carrier stallions that are the last representatives of entire branches of their sire lines. Will we breed them? You betcha. Do we hope we get a clear son or grandson at some point that carries forward their other qualities? You betcha. But to geld them would be idiotic. They will,of course, look for clear offspring as preferred sires and dams of the next generation. I have read a bit about the breeding practices of early Arabian breeders in the USA. The stories of these programs, with their intensive close breeding of the few outstanding individuals, are very instructive as to how to properly run a breeding program. If I remember correctly, Bazy once imported a stallion that was rumored to have produced what is now known as an SCID foal. She advertised nationally and bred him to about 20 mares who had produced SCID foals. She got almost half SCID foals. She immediately gelded him because she did not want to breed this fault on in her herd. Note that this was all done before the advent of testing. If this were to happen today, I'll bet that she would have bred him on, and tested his offspring, removing the positives and breeding on only his get who were clear. In her case she could breed multiple times to the right mares and then only select the absolute best to remain in her program. How many of us have the money and time to do that? Well said. Most of us don't have the money, but we are taking the time... Heidi ============================================================ REAL endurance is eating egg salad sandwiches for 3 days straight! ~ Heidi Sowards ridecamp.net information: http://www.endurance.net/ridecamp/ ============================================================
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