Here's another article on cryptorchids: http://www.thehorse.com/ViewArticle.aspx?ID=1514&kw=cryptorchid
A quote from the above article, originally published July 01 2004 as Article # 1514: >> This genetic defect is not as harmful to the horse as some other inherited faults, since the affected animal can live and function normally (but he might have aggressive behavior that could put handlers at risk). "We castrate a high percent of these animals, and as long as horse owners don't mind the added expense to geld the progeny of a cryptorchid stallion, cryptorchidism may be an acceptable inconvenience if the horse has other qualities that are desired," says Yarbrough. "It's a matter of whether the horse owner wants to put up with the inconvenience, and whether we want to take on a bigger financial burden when gelding the offspring." << This is key to me - shouldn't we be concerned about a condition that can require expensive surgery (possibly as much as $2000 compared to maybe $200-300)? It appears that some colt's testicles fully descend as late 2-3 years...but if you wait that long to geld, you have to assume the colt is fertile in the interim, and manage him as a stallion. Waiting may bring the cost down (maybe not) but it adds other concerns. On the other hand, if I, as a breeder have a young colt that is a cryptorchid, I don't feel good about selling him until he is gelded. Will I ever recover the extra cost of the more complicated surgery? No way. In Iceland, though, there are other ways to dispose of colts, ways I find unacceptable. Many (most?) cryptorchids make fine geldings, albeit expensive ones, if gelded completely. Here's another quote from the above article: >> Cryptorchidism in horses is thought to be inherited, although the actual mechanism of inheritance is not yet fully understood. Ahmed Tibary, DVM, PhD, associate professor of theriogenology at the Veterinary Teaching Hospital at Washington State University says, "It has been confirmed in sheep and swine to be hereditary, and we assume it is in horses. Some authors think it's inherited as a dominant autosome (in a pair of chromosomes), and others think it's a recessive gene (that must be inherited from both parents to show up in the offspring). In my experience, I've seen a lot of cryptorchids in Akhal-Teke horses, a breed with a limited gene pool." Within all breeds, there are some bloodlines that produce a greater number of cryptorchids than the average for that breed, and some breeds have a higher incidence. A study that looked at more than 5,000 cryptorchid horses (documenting breed incidence, among other things) found the highest number in Percherons, Quarter Horses, Saddlebreds, and ponies, says Tibary. "From that study, it was also surmised that the breeds that don't have many cryptorchids are the ones that have tried to eliminate this trait by not allowing them to be used for breeding," he adds. "This lends credence to the idea that it's inherited, but at this point we're just using the experiments from other species to assume it is hereditary in horses," he says. << That last paragraph is key to me: maybe cryptorchidism is so common in Icelandics because it's always been ignored. In Iceland, a cryptorchid colt whose testicles never fully descended could easily be slaughtered and eaten, but that's not acceptable in the USA. Nor would I recommend it, since I know several cryptorchid geldings who went on to make wonderful riding horses after they were gelded. We need to stop thinking of the condition as normal - common does not equal normal to my way of thinking. I think it's time we acknowledge this as a problem within our breed. We're not in Kansas - or Iceland - any more, so we need a better plan than we have. Karen Thomas, NC No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.463 / Virus Database: 269.5.9/773 - Release Date: 4/22/2007 8:18 PM
