As I have said before, I dont think there is any reason to not allow carriers to register, I dont think there is anything wrong with having a carrier in your herd. I think the best thing that breed associations can do is require potential carriers to be tested in order to register, and many of them that have problems with genetic defects either already do this or are in the process of implementing it. I would agree that any animal that is Homozygous for a potentially lethal genetic defect should be banned from registration(just my opinion), but since TH/PHA are always lethal when homozygous we dont have to worry about that. I think the biggest thing here is responsibility. I would disagree with those that say no breeder is knowingly breeding a carrier to a carrier, not only do I believe that there are those out there willing to take that risk, I think we would be foolish to believe that some of them are not doing it. But I would say the majority of lethal calves are theresult of breedersnot being educated or iiresponsible. I think any responsible breeder who knew they had a potential carrier should either have that animal tested prior to breeding them or just assume they are carriers and just breed them to a clean animal. Or how many new breeders know that their heifer is a carrier and that the bull they want to use is a carrier, but never take the time to learn what that means so they go ahead and breed anyway? I think its a matter of being responsible and what risks your willing to take. Personally I am not in a position to be able to afford to risk that dead calf, but I want the best odds at a greatcalf, so I am going to spend the money to test a heifer before breeding her, that way I can make an informed decision.
Also like many others have said, we are never going to erradicate potentially genetic birth defects. They are gene mutations that can occur at any time. So even if we erradicate them either the mutation can occur again or a new one can pop up to replace it at any point. I dont think the focus should be so much on erradicating every potentially lethal mutation that shows up, but we should be focused on learning about and educating others how to properly manage them as to prove the risk.
And while I completely uderstand the point of view, my opinion is I am not convinced that TH/PHA status directly affects quality. I am not blind or stupid, I know that the vast majority of the "great ones" going in the show ring are either carriers or are out of carriers. And I fully admit that it is completely possible that someday a geneticist my find a direct genetic link between that mutated genes and the genes that affect the postive traits such as hair, muschle and bone. I am just not totally convinced that that will happen yet, I see the potential for it to, just not yet convinced that it will because I also see the potential for it going the other way, just like it did with HYPP in QH's and stress in pigs. Many of the top breeders in those industries believer the same way about those issues as many of us are viewing TH/PHA now. And while I think its a little far fetched to say that they have since had success breeding HYPP negative horses or stress negative pigs, that were BETTER than the carriers and postives, I dont think it is at all far fetched that they have had success breeding negatives that are every bit as good as the positives. True most of them have carriers in their gene pool somewhere, but doesnt change the fact that they themselves are just as good and negative. I still see potential for this happeing in the case of Th/PHA, and again I freely admit that I may be proven wrong someday, heck it may even be tommorow that a geneticist announces that he discovered that link, but it hasnt happened yet.
But most of all this MY opinion, I am not trying to shove it on anyone or berate anyone for their point of view, because I can understand the point that all sides make.
