Beef Man":oj5kkmrn said:
I've got a question. One of my grandsons has some pretty decent yearling heifers and wants to AI a few to club calf and try to market them as show steers.He is 13 years old and this is his own idea. I was quite impressed with his plan and thought it whould give him a nice boost on his way to maybe learn something different and on his own. But I surely would like to know more about these genetic problems and could he use the heifers anyway in a future breeding program??What is TH orTpha?? I as a 14 year old learned all about dwarfism in a old hard knocks school and it wiped me out of the breeding cattle business in 1 year. Tough lesson learned and remember it well. So thought I could ask a question and get a headstart on some problems before a wreck happen's. Thank You--
My fifty cent crash course. Maybe oversimplified, but it covers most of what you need to know.
TH results in malformation of the hind legs - can be slight or extreme. TH affected calves also often are born with hernias, and/or a hole in the top of their head. Affected calves are usually stillborn. It traces back to a particular line of imported Shorthorns. Before that, though it can't be directly traced to there, the only known recorded incidents of what seems to be the same thing occurred in the Galloway breed. It's a simply inherited genetic defect - statistically, mating 2 carriers will result in 50% carriers, 25% clean and 25% affected offspring. Mating 1 carrier with 1 clean parent will result in 50% carrier and 50% clean offspring.
PHA is where the fetus' lungs don't develop properly. It results in the calf taking on fluid, and if they're carried full term, it can result in huge, deformed calves (always stillborn) that often have to come out in pieces or by C-section. It can result in a cow not surviving, and often the ones that do won't breed back. Inheritance is the same as with TH. It's origins are kind of fuzzy - it can be traced back to a few old Maine Anjou lines, but there seems to be a dead end in connecting them to each other and an original source.
TH is a deletion in the gene sequence that's involved in forming the hind leg, and seems to be associated with big bone, straight legs, and maybe lots of hair. Thus, it's been hard to get away from in the club calf deal.
TH and PHA carrier status is available on most AI sires - if you don't see it, ask. There are many good, clean bulls available.
I may sound like carrier's just don't matter to me, but really, that's not the case. I do have a few carrier females, bred back before we knew about these defects. They're too valuable to throw away, but I mate them clean. Always. I won't own a carrier bull. I do breed a few known clean cows to carrier bulls AI. All the bull calves get cut, most females get sent to a feedlot. If we want to keep one, we test her, and breed accordingly. We have not had an affected calf with either TH or PHA since we knew what they were and only 2 before that.
My advice for someone just starting out would be to keep it clean. Lot's of people are going to tell you you'll never raise a great one that way, but you can raise some good ones, and sleep better at night.