Genetic defects are not a new subject, and there have been hundreds of commentaries out there discussing it. Now it's my turn to talk.
Since our cattle operation is concentrated mainly around Maine Anjou and Chianina genetics, we have great exposure to the risks of the genetic defects PHA and TH within our herd. ZNT Cattle has made a conscious effort to not have carrier cows in our herd, and to not breed to carrier bulls. That being said, we are not immune to the fact that these defects are out there, and some cattle may be mis-represented, either by mistake or on purpose, as to be free of defects. Thank goodness for testing!
There is a bigger issue to this than just having 1 or 2 show heifers that need to be tested to see if they are carriers or not. Just because some of these carrier cattle go on to be shown, and enter into registered herds where they can be tested and bred accordingly, doesn't mean this is where all the carrier cattle go. Hundreds, or even thousands of these "reject" cattle are making it into the commercial herds every year, either through the sale barn, or maybe through a neighbor selling to a neighbor. The typical commercial man does not have the time to keep track of every genetic defect out there, nor do they have the money to test their entire herd for every defect that comes along. And they should NOT have to!
It is the moral responsibility of seedstock producer and multiplier herd to reduce, or even better, eliminate genetic defects from their breed. I understand that it may not be financially feasible to just eliminate these cattle from their herd, but they do have the choice to make a conscious effort to reduce the amount of carrier cattle their herd produces.
Simple Genetic Lesson: Same applies to TH
PHA Free Bull x PHA Free Cow =
100% PHA Free Calves (Normal calf with no recessive genetic defect gene)
PHA Carrier Bull x PHA Free Cow =
50% PHA Carrier Calves (Normal calf but has recessive genetic defect gene)
50% PHA Free Calves (Normal calf with no recessive genetic defect gene)
PHA Free Bull x PHA Carrier Cow =
50% PHA Carrier Calves (Normal calf but has recessive genetic defect gene)
50% PHA Free Calves (Normal calf with no recessive genetic defect gene)
PHA Carrier Bull x PHA Carrier Cow =
25% Dead Calf and possible dead cow (lethal combo of 2 recessive genetic defect genes)
50% PHA Carrier Calves (Normal calf but has recessive genetic defect gene)
25% PHA Free Calves (Normal calf with no recessive genetic defect gene)
