Wednesday, November 1, 2017

Understanding TH and HCA recessives


Recessives are somewhat simple—if momma carries it, and daddy carries it, you have a 50-50 chance the calf will exhibit it.     Those recessives noted as “lethal” cause death.

If you wish to avoid ever having a TH or HCA afflicted calf, just avoid using carrier bulls on any daughter of a known carrier.

What is “TH” recessive?      Stands for “Tibial Hemimelia”    (origin in Shorthorn breed)
Calf will exhibit abdominal hernia, distorted pelvis and rear legs, exposed brain and/or spine tissue.
Such calves if born alive tend to die soon after birth.

What is “PHA” recessive?    Stands for “Pulmonary hypoplasia and Arasarca”   (origin Maine-Anjou)
Calf will have small lungs, filled with fluid, and will lack lymphatic system develop.
Such calves tend to be stillborn;  a certain percentage of such conceptions may abort prior to term.  

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