By now, you have realized that Genomics
offered nothing we did not already have—it just accelerated the turnover rate
of sires available in most AI systems. Because of its heavy (40%) reliance on parent
averages, the pedigree pathways in genomic breeds are getting narrower, full
sisters to ranking bulls are now the preferred bull mommas rather than pedigree
outliers. Phenotypic variation is much
reduced, raising worries over the issue of inbreeding depression (canceling out
the potential for genetic gain).
Then enters Zoetis (Genomic division
of Pfizer) with something that does offer us new, useful information on
the relative (genetic) incidence of six costly cow afflictions
whose annual cost to dairying is in the hundreds of millions of dollars—dollars
the current price of milk does not recover.
The best defense against inbreeding effects is to select among
the healthiest and most fertile breeding stock and linebreed desirable
behavior. “aAa” will protect
against inadvertent mating of similar genotypes, while positive selection for
production, reproduction, feed efficiency and health will minimize failures.
No comments:
Post a Comment