It is one of the great ironies of the
current club-calf scene, that “hair” may be the primary selection trait.
Not “beef” yield, for edible meat
cuts; not “hides” for leather; not “bones” for fertilizer. Just inedible and unsalable “hair coat”, so
important to the final fitting process at our club shows and sales.
Why do I bring this up? Not necessarily because of “certified Angus
beef” which has created a demand for “black” cattle, earning slaughter market
premiums in hopes that the promoted carcass advantages of Angus would be
present.
No, it is because of the latest trends
in Genetic (genotype, genomic) DNA research.
Black coloration of cattle is due to
the presence of the MC1R (Melanocortin 1 Receptor) gene, which encodes a
receptor located on Chromosome 18 that is needed for black pigmentation “and
also has other functions” according to two researchers at Iowa State
University college of Veterinary Medicine.
Black (MCR) is always dominant to the
other alleles at the E locus. Non-black
(mcr) color is recessive (which is why other breeds, red, yellow, with or
without white spots turned black so easily when bred to Angus to gain that
black hair coat). Like the black hair
gene, the non-black gene has other functions which the ISU-CVM research find to
be very beneficial.
It seems the “non black” cattle have a
gene-encoded resistance to Salmonella and E.-Coli infections. If exposed to either of those lethal
diseases, their genotypes have natural resistance; if vaccinated against these pathogens they
develop useful titres; if treated with
antibiotics they metabolize them faster (which reduces withdrawal times) and
they have a higher pain threshold (less likely to go off feed when ill).
Ironically, this DNA capability is
lacking in the MC1R gene which provides the black hair. Therefore, breeding for “black” in all the
non-black hair breeds has passed a latent genetic effect across 70% of the
total beef cattle population in the USA.
Genomics started out as a way to
predetermine genetic values from DNA samples prior to actual animal performance
and subsequent data evaluation. These
uses matured fairly quickly; now the bulk of DNA research is seeking out
answers to more physiological and health-related issues such as ability to get
an immunity from vaccination, or response to various drug therapies for typical
herd problems.
Dominant and Recessive gene activity
was already known in all breeds (dominant polled vs recessive horns; dominant black vs recessive red hair) but now
we are finding cases of linkages of effects as in this occlusion between black
hair and specific disease susceptibility.
Possible benefit to non-black breeds
The popularity of non-black cattle is
greatest in commercial beef production, often the range managed herds, where
minimum human handling is possible.
Could better health experience be part of this ??
The cattle industry has always
included highly observant breeders alongside data driven commercial producers,
with some synergy resulting (given 90% of range cattle are bred naturally, only
10% AI).
It remains for our club calf judges to
open up the opportunity for good red, roan, yellow, white cattle.
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