Monday, January 4, 2021

Why would a grazier use “aAa” Breeding Guide (Weeks Analysis) ?


When “aAa” (Animal Analysis Associates) began in 1950, AI was in its infancy with fresh semen, and the vast majority of dairy (and beef) cattle were eating grass in pastures.    Some got baled hay and corn stover; a few got corn silage, the rest got forage beets and maybe a coffee can of dry grain mix at milking.     The average dairy milked 18 cows, and milk was shipped in cans.

“aAa” began ten years before frozen semen made the genetics horse-race possible, as a system that was based in Bill Weeks’ observations of how physical traits pass between generations. Bill’s genius was to translate biology into a method any cattleman could follow with guidance.  

The obvious success of “aAa” led to breed associations and AI marketing developing their own “mating” services, based on the linear type traits developed for computers in the early 1970s.   Now with herd sizes averaging 50 cows, we all had less time to make these decisions ourselves.    “aAa” held its own against all the new linear and genetic mating, because it still worked.

Ironically, scientific study of the results of linear trait mating could not prove any improvement in dairy herds beyond the differences in sires.   Evaluation is good at telling us the “results” of a mating, but it failed as a “predictor” of how to breed a better herd—in part because measuring the extent of a trait does not recognize the cause of the defective trait expression.     

The industry view is simple.    Whether indexing or crossbreeding, we tend to choose “one size fits all” solutions, as if cows reproduced by cloning.    We forget that two genotypes (cow and bull) combine at each conception, and a unique new genotype will result… Thus no matter how sires are ranked, depending on those numbers alone leads to “single trait selection”, proven as the cause of inbreeding “depression”.     Selection and Mating prove to be separate functions.   

When it comes to grazing and grass dairy, when the cow environment changes daily, that need for physical uniformity requires matings that produce a highly adaptable physique, able to deal with daily and seasonal changes over each cow’s lifetime.    The more physically extreme cows being bred today through “one size fits all” sire indexes do not have that adaptability;  they are designed for a high input, fed TMR in place, year-round barn environment.    For grazing, we go a different direction, adding dimensions that corn-bred TMR cows increasingly lack.

“aAa” Breeding Guide (Weeks Analysis, in Europe) provides the control you need to breed the cow you want, specific to your environment and market opportunities.   Using “aAa” principles today will produce efficient-size cows with optimum forage capacity tomorrow.    It has proven sustainability over multiple generations, avoiding inbreeding depression, as you would expect for a program that thrives (without industry subsidy) 70 years after it was first introduced.

Don’t take my word for it.   Ask around the conference – see what aAa users think.   Then make your own decision.   You may find breeding improvement is easier to manage than you thought.

by Greg Palen                  “aAa” customer since 1978, “aAa” associate/analyzer since 1994.

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