Wednesday, May 15, 2024

WEIRD TRENDS IN HOLSTEIN CATTLE that are causing trouble

  CONCEPTIONS  Dairy Route Newsletter               May-June 2022

Many of you have never asked why I keep promoting the “aAa” Breeding Guide.   I also know that the typical AI stud salesman calls what we do “voodoo” as if it had no basis in the biology of gene transmission and genotype repairing.    In fact, aAa has always had the most provable explanation of why linear-based matings can go wrong and produce early-age culls from what were supposed to be the “best” sires (and for which you probably paid a premium price).

Here are some examples:


Many of the “elite” sire lines based on both the “Net Merit $” index and Holstein “TPI” index have been “erasing” the rear teat on your replacements, frequently producing udders lacking enough rear teat to seal a teat cup for milking   

Biological cause:  lack of aAa quality #1 “Dairy”  
Selection cause:  as Genomics accelerates sire generations in favor of “health” it has reduced the hormone production in heifers that would complete developing a full capacity udder.    


AI studs have dreamed up “robot ready” designations to indicate the handful of sires that usually still have space between two rear teats.     The problem begins when the udder lacks any rear udder width.    Teats just ride on the outer skin of the udder; they will only be spaced when a rear udder has adequate “room”.     

Biological cause:   lack of aAa quality #5 “Smooth”
Selection cause:  as Genomic selection has tied faster adolescent growth rates and earlier-age maturity of production together, animals do not develop width or spring of rib that assists the rumen in full utilization; they just grow excessively tall and the stretched muscling flattens against the skeleton.    Narrowness results.

Often seen on the heifer who is narrow in her front end.    When you look at the way she stands at rest, her front feet “toe out” to the extent her lower leg turns.   You will see most of her weight is carried on the inner toes, allowing uneven hoof wear.   Outer toes grow out requiring frequent trimming.    She goes lame.

Biological cause:   lack of aAa quality #5 “Smooth”
Selection cause:   linear type for decades has confused “angularity” with “dairy”.    This has produced narrower front ends over time, until the frame can no longer anchor legs squarely at four corners of a physically balanced body core.


The hind leg position on such cows does not support the full rear end weight, due to a thurl position that thrusts the hind leg out partially behind the rump.   Loins flatten out, spines bend, and locomotion declines as spinal nerves get pinched.

Biological cause:   lack of aAa quality #6 “Style”
Selection cause:   linear type for decades has wavered between preference for a “set” hock and a “straight” hock, often ending up with extremes of each.    This is an added consequence of “angularity” selection, which reduces muscle mass the cow needs to hold the thurl central to the rump and fully control the foot.


If hind legs are too close to the udder, the maturing of the mammary gland will force it outside the housing provided by the pelvis.

Biological cause:    lack of aAa quality #3 “Open”  AND  lack of quality #1 “Dairy”
Selection cause:   linear type focuses more upon the rib cage, less on the pelvic dimensions, starting at the hip (hooks downward) and proceeding through thurl and pins.    Fancy snug young udders end up either deep or tilted forward, each of which reduces milkability of the udder with each added calving.


I COULD GO ON …  my point is, sound matings would PREVENT making such cows.




No comments:

Post a Comment