Friday, November 18, 2016

The “genetics” of hoof trimming

A majority of dairymen today have a hoof trimmer on call, in fact may have a regular monthly or weekly hoof trimming day.    The growth of demand for hoof trimming is usually blamed on three things:  (1st)
“Cows milk more than they used to, eat more grain, making their hooves grow out more”.   (2nd)  “Cows are walking less, mostly on wet concrete, keeping their feet soft and vulnerable”.   (3rd)   “Heel warts and hoof rot are everywhere, and don’t go away until treated and wrapped”.

A study done in Utah and Idaho in 2013 on heel warts

A major distributor of improved foot bath solutions wanted to understand why hoof problems recur even when hygienic solutions are being used.    They visually observed 16,000 cows over six months in large herd systems, and ultimately stumbled on a startling observation:
The weaker the front end structure of the cow, the higher the frequency of heel warts.

Foot angle didn’t matter; Set of rear hock didn’t matter; level of production didn’t matter.     Cows with “strong” front ends had the least heel warts observed, while cows with “frail” front ends had the most.
Note:  the designation of “strong” or “frail” was based on the “aAa” concepts of physical qualities.

Why does a “strong” front end lead to a “strong” foot on a cow?

This is the interrelationship of parts to function.    aAa “strong” (code 4) is a full, deep chest, which is the best visual indicator of high heart function.    The heart circulates oxygenated blood to the internal organs and external muscles of the cow.    For a cow to resist heel wart virus’ or other foot infections, she must have good blood flow to reach extremities like the hoof.    It is also noted that ‘strong” cows will have harder horn (hoof) tissue, thus protecting the sole underneath and resisting soft toe growth.

An observation of feet that refuse to grow evenly

The selection tendency toward narrower cows in high input, high feed energy dairies has produced a lot of cows who stand on uneven feet.     Looking particularly at front feet, you will see the outside toe is bigger (in both depth and length) than the inside toe, which appears to be carrying the most weight.   It is not unusual for such cows to “toe out”—and you lead them to the hoof trimmer each time he comes, in hopes he can make the cow “stand straight”.

By contrast, cows with some width of chest tend to stand sturdy, and the toes on their feet will be equal in size (inner and outer toes evenly formed and wearing evenly).    

Why does a “wide” front end lead to a “healthy” foot on a cow?

In another functional interrelationship, the aAa “smooth” (code 5) cow is more “balanced” in position of all four legs to stand the full width of the cow’s body, allowing for a straighter track and sturdy stance which, in combination, avoids uneven weight distribution side to side on the hoof.    Beyond that, wider chested cows (with wider heads) can breathe more fully and deeply, thus providing more oxygen in the lungs for reoxygenating the blood flowing to the legs and feet, aiding them in staying healthy.


Is your approach to mating using all the foot and leg information needed to breed better mobility ??

Harvesting all the genetics you select

Genetic selection when done well sets you up with the possibility of better production from healthier cows.

Mating that considers gene interrelationships in cow physiques sets you up to harvest genetic potential at an optimal level.

Random mating (the total population average) assumes the current (genomic) generation matches up equally with the prior (evaluation) generation, in spite of having transformed genotypes.    Thus 40% of the results are generally culled as failures (extremes).

If you are tired of 40% culling to harvest 60% of genetic potential, consider the effect of physical quality selection as a superior way to mate your cows to ranking bulls.

Mich Livestock Service, Inc    “For the Best in Bulls”    Independent AI genetic supplier    (800) 359-1693

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