What’s the Advantage of Large Herds?

There are many reasons why the ADVANTAGE program was setup, but an often overlooked benefit is the advantage of working in a large herd environment. Although there are certainly exceptions to the rule, in general large herds are much more efficient than smaller herds. Like it or not, they are also the future of the dairy industry in the United States. Our partnership with these herds has helped us grow our sales in these herds tremendously, however believe it or not, the real reason for focusing on large herds is genetic...

Large herds not only provide a very similar environment for progeny testing as our other large-herd customers, but when the CORRECT large herds are chosen, they can actually add to the accuracy of genetic evaluations! Whenever genetic evaluations are calculated for a given trait, “contemporary groups” are formed within a herd. These “contemporary groups” (cows included in these contemporary groups are often referred to as “herdmates”) are generally formed using cows within the same herd, the same lactation, and the same two-month period of freshening. Therefore all cows fresh between 1/1/05 and 2/28/05 within the same herd and the same lactation, would be considered a contemporary group. When genetic evaluations are calculated, averages for each contemporary group are calculated for all traits of interest, and each cow within that contemporary group “deviates” from that average. Therefore if the group average for a given contemporary group is 24,000 lbs of milk, and one cow from that group produces 25,000 lbs of milk, then she has a +1,000 lb deviation. The same goes for traits like productive life – if the contemporary group average is 3 lactations (30 months) and a given cow only lasts 20 months, then she would have a deviation of -10 months of productive life.

These deviations are the key to calculating genetic evaluations on our sires, and large herds provide a much larger, and therefore more accurate contemporary group average than smaller herds. In an average 500 cow dairy, approximately 250 heifers will calve each year, which amounts to about 20/month. That means the average contemporary group size in these herds is over 40 animals! With 40 animals we have a much more accurate “baseline” to judge the deviation of our YS daughters on… leading once again to more accurate proofs!

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Posted Feb 3rd

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