Dr. Bob Hough, WLJ correspondent |
In the last several years, the production of a Stayability EPD has been given an increasing amount of attention by the beef industry. Today most breeds are either publishing the genetic predictions or are in the process of developing a genetic prediction for sustained fertility. Despite the flurry of recent activity around the trait, Stayability has actually been around for 25 years, having first been published in 1995 by Red Angus.
The trait Stayability is defined as the probability of a cow that calves as a 2-year-old will remain in the herd calving at 6 years of age or older. This assures that cows in a commercial herd last long enough to be profitable. Its importance is demonstrated in indexes, which have a maternal component, where Stayability is routinely identified as the most economically important trait, and given the most weight in an index.
Stayability’s economic importance was elaborated upon in 2006 by Dr. Dorian Garrick. He listed the advantages of high Stayability cattle including: “Cows that are able to stay and produce longer, affect beef herd productivity through a decreased need and cost for replacement, less calving difficulty, more sale offspring with heavier weights, and greater average weaning weight.” Dr. Matt Spangler of the University of Nebraska also points out that the real costs of cow herd depreciation, and culling cows before they are fully depreciated represents an economical loss to a commercial producer.
However, the problem with the Stayability genetic prediction has always been its low accuracy until a sire is relatively old and generally past its productive lifespan. This is because by the time a sire’s first set of daughters reach 6, the bull will be at least 8 years old. Therefore, the model has been under continuous improvement since first released in 1995.