Limousin trends favorable for scrotal circumference, docility, carcass traits
Cattle producers can accomplish significant genetic improvement in a short period when using effective selection tools, such as expected progeny differences (EPDs), to deal with moderately heritable traits. The Limousin breed’s phenotypic trends in scrotal circumference (SC), docility and carcass traits illustrate that fact. “Based on documented phenotypic trends, Limousin breeders are using selection and management effectively to produce seedstock with improved performance profiles,” said Kent Andersen,
Ph.D., executive vice president for the North American Limousin Foundation (NALF). “Commercial users of Limousin genetics are the beneficiaries of those breed improvements.”
From 1997 to 2007, Limousin phenotypic trends showed a 2-centimeter increase in adjusted yearling SC, on average, for Limousin and Lim-Flex bulls.
Based on research, producers also can expect an associated improvement in age at puberty in the bulls’ heifer contemporaries.
Similarly, average recorded docility scores indicated an improvement of 0.25 score unit across both sexes over those 10 years, a time frame that coincides with NALF’s genetic evaluation for docility. Limousin breeders have been using docility EPDs in their breeding programs to emphasize selection for calmer animals, and they have improved the temperament of Limousin cattle dramatically.
NALF also studied the trends in yearling-adjusted ultrasound measurements for ribeye area (REA), percent intramuscular fat (IMF, an indicator of marbling) and subcutaneous rib fat. While documenting phenotypic stability for the breed’s industry-leading REA, the organization found encouraging increases in IMF. Bulls improved 0.20 percentage point, while females were up 0.33 percentage point.
The additional 0.06 inch of observed subcutaneous rib fat in both sexes indicates earlier compositional maturity and increased fleshing ability. Those are economically desirable for female adaptability and days on feed for finishing, especially during times of particularity high feed costs, Andersen noted. — WLJ