www.NALF.org

North American
   Limousin Foundation
Suite 100
7383 S. Alton Way
Centennial, CO  80112

(303) 220-1693
fax: (303) 220-1884

NALF Line
May 2007

Don’t Keep Maternal Efficiency a Secret
By Lauren Hyde, Ph.D., director of performance programs, and Brad Parker, director of communications

Scientific evidence shows Limousin females are biologically efficient and flexible enough to thrive under many environmental conditions. They generally are of moderate height and weight and produce medium-sized calves with little calving difficulty. Additionally, the calves are vigorous at birth with high survival to weaning.

Limousin cows also have a long life span. Based on North American Limousin Foundation (NALF) data, cows culled due to age are just older than 12 years on average.

The NALF performance program has addressed cow longevity through its stayability expected progeny difference (EPD). It is a tool for predicting genetic differences in the likelihood that animals will produce daughters that remain in production past age 6. The prolonged, favorable genetic trend in stayability likely results from years of culling open cows, fertility-testing bulls and requiring heifers to calve first at 2 rather than 3 years of age. The trend also shows modern Limousin cattle are reproductively superior to their ancestors.

Yearling Limousin heifers have had a reputation as late-maturing with low pregnancy rates after their first breeding seasons. To help improve age at puberty, NALF introduced scrotal circumference EPDs in 1994. As with stayability, scrotal circumference has shown an impressive genetic trend.

In 1999, NALF worked with researchers at Colorado State University (CSU) to develop prototype EPDs for heifer pregnancy, or the probability of a heifer conceiving and remaining pregnant until time of palpation if she was running with a bull while she was in heat. That study showed the heritability of heifer pregnancy was about 0.20.

Because heifer pregnancy appears to be heritable in Limousin cattle, breeders could use such an EPD to improve heifer fertility even further. NALF currently does not have an EPD for heifer pregnancy, however, so it encourages its members to collect and submit female productivity data – particularly through the Limousin Inventory Management System (LIMS) heifer-exposure reporting tool – so it can develop new EPDs that describe the population of Limousin cattle accurately.

Milking ability is another trait for which Limousin females sometimes have gotten a bad rap. Optimum is the key word to use when discussing milking ability, however. Problems are associated with both low and high levels of milk production. For example, cows with extremely high levels of milk have higher maintenance requirements, are harder to breed back on schedule and might have a greater incidence of teat and udder problems.

Limousin females produce moderate levels of milk both early and late in lactation, and they are similar to straightbred Angus cows in both categories. Limousin breeders have made great strides toward improving milking ability.

Genetic improvements in docility also have been substantial over the years, indicating breeders aggressively have culled animals with unacceptable dispositions. More than 60 percent of today’s Limousin sires have a docility EPD greater than 10. Breeders can use those sires to produce replacement females less likely to have temperament problems. No other major breed offers genetic information regarding docility, yet all breeds have lines of cattle with temperament problems.

Efficiency is another strength of Limousin females. They compare favorably to other Continental breeds in the number of calves born per cow exposed and in the number of calves weaned per cow exposed.

While British breeds tend to be more efficient when feed is limited and Continental breeds are more efficient when feed intake is high, Limousin cows are highly efficient in either case. That suggests Limousin females are more flexible than females of other breeds – being able to adapt more readily to changing feed resources in changing environmental conditions.

Limousin genetics offer value not only in carcass traits but also in maternal traits. With their moderate size, long life span, optimum level of milk production and biological efficiency, Limousin cows are an excellent choice under a wide variety of production environments and market targets.

Limousin breeders need to continue selecting for easy calving; moderate size; optimum milk; and high fertility, docility and stayability. Then you need to promote those favorable attributes among the rest of the beef industry.