Performance Line
Modern Limousin Genetics: A Good Story for Feeder Calf Value
By Tonya Amen, National Center for Beef Excellence
Long known for their value as terminal sires, Limousin breeders have maintained the genetic value for those traits of interest, while also focusing on traits like docility that are important to their commercial customers and, as the industry has demanded, recent emphasis has been placed on marbling as well.
Much of this discussion will center around a look at genetic trend in the North American Limousin population of the last 20 years. Genetic trend is typically illustrated in charts like those in this article or in tables organized by year. Genetic trend charts and tables are simply the average EPD for animals born in each year for each trait. When evaluated over the years, a picture emerges of the traits that breeders have chosen to place selection emphasis on.
Limousin bull is expected to sire progeny who are nearly 11 percent more likely to have an acceptable temperament.
Table 2 shows the genetic trend for carcass traits from 1998 to present. While holding REA and FT fairly constant, carcass weight has increased drastically, a definite win for an industry paid on pounds. Additionally, it’ s clear that recent focus has been placed on improving marbling, with a 64 percent increase in the average EPD since 1998, with upward pressure accelerating in recent years. As quality grade continues to grow in its importance from a profit standpoint, this is a trait that should receive continued focus.
Table 2: Genetic Trend – Carcass Traits( from summer 2018 BOLT evaluation)
For example, Table 1 is an excellent illustration of what can happen when, as a group, breeders decide to make genetic improvement in a trait and use all the tools at their disposal to do so. Early on, Limousin breeders recognized that to meet the demands of their commercial customers, docility needed to be addressed. In the last 20 years alone, there has been a 130 percent increase in the average docility EPD. When put into practice, this means that compared to 1998, the average
Table 1: Genetic Trend for Docility( from Spring 2018 NCE)
Table 3 illustrates the percentile ranks for NALF EPDs, as well as for some other British and Continental breeds. The vertical lines or“ whiskers” on the plot show the variation in genetics for marbling among active sires in the breed. It’ s encouraging to note that, while perhaps not reflected in the average, there are clearly active Limousin bulls with excellent genetics for marbling. Identifying and propagating these genetics will only allow for more improvement in
14 | AUGUST 2018