SHEEP producers in western states can get a better idea of which breeds are best suited for their operations based on a comprehensive U.S. Department of Agriculture evaluation of the animals used to produce market lambs.
Researchers with USDA's Agricultural Research Service (ARS) and their university colleagues examined critical performance traits of lambs sired by rams of Columbia, Suffolk and Texel breeds and a composite breed developed at the ARS Roman L. Hruska U.S. Meat Animal Research Center in Clay Center, Neb.
The team included ARS geneticists Tim Leeds, Michelle Mousel and David Kirschten and Virginia Tech professor emeritus David Notter.
In the study at the ARS U.S. Sheep Experiment Station near Dubois, Ida., the group evaluated lamb survival, growth, body composition, efficiency and carcass merit and value.
Rams from each breed were mated to Rambouillet ewes, producing more than 1,800 lambs over a three-year period. Suffolk-sired lambs were larger at birth, grew faster and had a survival rate as good as or better than other crossbred lambs.
After weaning, lambs were fed a high-energy diet and weighed weekly. Suffolks had the most rapid gains and most desirable leanness and were equal or superior to other lambs in growth, fat depth and loin muscle area.
When examined for feed efficiency, Suffolks also scored better than other breeds. Columbia-sired lambs required more than 15 lb. of additional feed than other groups, ARS said.
At comparable market weights, Texels had heavier carcass weights and larger loin muscle areas but were also fatter than lambs sired by the other breeds, the agency reported.
While the Suffolk breed scored the highest in most performance traits, other breeds still have desirable qualities. The Texel can produce heavily muscled lambs that are ready for market at younger ages. The Columbia is valuable for wool production and might be used as both a maternal and sire breed. The composite, developed mainly as a genetic resource, may be useful in stressful production environments that favor a lamb with intermediate growth potential, ARS explained.
Scientists are developing new germplasm resources in an effort to capture each breed's positive traits and incorporate them into a higher-performance breed, the announcement concluded.