February 15, 2004
Feb. 2004 -- The term ?composite? has been a buzzword in the cattle business for some time now. Many sheep producers don?t realize there are composite sheep breeds in the world, too.
Dr. Dan Waldron, Texas Agricultural Experiment Station research geneticist, said a composite breed is a carefully planned crossing of two or more different purebreds done to enhance specific desirable traits. Subsequent offspring from these animals are interbred to produce a composite breed.
This subsequent crossbreeding is the major difference between a composite and a crossbred animal. The Santa Gertrudis and Beefmaster cattle breeds are all composites. On the other hand, the common ?black-baldie? is a crossbred between a Hereford and Angus.
Thanks to Waldron, the Texas A&M University System Agricultural Research and Extension Center at San Angelo is beginning work with a composite terminal sire breed to be crossed with native Rambouillet ewes. His aim is to see how the composites compare with Suffolk rams, the sire of choice for most West Texas ranch crossbreeding programs.
?Many West Texas sheep operations routinely use Suffolk rams as terminal sires in their Rambouillet ewe flocks,? said Waldron. ?Their aim is to produce superior market lambs with the added benefit of hybrid vigor. A terminal cross is one where all the lambs are sold. None are kept for breeding purposes.
?Hybrid vigor occurs when two significantly different breeds are crossed. This cross usually results in an animal that it more vigorous and grows faster than either of its purebred parents. Since all the lambs resulting from a terminal cross are sold at a young age, wool production is not a concern. Lamb survival, growth rate and carcass composition are the moneymaking traits the rancher is after.?
Waldron said that West Texas producers have traditionally thought of the Suffolk as the breed of choice to cross with Rambouillet ewes for market lamb production. But he?s always been curious about how a good composite sire breed would compare under West Texas range conditions. Over the next two years he plans to find out.
?In 1980, the USDA?s Meat Animal Research Center at Clay Center, Neb., began developing a composite terminal sire breed,? he said. ?This composite was developed from Columbia rams bred to Hampshire x Suffolk ewes. The flock has been closed for several years, meaning no outside animals have been introduced. This flock has been intensely selected and bred for growth rate and carcass quality, the prime traits of a good terminal sire.
?The Suffolk rams we?re comparing the composites with came from area producers who have supplied rams to many ranches across the region for years.
?We have a group of uniform Rambouillet ewes on our range station near Barnhart. Four composite rams will be bred to half of that group of ewes. The other half will be bred to Suffolk bucks. This project started with the bucks being put with the ewes in October. The lambs will be born in March and April of 2004. We will wean those lambs in the summer, feed them, measure their growth rate, and finally slaughter them and measure their carcass traits.
?The most important factors in this study are:
- The number of lambs produced. Is lamb survival greater in one breed than in the other?
- The number of lambs weaned. Both lambs produced and weaned will be important to the producer?s bottom line because he can?t market what he doesn?t have.
- Carcass traits. We?ll follow these lambs through the feedlot to measure growth rate on through slaughter to test their carcass quality. Again, the bottom line says that the better quality animals will bring the producer the most money.
?We plan to follow this project through two lambing seasons. It should be interesting to see how the composites stack up against our native Suffolks,? said Waldron. ?Other breeds have been used here in the past with mixed results. To date, producers have always returned to their tried-and-true Suffolks.
?I?m excited to see how these newcomers will fare on our harsh range conditions,? Waldron said. ?If they do well, the term ?composite? may become as common in the sheep industry as it has in the cattle business.?