Location: Livestock and Range Research LaboratoryTitle: Composite breeds and genetic stability
Submitted to: Beef Magazine
Publication Type: Other
Publication Acceptance Date: 11/8/2022
Publication Date: N/A
Interpretive Summary: Composite breeds are commonly used in the US beef cattle industry. They provide producers with important benefits such as breed complementarity and retained heterosis. However, cattle composite genomes are not well characterized. In general, producers assume that progenitor breed proportions remain stable in subsequent generations. Composite breeds are usually managed as a single population and artificial selection is applied using phenotypes or genetic merit values. This leads to changes in the progenitor proportions and the overall genome. Additionally, forces such as genetic drift and natural selection also contribute to these changes. In this article, we discuss the genetic changes occurring in some of our present composite populations and the implications of these changes on diversity and production.
Technical Abstract: Composite cattle populations play an important role in global beef cattle production. They enable producers to effectively combine the desirable traits (through complementarity) of progenitor breeds (e.g., Bos taurus and Bos indicus) and take advantage of hybrid vigor and thereby increase productivity. Beef producers in the U. S. have been highly successful in developing new breeds/composites that have found national and global acceptance (e.g., Brahman, Brangus, Santa Gertrudis, Beefmaster). It is important to note that composite breeding is different than crossbreeding. Once the composite is formed and stabilized with the targeted proportions of the founding breeds the resulting animals are mated like any other pure breed. The advantages of composite development are multiple purebred populations do not need to be maintained to form the crossbred, nor do they require separate breeding pastures and variable calf crops. In this article, we discuss the genetic changes occurring in some of our present composite populations and the implications of these changes on diversity and production.