University of Missouri
The project assembled DNA samples, individual feed intake, growth and carcass data for 8,000 animals from 8 major beef breeds.The project has various objectives, including identifying genes with different levels of expression between high-efficiency and low-efficiency animals, create genomic predictions for feed efficiency, and identify DNA variants responsible for differences in feed efficiency (causal variants).
The project collected 12 Angus sired steers, 12 Charolais sired heifers and steers, and 12 Hereford sired steers, half of which had poor feed efficiency and good feed efficiency. They collected over 15 tissues per animal.
In the Hereford RNA sequencing data, the team found genes that are involved in metabolism. In the Angus and Charolais data they found many genes involved with immune function. This is likely due to the poor feed efficient animals having subclinical illness which led to them having poorer performance and less efficiently turning feed into gain.
The project showed that feed efficiency and its component traits are highly heritable. There are also many relatively large effect genes (quantitative trait loci) for all traits. Many of these stretches of DNA (quantitative trait loci) affect multiple traits and are shared among breeds.
The project is continuing to search for causal variants (the DNA variants responsible for variation in traits).
In order to continue to use the resources generated by the feed efficiency project, industry must continue to collect intake and growth data, and DNA samples.