Lay Summary Feed efficiency is an important trait in cattle production because it influences the amount of feed required to achieve growth and therefore impacts both production costs and environmental sustainability. One way to measure feed efficiency is through residual feed intake (RFI), which compares an animal’s actual feed intake to what would be expected for its body size and growth. Animals with low RFI are considered more efficient because they eat less food than expected while maintaining growth. In this study, we evaluated 302 young bulls to identify blood compounds linked to differences in feed efficiency. The most efficient and least efficient animals were compared for a wide range of blood metabolites and hormones. Our results showed that efficient and inefficient bulls had different patterns of certain blood compounds, especially those related to lipid metabolism and bile acid production. We also identified a few specific compounds, including choline and some types of fats, which may serve as biomarkers to predict feed efficiency. While the overall predictive models were limited, these findings highlight the potential to use blood tests to better understand and eventually improve cattle feed efficiency.
Venturini et al. (Fri,) studied this question.