September 05, 2013

Feed efficiency in cattle increased when grown in grazing-based system, study shows


By Anne Zinn

According to a recent study, beef production has the potential to be more efficient if farmers focus on the relationship between residual feed intake (RFI) and the selection of certain genes in beef cattle. This research, originally published in September 2013 in the Journal of Animal Science, can help reduce the overall cost of beef production and farming expenses.

In the United States and Uruguay, 65% of farming expenses in beef production is associated with feeding. Currently, cost and efficiency is a major concern in cattle production. Improving feed efficiency is a major goal for cattle breeders because it will help optimize overall beef production, reduce methane production, and make beef production more sustainable.

This study, conducted by the Departamento de Producion Animal y Pasturas and the University of Wisconsin-Madison, hypothesizes that “the combination of the single nucleotide polymorphisms (SNP) of potentially contributing genes (neuropeptide Y, leptin, and IGF-1) may be associated with RFI under sequential feeing conditions,” (Trujillo et al).

The objective of this study was to compare two groups of Angus female calves in order to determine the most efficient feeding process based on body weight and growth rate. The first group of calves contained the favorable genes and the second group was devoid of such genes. Each group was subjected to two different conditions, the first being fed a high concentrate diet in confinement, and the second grazing on a high-quality, high-availability pasture. Two consecutive experiments were conducted from June to December.

The conclusion to this study shows there is a strong association between the three valuable genes (neuropeptide Y, leptin, and IGF-1) and RFI when animals were grazing on a high-quality, high-availability pasture whereas a weak effect was observed under confinement.

The results of this study demonstrate a significant overall association between selected genes and feed efficiency as measured by RFI. This research can help in the understanding of potential candidate genes that can influence RFI traits, especially in beef cattle grown in grazing-based systems and may help improve the cattle production industry positively.

This study is titled “Association of SNP of neuropeptide Y, leptin, and IGF-1 genes with residual feed intake in confinement and under grazing condition in Angus cattle.” It can be found at

Scientific Contact:
Dr. A. I. Trujillo
Universidad de la República

Media Contact:
Anne Zinn