Title: Relationship between selection for feed efficiency and methane production Author
Submitted to: Beef Improvement Federation Proceedings
Publication Type: Literature Review
Publication Acceptance Date: May 30, 2014
Publication Date: June 9, 2014
Citation: Freetly, H.C. 2014. Relationship between selection for feed efficiency and methane production. Proceedings of the 46th Beef Improvement Federation Annual Meeting and Research Symposium, June 18-21, 2014, Lincoln, Nebraska. p. 112-115. Technical Abstract: Enteric methane is a product of fermentation in the gastro-intestinal tract of ruminants. A group of archaea bacteria collectively called “methanogens” are responsible for the synthesis of methane. In ruminants, the methanogens grow in the reticulum-rumen complex and in the cecum. Most of the methane that a ruminant produces is in the reticulum-rumen, and is released into the environment through the mouth. Most of the methane produced in the cecum is absorbed in the blood and travels to the lungs where it is exhaled during respiration. Methane is a greenhouse gas. Methane represents a lost opportunity to capture feed energy. If captured, this lost energy could potentially be used for maintenance, growth, and lactation. About 3% of intake energy consumed by steers fed a high-corn diet is lost as methane energy. The percentage increases when cattle are eating a high-forage diet. Pregnant beef cows eating a corn silage based diet will release 5 to 7% of their gross energy intake as methane. A potential approach for reducing methane production is to select for increased feed efficiency. Selecting cattle for greater residual gain or greater gain:feed ratios may result in an increase in methane production. Cattle that more completely digest their feed will get more nutrients per unit of feed and produce more methane. Residual feed intake (RFI) is the difference in amount of feed consumed by an animal from that predicted for its rate of body weight gain and size. Negative RFI are more efficient since they eat less feed than is predicted to be needed for a given rate of production. Residual feed intake has been used as a measure of feed efficiency and has been used in selection programs to improve feed efficiency. Selection on RFI decreases feed intake. Cattle selected for low RFI have a reduced daily methane production.