Methane emissions from cattle differing in feed intake and feed efficiency fed a high concentrate diet

Authors: Freetly, Harvey; Brown-Brandl, Tami

Submitted to: Western Section of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/25/2011
Publication Date: 6/1/2011
Citation: Freetly, H.C., Brown Brandl, T.M. 2011. Methane emissions from cattle differing in feed intake and feed efficiency fed a high concentrate diet. Proceedings of the Western Section of the American Society of Animal Science 62:314-317.

Interpretive Summary:

Technical Abstract: Methane gas released by cattle is a product of fermentation of feed in the digestive tract and represents a loss of feed energy. In addition to being a dietary energy loss, methane is considered a greenhouse gas. Developing strategies to reduce methane emissions from cattle have the potential to increase production efficiency as well as reduce the impact of cattle on the environment. We hypothesized that steers with a higher feed efficiency would have a lower methane production. One hundred thirteen steers were fed a dry-rolled corn-based ration to determine feed intake and growth over a 64-d period. Steers had ad libitum feed access (82.75% corn, 12.75% corn silage, and 4.5% Biegerts, Bradshaw, NE (contains 0.066% monensin)), and feed intake was calculated as the sum of feed intake over the 64-d period. Steers for methane emissions measurement were selected by regressing gain on feed intake and selecting the 40 steers that were outside the 60% elliptical confidence interval. Thirty-seven of the 40 selected steers were chosen to measure methane emissions based on their temperaments. Five d following the collection of growth and feed intake data, methane emissions were determined over a two-wk period using indirect calorimeters (headboxes) to determine gas exchange. A six-hr sampling period was chosen to mitigate the potential reduction in feed intake during sample collection. Collection began at 0800 when fresh feed was offered. Steers had ad libitum access to feed and water during gas collection. Residual feed intake was determined as the residuals resulting from the regression of feed intake on ADG, and middle metabolic body size (R2 = 0.70). Steers that were evaluated had a methane emission of 2.6 ± 0.1 g/h, a BW of 573 ± 12 kg, a DMI of 696 ± 17 kg/64 d, a gain of 104 ± 3 kg/64 d, and a residual feed intake of -0.1 ± 0.1 kg. Methane emissions did not differ with DMI (P = 0.52) or gain (P = 0.26). Methane emissions did not differ with residual feed intake (P = 0.88). Our findings do not support that variation in methane emissions from cattle fed high-corn diets containing monensin can be explained by DMI and gain.