Effects of changes in finishing diets and growth technologies on animal growth performance and the carbon footprint of cattle feeding: 1990 to 2020

Authors: CRAWFORD, DAVID - West Texas A & M University; HALES, KRISTEN - Texas Tech University; SMOCK, T - West Texas A & M University; COLE, N - Retired ARS Employee; SAMUELSON, KENDELL - West Texas A & M University

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2021
Publication Date: 1/28/2022
Citation: Crawford, D.M., Hales, K.E., Smock, T.M., Cole, N.A., Samuelson, K.L. 2022. Effects of changes in finishing diets and growth technologies on animal growth performance and the carbon footprint of cattle feeding: 1990 to 2020. Applied Animal Science. 38:47-61. https://doi.org/10.15232/aas.2021-02199.
DOI: https://doi.org/10.15232/aas.2021-02199

Interpretive Summary: Emissions of greenhouse gases from agriculture production are a growing concern. The objective of this study was to estimate the impacts of changes in feedlot diets and the availability of performance-enhancing technologies on growth performance and the carbon-footprint of cattle feeding between 1990 and 2020. Scientists from ARS (Bushland, Texas), Texas Tech University and West Texas A&M University used a model to evaluate changes in the carbon footprint of finishing cattle in 1990 versus 2020. Feedlots in 2020 produced 48% more body weight gain with 7% fewer cattle, while increasing total greenhouse gas production by 23%. Thus, changes in feedlot management have improved efficiency and reduced the carbon footprint of beef production in the past 30 years.

Technical Abstract: The objective of this study was to estimate the impacts of changes in feedlot diets and the availability of performance-enhancing technologies on growth performance and the carbon-footprint of cattle feeding between 1990 and 2020. A model was developed to represent feedlot diets and technologies used in 1990 vs. 2020 and evaluate changes in growth performance and carbon footprint. Byproduct feeds became more common between 1990 and 2020 therefore corn and dry roughage inclusion rates decreased. Estradiol-only implants and monensin were the available technologies in 1990; whereas in 2020 use of implants with combinations of trenbolone acetate and estradiol, monensin, and ractopamine hydrochloride (in the final 28 to 42 days) were common. In both 1990 and 2020 use of all available technologies increased final body weight, average daily gain, feed efficiency, and hot carcass weight compared to no technology. From 1990 to 2020 initial body weight, final body weight, average daily gain, gain to feed ratio, and hot carcass weight increased, and dry matter intake decreased. Total days on feed increased by 43 days from 1990 to 2020. Compared to no technology, use of technologies in both 1990 and 2020 decreased total greenhouse gas emissions per animal. Because cattle had greater days on feed in 2020, all sources of greenhouse gas emissions per animal increased compared to the values estimated in 1990. However, when expressed as carbon dioxide equivalent per kg body weight gain, emissions have decreased by 12.6 percent because of greater total body weight gain in 2020 versus 1990. Feedlots in 2020 produced 48.15 percent more body weight gain with 6.7 percent less cattle, while only increasing total by carbon dioxide equivalent 23.42 percent, indicating changes in available technologies and diet formulations have improved efficiency and reduced the carbon footprint of feedlot cattle production in the past 30 years.