Location: Livestock Nutrient Management ResearchTitle: Effects of diet quality on energy metabolism and methane production by beef steers fed a warm-season grass-based hay diet
|COLE, N. ANDY - Retired ARS Employee|
|Neel, James - Jim|
|Turner, Kenneth - Ken|
|JENNINGS, TRACY - Texas A&M Agrilife|
|JENNINGS, JENNY - Texas A&M Agrilife|
Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2020
Publication Date: 10/1/2020
Citation: Cole, N., Meyer, B.E., Parker, D.B., Neel, J.P., Turner, K.E., Northup, B.K., Jennings, T., Jennings, J. 2020. Effects of forage quality on energy metabolism and methane production by beef steers fed a warm-season grass-based hay diet. Applied Animal Science. 36:652-667. https://doi.org/10.15232/aas.2020-02025
Interpretive Summary: Methane is a greenhouse gas that has been linked to climate change and global warming. During the food digestion process, cattle belch a large amount of gas through the mouth. This gas is composed primarily of methane and carbon dioxide. Little is known about how the nutritional quality of hay affects methane production from grazing beef cattle. Scientists from USDA-ARS (Bushland, Texas, and El Reno, Oklahoma) and Texas A and M AgriLife Research (Amarillo, Texas) conducted live animal experiments to quantify methane emissions from beef cattle fed hay diets with varying nutritional quality. Nutritional quality was quantified by the amount of crude protein in the hay. Cattle fed a high-quality hay diet produced less total methane per unit of digested organic matter than the low-quality hay. Methane emissions from grazing cattle were higher than cattle fed a high concentrate corn diet in the feedlot. Diet manipulation can be an effective method for reducing emission of greenhouse gases from cattle.
Technical Abstract: The objective was to determine the effects of forage quality and protein supplementation of a low-quality warm-season forage diet on energy metabolism and enteric methane emission of growing beef steers. Eight British cross bred steers were used in a replicated 4 x 4 Latin square design respiration calorimetry study. Experimental diets were: 1) a low-quality bluestem (Bothriochloa ischaemum) hay-based diet (LoQ: 7.4 percent crude protein [CP], 66.6 percent neutral detergent fiber [NDF]); 2) the low-quality bluestem hay with supplemental cottonseed meal (LoQ-CSM: 10.0 percent CP, 66.3 percent NDF); 3) a medium-quality bluestem hay-based diet (MedQ: 10.5 percent CP, 65.0 percent NDF); and 4) a high-quality bluestem hay- based diet (HiQ: 13.0 percent CP, 58.4 percent NDF). Organic matter, fiber, energy, and protein digestibility and energy retention increased as old world bluestem grass quality increased. Total methane production was not affected by forage quality but methane production per unit of digested organic matter or digested fiber decreased with increased forage quality. Protein supplementation of the low-quality grass hay increased dry matter, fiber, and protein digestion and dietary digestible and metabolizable energy, but did not affect methane production. However, methane production per unit of energy and protein retained was increased by protein supplementation. Methane and carbon dioxide emission measured using an outdoor automated head box system gave results similar to the respiration chambers.