|GENTRY, WES - Agrilife Research|
|WEISS, CALEB - Agrilife Research|
|MEREDITH, COLLENN - Agrilife Research|
|MCCOLLUM, TED - Texas Agrilife Extension|
|COLE, NOEL - Retired ARS Employee|
|JENNINGS, JENNY - Agrilife Research|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2016
Publication Date: 10/27/2016
Citation: Gentry, W.W., Weiss, C.P., Meredith, C.M., Mccollum, T.F., Cole, N.A., Jennings, J.S. 2016. Effects of roughage inclusion and particle size on performance and rumination behavior of finishing beef steers. Journal of Animal Science. doi:10.2527/jas.2016-0734.
Interpretive Summary: When expressed per unit of available energy, roughage is the most expensive ingredient added to beef cattle finishing diets; however, some roughage is needed in finishing diets to promote rumen health and prevent digestive upsets. Because of the wide variety of roughages available (grass hay, alfalfa hay, corn and sorghum silages, corn stalks, cotton gin residue, etc.) the optimal quantity and quality of roughage needed in the diet is still not well defined. This study was conducted to evaluate the effects of corn stalk inclusion rate and particle size on rumination behavior, animal performance, and carcass characteristics with steers fed one of three diets. Based on screening methods, the long grind corn stalks contained more physically effective fiber than the short grind corn stalks. Results indicated that increasing particle size of roughage may be a means to decrease roughage inclusion rate in beef cattle finishing diets while maintaining rumen health and animal performance.
Technical Abstract: Roughage is mechanically processed to increase digestibility, and handling and mixing characteristics in finishing diets. Roughage is fed to promote rumen health and decrease digestive upset, but inclusion in finishing diets is limited due to the cost per unit of energy. Rumination behavior may be a means to standardize roughage in beef cattle finishing diet, and increasing particle size of roughage may allow a decrease in roughage inclusion without sacrificing animal performance. The objectives of this study were to quantify rumination time for a finishing beef animal, and to evaluate the effects of corn stalk inclusion rate and particle size on rumination behavior, animal performance, and carcass characteristics. Fifty-one individually fed steers (initial BW = 385 ± 3.6 kg) were utilized to evaluate the effects of corn stalk (CS) particle size and inclusion rate in steam flaked-corn (SFC)-based finishing diets on animal performance and rumination behavior. Corn stalks were passed through a tub grinder equipped with a 7.62 cm screen once (LG-CS), or twice (SG-CS) to achieve different particles sizes. Dietary treatments included: 30% wet corn gluten feed (WCGF) and 5% SG-CS (5SG), 30% WCGF and 5% LG-CS (5LG), and 25% WCGF with 10% SG-CS (10SG). The Penn State Particle Separator was used to separate ingredients and treatment diets, and to estimate physically effective NDF (peNDF). Steers were outfitted with continuous rumination and activity monitoring collars on d 70. Long grind corn stalks contained more (P less than 0.01) peNDF than SG-CS, and the 10SG diet contained more (P = 0.03) peNDF than the 5LG and 5SG diets. Dry matter intake was greatest (P = 0.03) for steers consuming 5LG, and least for steers consuming 10SG with cattle consuming 5SG being intermediate. Carcass-adjusted ADG and G:F was greatest (P less than or equal to 0.03) for steers consuming 5LG and 5SG compared to 10SG. Hot carcass weight tended (P = 0.10) to be greatest for steers consuming 5LG, and least for steers consuming 10SG with 5SG being intermediate. Dressing percent was greater (P = 0.01) for steers consuming 5LG and 5SG than 10SG. Minutes of rumination per day were greatest (P = 0.01) for steers consuming 10SG, followed by 5LG, and lowest for 5SG. Treating SWDGS with CH showed improvement compared to untreated SWDGS in finishing diets. Increasing particle size of roughage may be a means to decrease roughage inclusion rate while maintaining rumination and performance.