The effects of feeding high-oil corn or typical corn with or without supplemental fat on the digestion, performance, and carcass characteristics of finishing steers
Date
1999
Authors
Belknap, Craig Russell
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Trenkle, Allen H.
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Abstract
The objectives of these experiments were to compare the effects on nutrient digestion, feedlot performance, and carcass merit of steers fed diets containing high-oil corn (HOC), isogenetic typical-corn (TC), or isogenetic typical-corn with animal/vegetable fat (TC+F). Experiment one consisted of two 3 x 3 latin squares utilized in an 84-day digestion trial with ruminally- and duodenally-cannulated steers. Diets consisted of 73-78% whole corn grain, 12.3% corn silage and 2.0% N, with treatment differences being HOC-,TC-, or TC+F-based diets. The HOC and TC+F diets were formulated to provide the same EE content. Total tract (TT) DM (P=.08), OM (P=.08) and N (P=.06) digestibilities tended to be greater for TC than HOC, while starch, NDF, ADF, and EE digestibilities were similar (P>.1O). There were no differences (P>.10) in TT DM, OM, starch, NDF, ADF, EE, or N digestibilities between TC+F and HOC or TC and TC+F. Rumen digestion of DM, OM, starch, NDF, ADF, and feed N was similar (P>.10) among treatments. Microbial-N flow and efficiencies were also similar (P>.10) among treatments. Experiment two consisted of a 107-day feeding trial utilizing ninety yearling crossbred steers fed treatment diets similar to above. No differences in DMI, ADG, or gain/feed were observed (P>.10). Steers fed TC+F yielded carcasses with more BF (P=.04) and a higher calculated YG (P=.01), and tended to yield carcasses with a smaller REA (P=.07), a higher called YG (P=.09), more marbling (P=.09), and a higher %Choice (P=.08) than steers fed TC, while %KPH was similar (P>.10).
Steers fed TC+F also tended to have more BF than steers fed HOC (P=.07), but were similar for %KPH, REA, calculated YG, called YG, marbling, and %Choice (P>.10). Steers fed HOC had a higher %KPH (P=.03) and calculated YG (P=.05), a smaller REA (P=.05), and tended to have higher called YG's (P=.09) than steers fed TC, while BF, marbling, and %Choice was similar (P>. 1O). Results indicate finishing diets composed of primarily HOC to have equal or less feeding value than similar diets composed of TC, and that adding fat to TC diets does not affect its feeding value when fed to finishing steers.
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