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Designing beef feedlot nutrition programs to solve environmental challenges related to nitrogen and phosphorus

Galen E Erickson, University of Nebraska - Lincoln

Abstract

Nutrient management issues are continuing to become more important to beef producers and consumers. Nitrogen volatilization is a considerable problem facing the feeding industry and nutritional programs may play a role in solving these important concerns. One area of focus is related to increasing the carbon to nitrogen (C:N) ratio of feedlot manure at the point of excretion to “trap” more nitrogen in manure and thereby decrease volatilization. The approach we studied was to increase organic matter (OM), i.e. carbon, excretion by feedlot steers by either increasing dietary corn silage or corn bran. Both corn silage and corn bran are less digestible than corn and therefore increase OM excretion when fed to feedlot steers. Three experiments were conducted with diets containing either 15 (conventional), 30, or 45% corn silage. Three experiments were also conducted evaluating either 0, 15, or 30% corn bran in the same 15% corn silage diet fed previously. Based on digestibility trials, corn bran was less digestible than corn it replaced. As a result, N volatilization from pens was decreased by feeding more dietary bran. The improvement in volatilization was for winter/spring feeding periods only. Cattle fed higher bran during the summer did not increase N trapped in manure. Corn silage was not effective in trapping N in manure and lowering N losses from open-dirt feedlot pens. Performance was depressed by feeding higher levels of both corn bran and corn silage. ^ Phosphorus is another nutrient that is environmentally challenged. Based on previous research, P requirements of the animal are not well elucidated. Therefore, we conducted a P requirement study using .16, .22, .28, .34, and .40% P in diets fed to finishing calves. Contrary to industry perspective, calves in this study did not require more than .16% P. Performance and bone characteristics were similar across all P levels on the diet. Therefore, we can formulate diets without supplemental P for feedlot calves because of low requirements as well as the large amount of P contributed from corn. If nutritionists formulate diets without supplemental P, then the challenges in managing P for feedlots will be diminished. ^

Subject Area

Biology, Animal Physiology|Agriculture, Animal Culture and Nutrition

Recommended Citation

Erickson, Galen E, "Designing beef feedlot nutrition programs to solve environmental challenges related to nitrogen and phosphorus" (2001). ETD collection for University of Nebraska - Lincoln. AAI3022626.
http://digitalcommons.unl.edu/dissertations/AAI3022626

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