Understanding the Effect of Reduced Supplementation Frequency on Performance, Digestion and Metabolism of Stocker Cattle.

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Title: Understanding the Effect of Reduced Supplementation Frequency on Performance, Digestion and Metabolism of Stocker Cattle.
Author: Drewnoski, Mary Elizabeth
Advisors: Gerald Huntington, Committee Co-Chair
Geoff Benson, Committee Member
Matthew Poore, Committee Co-Chair
Vivek Fellnar, Committee Member
Abstract: Supplements are often fed to stocker cattle on forage-based diets to improve animal performance. Delivery costs can make up a substantial portion of the cost of supplementation. Reducing supplementation frequency can reduce labor and equipment costs and therefore has the potential to increase profit. However, less frequent feeding requires feeding larger quantities of supplement at once and can increase the likelihood of negative associative effects of supplementation. Additionally, little is understood about the metabolic response of ruminants to large fluxuation in nutrient intake. A 50:50 blend of soyhulls and corn gluten feed is widely used by producers to supplement growing cattle. This blend is high in energy but low in starch. It also contains a moderate amount of protein, much of which is ruminally degradable. The purpose of this research was to determine the effect of reducing supplementation frequency of a soybean hull and corn gluten feed blend on performance, digestion, and concentrations of metabolites and hormonal growth regulators in blood of steers. In Experiment 1, growing steers consuming medium quality fescue hay were supplemented either daily, 3 times a week, or 2 times a week. Hay intake was decreased by reducing supplementation frequency but gains were not affected. As a result, the feed to gain ratio increased slightly with less frequent supplementation. In Experiment 2, six ruminally cannulated steers consuming medium quality fescue hay were used in a replicated 3 x 3 Latin square to determine the effect of supplement frequency (daily at 1% BW or on alternate days at 2% BW) on digestion and ruminal parameters. Reducing supplementation frequency decreased hay intake but did not affect digestibility of the diet. On the day of supplementation molar proportions both of propionate and butyrate in the rumen of steers supplemented on alternate days was increased compared to those supplemented daily. In Experiment 3, growing steers were individually fed medium quality hay and supplemented daily (1% BW) or on alternate days (2% BW). Gains did not differ due to supplementation frequency. However, plasma IGF-1 was greater and insulin tended to be greater in steers supplemented less frequently.
Date: 2009-08-14
Degree: PhD
Discipline: Nutrition
URI: http://www.lib.ncsu.edu/resolver/1840.16/5273

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