Document Type

Dissertation - Open Access

Award Date

1978

Degree Name

Doctor of Philosophy (PhD)

Department

Animal Science

First Advisor

L.D. Kamstra

Abstract

A series of three separate experiments were conducted to determine the value of aspen tree (Populus tremuloides Michx.) as a ruminant feed component in growing, finishing and wintering rations. The entire tree, including the branches, leaves and bark, was fed to Hereford steers and commercial bred stock cows. In experiment 1, sixty steers were randomly allotted to six treatments of ten each. The six treatment rations were: 93% alfalfa as control, 12% aspen, 24% aspen, 36% aspen, 48% aspen and 48% aspen (with 4% sodium hydroxide). Soybean meal was included in aspen rations in a ratio of 40% soybean meal to 60% aspen. Aspen and soybean meal combinations then were used to replace 20%, 40%, 60% and 80% of the alfalfa in the control. All rations were pelleted and fed ad libitum. Aspen soybean rations resulted in significantly higher weight gains (except 12% aspen level) and feed efficiency as compared to alfalfa control. TDN was significantly higher for 36% and 48% aspen-soybean rations. Animals graded from standard to good and no differences were observed in tenderness, flavor or juiciness. Aspen steaks from both the growing and finishing phase were rated quite similar by taste panel, both being acceptable with no off flavor. In experiment 2, sixty steers were randomly allotted to six different treatments (10 steers per treatment). The six treatments were: 93% alfalfa, concentrate, concentrate with 15% alfalfa, concentrate with 15% aspen, 48% aspen-32% soybean meal, and 48% aspen-16% soybean meal with 16% chicken manure. Ninety-three percent alfalfa served as control for 48% aspen rations (treatments 5 and 6) while an all concentrate ration (treatment 2) served as control for roughage containing high concentrate rations (treatments 3 and 4). Animals were fed ad libitum to a constant weight of about 500 kg. Treatments 1 and 5 were similar to corresponding treatments in experiment 1, except the rations were fed in the meal form in experiment 2. Roughage addition or type of roughage did not affect the animal performance or appreciably alter the carcass characteristics of concentrate-fed animals. Feedlot performance was poorer for chicken manure-fed animals as compared to those fed the alfalfa ration in experiment 2. Steaks from animals fed the 48% aspen-soybean meal ration had lower cooking losses and were more tender (P<. 05) than those from animals fed alfalfa. In experiment 3, two hundred one pregnant cows were used to demonstrate the use of aspen as a component of wintering rations. Sixty-seven animals each were fed mixed grass hay as control, an aspen-alfalfa pellet (60:40) and an aspen silage (88.5% aspen wood) . Rations were maintained at approximately 7 percent crude protein. Animals received an additional protein supplementation during the last one-third of the gestation period. Animals lost condition (0.2 to 0.7 score units) on all the rations. However, the loss in condition was significantly higher on wood rations. By the end of the trial, the cows had lost 7.4%, 8.8% and 11% of their initial weight on the hay, pellet and wood silage rations, respectively. Normal healthy calves were born in each group with no difference in birth weights or weaning weights between animals fed wood or hay. Aspen wood feeding did not increase the number of open cows the following breeding season. It would appear that aspen wood could serve as a major component in growing and wintering rations and as the roughage component of finishing rations. Aspen must be properly supplemented to correct nutrient deficiencies such as protein, vitamin A and phosphorus. The economic importance of utilizing aspen as a ruminant feed component will depend on several factors especially, the cost of traditional roughages.><.05) than those from animals fed alfalfa. In experiment 3, two hundred one pregnant cows were used to demonstrate the use of aspen as a component of wintering rations. Sixty-seven animals each were fed mixed grass hay as control, an aspen-alfalfa pellet (60:40) and an aspen silage (88.5% aspen wood). Rations were maintained at approximately 7 percent crude protein. Animals received an additional protein supplementation during the last one-third of the gestation period. Animals lost condition (0.2 to 0.7 score units) on all the rations. However, the loss in condition was significantly higher on wood rations. By the end of the trial, the cows had lost 7.4%, 8.8% and 11% of their initial weight on the hay, pellet and wood silage rations, respectively. Normal healthy calves were born in each group with no difference in birth weights or weaning weights between animals fed wood or hay. Aspen wood feeding did not increase the number of open cows the following breeding season. It would appear that aspen wood could serve as a major component in growing and wintering rations and as the roughage component of finishing rations. Aspen must be properly supplemented to correct nutrient deficiencies such as protein, vitamin A and phosphorus. The economic importance of utilizing aspen as a ruminant feed component will depend on several factors especially, the cost of traditional roughages.

Library of Congress Subject Headings

Cattle -- Feeding and feeds
Aspen

Format

application/pdf

Publisher

South Dakota State University

Included in

Beef Science Commons

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