Masters Theses

Date of Award

8-1990

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Science

Major Professor

John C. Waller

Committee Members

James K. Miller, James D. Quigley III

Abstract

In Experiment 1, calves were fed supplement containing rumen-escape protein (REP) and rumen-escape energy (REE) to determine its effects in starting animals on feed. Sixty steer calves were randomly allotted to 12 feedlot pens (five steers/pen) for a 42-d receiving period. Steers were assigned to three dietary treatments: (1) corn silage, (2) corn silage + Bull Developer (BD), and (3) corn silage + high level of REP and REE (HIGH). Calves were weighed on d 0, 14, 28, and 42. Steers fed the HIGH supplement had significantly higher average daily gain (ADG) than had those receiving corn silage alone but were similar to those consuming BD.

In Experiment 2, calves were fed supplements containing three levels of REP and REE. Trial 1 involved 168 newly weaned steers and heifers (258 kg) allotted to 28 pens (six animals/pen) on the basis of body weight. Supplements consisted of: (1) BD, (2) Low level of REP and REE (LOW), (3) Intermediate level of REP and REE (MED), and (4) High. Supplements were fed along with BD and corn silage for a period of 28 d. Feed intakes were recorded daily and calves were weighed on d 0, 14, and 28. Significant differences in ADG were found only between BD and HIGH in the group of steers. In Trial 2, 72 newly-weaned steers (257 kg) were allotted to 12 pens (six steers/pen) for 28 d. Three treatments (LOW, MED, and HIGH) were randomly assigned to the 12 pens (four pens/treatment). Average daily gain was lower (P<.05) on the MED treatment. In Trial 3, two groups of steers were allotted to 18 feedlot pens. In group 1, 54 steer calves (237 kg) were allotted to nine pens (six steers/pen). In group 2, 81 steer calves (212 kg) were allotted to nine pens (nine steers/pen). Treatments were the same as in Trial 2. Treatment had no significant effect on animal performance.

In Experiment 3, four ruminally-cannulated steers (545 kg) were used to evaluate the four supplements used in Experiment 2. Treatments were assigned in a 4x4 Latin square design. Steers were fed on the basis of d 14 levels of intake from Experiment 2, adjusted for differences in body weight. Steers were fed each treatment for a period of 10 d, with rumen fluid and blood being collected on d 8 and 10. Rumen pH, rumen ammonia (RA), blood urea nitrogen (BUN), and rumen volatile fatty acids (VFA) levels were measured at 2, 4, 6, and 8 h post-feeding. Rumen pH, RA, and BUN were affected by sampling time and period. No differences were detected between treatments.

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