Effects of Restricted Intake of Growing and Finishing Steers on Feedlot Performance and Carcass Merit

A series of experiments were conducted to evaluate the effects of feeding high concentrate diets at restricted levels on site and extent of digestion, growth performance in the growing and finishing feeding phases, and carcass composition. Five ruminally and duodenally cannulated Angus x Simmental steers were used in a 5 x 5 Latin square design to evaluate the effects of restricting intake of finishing diets containing wheat middlings on site and extent of digestion. Level of intake had no effect on apparent or true rumen digestion of DM or OM. Feeding ad libitum hay resulted in 32.5, 33.4, and 36.9% decreases in DM, OM, and nitrogen digestibilities, respectively, when compared to feeding a finishing diet containing wheat middlings at 75% of ad libitum intake. Microbial DM and OM flows to the small intestine were similar for steers fed the concentrate diets; however, flows were lower for the alfalfa hay diet when compared to the restricted diet containing wheat middlings. Three feedlot performance studies were conducted to evaluate the effects of feeding high concentrate diets containing wheat middlings ad libitum and at restricted levels versus ad libitum intake of alfalfa hay during the growing phase. Restricting intake of a high concentrate diet in the growing phase resulted in decreased daily gains in the growing phase; however, performance in the finishing phase was not affected. Feeding a high concentrate diet, either at ad libitum or restricted intake, resulted in higher daily gains and feed efficiencies during the growing phase when compared to ad libitum hay. Diet in the growing phase showed no effect on carcass quality. Three hundred and eighty-four yearling crossbred steers (368 +/- 23.1 kg) were used to compare DM intake level, implant strategy, and subcutaneous fat endpoint. Restricting intake 10% reduced steer daily gains by 13.1%. Implanting resulted in 19.7% faster daily gains and a 14.3% improvement in feed efficiency. When steers were fed to 1.4 cm backfat, gain:feed ratios were decreased when compared to steers fed to 1.0 cm backfat. Restricted intakes and implantation resulted in a decrease in percentage of steers grading Choice or better.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Animal Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Hermesmeyer, Gregory Neil

Contributors dc:contributor

• Berger, Larry L.

• Agriculture, Animal Culture and Nutrition

Language dc:language

eng

Identifier

(MiAaPQ)AAI9953043

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/83659