Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Dan H. Gee


The ultimate goal of the beef industry is efficient production of beef that satisfies the consumer and increases demand. In the past, American producers have been primarily interested in the production of high quality beef because consumers were concerned with meat palatability, particularly tenderness. However, due to current diet-health issues and economic conditions, American consumers have come to expect acceptable palatability and are now more concerned with the nutrient density and cost of their meat purchases. Maximum production efficiency must be realized to keep beef competitive with other protein sources for consumer dollars. Production systems must be used that are capable of producing more lean beef per animal on less feed without sacrificing palatability. Since the ratio between feed costs for gains of fat and muscle is about 7 to 1, the over-fattening of an animal in an effort to obtain more tender meat is no longer economically feasible. Anabolic agents in the form of subcutaneous implants have been used since the early 1950's to increase the production efficiency of slaughter beef cattle. Implants have been developed for steers and heifers that have led to improvements of about 15% in growth rate and about 10% in fed conversion efficiency. Success with these growth-promoting compounds has been shown particularly in intensive rearing situations. One of the greatest immediate opportunities available to the beef industry for reducing production costs is. the producing, feeding and marketing of intact males. Research discussed later indicates intact males grow more rapidly, utilize feed more efficiently and produce a higher yielding carcass (more retail product) with less fat and more muscle than castrates. Although intact males increase production efficiency, considerable resistance in traditional marketing channels has been encountered for beef from young, intact males. Seideman et al. indicated young bulls have a low packer acceptance because of difficult hide removal, heavy carcass weights and low USDA quality grades. The authors also suggested packer unacceptability has been associated with the belief that beef from bulls has lower consumer acceptance at the retail level because of differences in color, texture and fat distribution. In addition, cooked meat from intact males is often less tender than steer beef. In one such study, Forrest concluded no benefits accrue from implanting young bulls with progesterone-estradiol in terms of growth rate, feed efficiency or lean content. The objectives of this study were to determine the effects of implanted anabolic agents on the cutability and quality of carcasses from intact males of two breed groups and to study the sensory traits of beef derived from these intact males.

Library of Congress Subject Headings

Beef cattle -- Carcasses
Beef -- Quality
Anabolic steroids in animal nutrition
Growth factors -- Implantation



Number of Pages



South Dakota State University


No Copyright - United State