Effects of Type and Breed of British, Zebu and Dairy Cattle on Production, Palatability and Composition. I. Rate of Gain, Feed Efficiency and Factors Affecting Market Value2

Abstract

University o] Tennessee and U. S. Department o] Agriculture S TEERS varying widely in conformation and type were used in this investigation to determine the advisability of finishing various breeds for market. Feeders and packers may prefer a particular breed or type, but the breed or type most profitable for them may not please consumers. Despite market differentials and ideas of desirable beef conformation, the differences among types and/or breeds, production characteristics and carcass merit have received inadequate study. This is particularly true of studies involving more than two types or breeds fed under similar environmental conditions. Experimental Procedure One hundred and fifty-four steers of six breeds and one cross representing three types (British, Zebu and dairy) were fed during a 5-year period. The distribution by breed and year of birth is given in table 1. Herefords and Angus were secured from station and breeders' herds. Steers containing Zebu breeding were purchased from breeders in Florida and Tennessee. Brahman-cross steers were progeny of Hereford or Angus cows mated to Brahman bulls. Holsteins and Jerseys were obtained from local markets the first 2 years and from the Knoxville and Lewisburg Stations the remaining years. The average on-feed age of all steers was approximately 5 mo., ranging from 3 to 8 mo. All breeds were fed the same ration within years. Minor variations were made among years. Two feeding methods were used. Steers born during 1956 were individually fed in stanchions. Those born during 1957 were fed in breed groups during the early months of the feeding period and then were individually fed until slaughtered. During the remaining 3 yr., all were fed in breed groups. Each steer was slaughtered when it reached an off-feed weight of approximately 900 lb. or an age of approximately 20 mo., whichever was reached first. All were graded when taken off feed by a committee of Animal Husbandry Department staff members. Each steer was given a rigid 24-hr. pre-slaughter shrink with access to neither feed nor water. During this period, each was trucked the 10 mi. distance to the meat laboratory for slaughter. Carcasses were chilled for 48 hr. and graded by a Federal grader who also gave a subjective marbling score. Carcass measurements were taken as outlined by Naumann (1951). Since subclass numbers were unequal and all breeds were not fed every year, data were analyzed by the method of least squares. Constants were fitted for birth year, type and breed within type for the characteristics studied. Analysis of variance tests of significance were made for the above-mentioned sources of variation. Duncan's (1955) multiple range test, as extended by Kramer (1957), was used to test the significance of differences between means within subclasses. Results and Discussion Significant year effects were observed for 21 of the 23 production and carcass characteristics which were statistically analyzed. Only cooler shrink and carcass length did not vary significantly (P > .05) among years. Year differences may be due, in part, to differing sources of steers and to feeding method variations explained earlier. Production Traits, Least square means and Duncan's multiple range test for production traits are given in table 2 by birth year, type 702