Fat distribution in bulls of different breeds and crosses

Abstract

Cross-sectional data were obtained from a serial slaughter of 197 bulls from a five breed diallel involving Angus, Brahman, Hereford, Holstein and Jersey collected at the Texas A&M Agricultural Research Center at McGregor. The objectives of this study were: (1) to characterize growth patterns for specified fat depots of bulls representing different breedtypes and (2) to determine if differences exist in quantity and site of fat deposition among bulls of different breedtypes slaughtered at various chronological ages. Calves for this research were delivered to the Research Center at approximately three months of age. After an adjustment period two animals from each breedtype were randomly assigned to one of seven slaughter groups: 6, 9, 12, 15, 18, 24 and 30 months. Each bull was assigned to an individual pen and fed a 72% TDN ration ad libitum until time of slaughter. The body composition of these animals was determined by chemical analysis of samples of blood, hide, viscera, lean and bone, subsequent to cutout, weighing, grinding and freeze drying. Chemical fat percentages and carcass dissection data were used to calculate the f a t content in lean, bone, viscera and blood. Estimates from these calculations were used to define four major fat depots: (1) carcass fat (CFAT), (2) viscera fat (VIF), (3) kidney plus (KPF) and (4) blood fat (BLF)..