Relationships of empty-body composition and fat distribution to live animal and carcass measurements in Bos indicus-Bos taurus crossbred cows

Abstract

Empty-body composition and fat distribution were determined for 55 nonpregnant, mature Bos indicus-Bos taurus crossbred cows fed to achieve variation in fatness. Prior to slaughter, cows were condition and frame scored, weighed and measured for hook height, hook width, heart girth and lengths from point of shoulder to pin and hook to pin. Fat thickness at three locations and ribeye area were measured ultrasonically on the live animal and carcass. Quality and yield grades were determined after a 48-h postslaughter chill. Visceral fat was excised at slaughter and weighed. Kidney, heart and pelvic (KHP) fat was excised from one side and the remainder of the side was separated into bone and soft tissue. Soft tissue was subsampled and analyzed for ether extract. Proportions of fat in soft tissue, bone, viscera and KHP were calculated. Variations of percentage of empty-body fat in soft tissue, KHP and bone were explained (R2 greater than .64) by equations involving either live animal or carcass measurements. Both ultrasonic and subjective fat estimates were of importance (P less than .05) in equations predicting fatness, indicating the importance of variation in fat distribution. Factor analysis indicated that fat accretion is a complex entity composed of several distinct distribution patterns (anterior-posterior, internal-external, intramuscular-intermuscular).