Thirty-two weaned Kenana bull calves were adequately fed to maximize growth and serially slaughtered at predetermined live weights of 100, 200, 300 and 400 kg. Eight animals were slaughtered at each slaughter point and the left side of each carcass dissected into individual muscles, bone, fat, tendons and fascia. Individual muscles were grouped into nine muscle groups and the distribution of intermuscular fat was studied in four anatomical regions. Huxley's (1932) allometric equation was used to describe the development of carcass tissues.
Relative to overall carcass side growth, fat was the fastest developing tissue, followed by muscle and bone tissues in descending order. The muscles of neck + thorax and abdominal muscles exhibited the fastest rate of growth relative to overall total side muscle growth, and the distal muscles of both limbs exhibited the slowest rate of relative growth. Relative to the rate of side fat deposition throughout the experiment, subcutaneous fat was deposited at a faster rate than intermuscular or kidney + channel fat. Intermuscular fat was deposited at different rates in the anatomical regions of the carcass.
The development of muscle groups was further examined in three arbitrary phases of the test period and revealed significant differences between phases in the rate at which each muscle group developed. Similar changes in the intensity of the rate at which fat was deposited in the subcutaneous region and between the muscles of the carcass or sites were evident.
Kenana cattle compare favourably with foreign dairy and beef breeds of cattle in muscle:bone ratio. Further studies are needed to evaluate the efficiency of meat production from Kenana cattle under different systems of management.
As reported in Part 1 (Gaili & Nour, 1980) a study was conducted to investigate the development of body components in Kenana cattle and to evaluate the potential of the breed for meat production. This paper is an account of the data which were obtained on the development of carcass tissues.