The effect of body-weight loss on the composition of Brahman cross and Africander cross steers: II. Dissected components of the dressed carcass

Abstract

Comparative slaughter was used to assess the effects of body-weight loss on Brahman cross (BX) and Africander cross (AX) steers of the F 3 generation with respect to gross dissected carcass composition and the distribution of these components over the dressed carcass. Animals were slaughtered at design body weights of 325, 341, 358, 374 and 390 kg, some while during positive body-weight growth (Group A), and others during weight loss from 390 kg at a rate of approximately 0-5 kg/day (Group B).Gross composition was similar in the two breeds, irrespective of the body-weight loss treatment. Body-weight loss resulted in muscle and fat approximately reversing the path of development, while bone and fascia and tendon remained approximately constant. No evidence of proportionally early loss of fat and later loss of muscle was found. Of the fat components, kidney and channel fat showed the highest relative loss.The distribution of muscle was different between the breeds, the most statistically significant differences being that AX had heavier muscles around the spinal column and lighter shin muscles, at the same total muscle weight. Bone weight distribution differences also occurred, with AX tending to have lighter leg bones, at the same total bono weight. A breed difference in intermuscular fat distribution meant that the AX animals were earlier developing in the forequarter and later developing in the hind quarter in respect to its intermuscular fat, than the BX animals.Body-weight loss affected muscle-weight distribution, the most marked effect being that the relative proportion of abdominal muscles fell during body-weight loss. Boneweight distribution was affected to a minor extent, the effects mainly being in the leg bones rather than the axial skeleton. The distribution of neither fascia and tendons nor subcutaneous fat was affected by the body-weight loss treatment, but the distribution of intermuscular fat was affected.

Fat distribution in steer carcasses of different breeds and crosses. 2. Distribution between joints

“…The same pattern is suggested by the changes in joint proportions which occur during fattening (Harrington and Pomeroy, 1959;Joubert, 1959;Tayler, Rudman and Kemp, 1961;Luitingh, 1962). Breed differences in fat distribution between joints have been reported by Harte and Conniffe (1967), Kelly, Smith and Bath (1973) and Seebeck (1973). In the first two reports, however, no adjustment was made for differences in the overall level of fatness and it is not clear what effect these had on the results.…”

“…In the first two reports, however, no adjustment was made for differences in the overall level of fatness and it is not clear what effect these had on the results. It has been shown that extreme differences in plane of feeding can alter fat distribution (Seebeck and Tulloh, 1968;Seebeck, 1973).…”

Effects of Breed and Sex on the Relative Growth and Distribution of Bone in Cattle

“…McMeekan (1940) and Richmond and Berg (1972) using pigs, and Seebeck (1973) Seebeck (1913) and Berg et al (1979) indicated that these bones had growth coefficients significantly greater than 1.0 with the lumbar region being the latest maturing in agreement with the growth gradient theory of Hammond (1932). However, Seebeck (1973) and Berg etal. (1979) both failed to separate the ribs from the thoracic and lumbar veretebrae, respectively, and the latter also included part of the pelvic girdle.…”

Iodine nutrition in ewes : effects of low to high iodine intake on iodine content of biological fluids in pregnant and lactating ewes

“…variables determined at each time of sampling, were assessed by analysis of variance with repeated measurements (Winer, 1971). The analysis of variance-covariance was used to describe length of pregnancy and plasma T4 at 16 h postpartum (Seebeck, 1973 (Siegels, 1956 (Fig. 2).…”