Effects of Growth Pattern on Muscle Growth, Nuclei Number, Protein Accretion, and Body Composition in Heifers
beef, compensatory growth, muscle
The effects of compensatory growth on accretion of muscle mass, protein mass, and nuclei number of the supraspinatus and semitendinosus muscles were evaluated using seven serial slaughter groups of Angus x Limousin heifer calves (n = 28, BW 270 2 9.5 kg). Fractional growth rates of carcass protein and fat were also evaluated. To achieve compensatory growth, energy intake was restricted for 88 days (Phase 1) followed by adlibitum feeding of a high energy diet (Phase2) [LH]. Controls were allowed continuous ad libitum access to the high energy diet (HH). Muscle weights, body composition samples, and muscle biopsies were collected at various weight (465 vs 500 kg) or age (88 vs 186 days) constants. Phase 1 energy restriction limited body weight, carcass weight, carcass protein mass, and carcass fat mass (P<.05). This was the result of the limited tissue fractional growth rates. The fractional growth rate of protein for heifers exhibiting compensatory growth was not increased but was maintained until maximum carcass protein mass was attained. Maximum carcass protein mass was attained by a weight of 465 kg. Any further increase in carcass weight was primarily attributed to an increase of carcass fat mass regardless of previous management. Energy restriction limited muscle, protein, and nuclei accretion rates. Heifers exhibiting compensatory growth sustained a linear growth potential until maximum muscle mass occurred at an end point similar to cattle not exhibiting compensatory growth. Muscle nuclei maintained a constant relationship to muscle mass independent of nutritional treatment, muscle type (supraspinatus vs semitendinosus), or days on feed. These data indicate compensatory growth alters the growth curve without affecting the mechanisms of growth.
Number of Pages
South Dakota State University
Copyright © 1993 South Dakota State University.
Alderson, C. L.; Pritchard, R. H.; and Boggs, D. L., "Effects of Growth Pattern on Muscle Growth, Nuclei Number, Protein Accretion, and Body Composition in Heifers" (1993). South Dakota Beef Report, 1993. 18.