U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
Date of this Version
7-1-2021
Document Type
Article
Citation
Transl. Anim. Sci. 2021.5:1-7
doi: 10.1093/tas/txab031
Abstract
The period of heifer development is a relatively small fraction of a cow's life; however, her pattern of growth may have permanent effects on her productivity as a cow. We hypothesized that altering the growth pattern during the peri-pubertal period would increase life-time productivity across genetic types of Bos taurus cows. The objective was to determine the stayability, calf production, and weight of calf weaned across six calf crops. Heifers (n = 685) were placed on one of two developmental programs at 256 ± 1 d of age. Control heifers received a diet that provided 228 kcal ME·(body weight [BW], kg) -0.75 daily, and stair-step heifers were allocated 157 kcal ME·(BW, kg)-0.75 daily for 84 or 85 d, and then the daily allocation was increased to 277 kcal ME·(BW, kg)-0.75. Stair-step heifers (0.33 ± 0.02 kg/d) had a lower average daily gain (ADG) than control heifers (0.78 ± 0.02 kg/d; P < 0.001) during Period 1, and stair-step heifers (0.93 ± 0.03 kg/d) had a greater ADG than controls (0.70 ± 0.03 kg/d; P < 0.001) during Period 2. There were no treatment (P = 0.28) or breed type differences (P = 0.42) for the proportion of cows weaning a calf; however, the proportion of cows weaning a calf decreased with cow age (P < 0.001). Calves from stair-step dams had heavier weaning weights (193 ± 1 kg) compared to control calves (191 ± 1 kg; P = 0.007). There was not a treatment (P = 0.25) or breed type differences in cumulative BW weaned (P = 0.59). A diverse genetic population of cattle within B. taurus was tested and responses in calf production did not differ between stair-step growth pattern and a more constant nonobese growth pattern.
Comments
Published by Oxford University Press on behalf of the American Society of Animal Science 2021. This work is written by (a) US Government employee(s) and is in the public domain in the US.