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Analyses of some factors which affect the productivity of beef cows and of their calves in a marginal rainfall area of Rhodesia. 1. Factors affecting calving rate

Published online by Cambridge University Press:  02 September 2010

F. D. Richardson ,
J. Oliver  and
G. P. Y. Clarke
F. D. Richardson
Affiliation:
Mlezu Rural Technical Institute, PO Box 311, Que Que, Rhodesia
J. Oliver
Affiliation:
Department of Agriculture, University of Rhodesia, PO Box MP 167, Mount Pleasant, Salisbury, Rhodesia
G. P. Y. Clarke
Affiliation:
Department of Agriculture, University of Rhodesia, PO Box MP 167, Mount Pleasant, Salisbury, Rhodesia
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Summary

The productivity of cows grazing on veld was studied over four breeding seasons. Different amounts of concentrates were given to three groups of cows during winter and up to 8 weeks post partum. Half of the cows in each group had their calves weaned early (150 days) and the others at the normal time (240 days). Cows given concentrates produced more calves than those given none but time of weaning had no consistent effect on successful conception rates (as judged by subsequent calving rate).

Probit analyses were used to determine the relationship between seasonal body-weight change in the cow and the probability of successful conception. The estimated percentage body-weight changes from autumn peak to mean body weight at the beginning and end of the mating season, which would be followed by successful conception rates of 50%, 75% and 90%, were −14%, −6% and +1% of autumn body weight, respectively.

The practical implications of these results are discussed.

Type
Research Article
Information
Animal Production , Volume 21 , Issue 1 , August 1975 , pp. 41 - 49
Copyright
Copyright © British Society of Animal Science 1975

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References

REFERENCES

Bauer, M. 1965. Five years study of ranch breeding stock. Shod, agric. J. 62: 28–33.Google Scholar
Bembridge, T. J. 1963. Protein supplementary feeding of breeding stock proves profitable under watershed ranching conditions. Shod, agric. J. 60: 98–100.Google Scholar
Bembridge, T. J. 1970. Influence of two levels of supplementary feeding and three stocking rates on the lifetime performance of beef cows. Rhod. agric. J. 67: 139–143.Google Scholar
Elliott, R. C. 1964. Some nutritional factors influencing the productivity of beef cattle in Southern Rhodesia with particular reference to the effect of seasonal changes in the composition of veld, the provision of nutritional supplements to veld grazing and observations on maintenance protein requirements of two breeds of African cattle. Ph.D. Thesis, University of London.Google Scholar
Elliott, R. C. and Fokkema, K. 1961. Herbage consumption studies on beef cattle. 1. Intake studies on Africander and Mashona cows on veld grazing—1958/9. Rhod. agric. J. 58: 49–57.Google Scholar
Finney, D. J. 1971. Probit Analysis. 3rd ed. pp. 50–80. Cambridge University Press, London.Google Scholar
Lamond, D. R. 1970. The influence of undernutrition on reproduction in the cow. Anim. Breed. Abstr. 38: 359–372.Google Scholar
Oliver, J. 1966. The origin, environment and description of the Mashona cattle of Rhodepia. Expl. Agric. 2: 81–88.Google Scholar
Parsons, S. D., Hunter, G. L. and Rayner, A. A. 1967. Use of probit analysis in a study of the effect of the ram on time of ovulation in the ewe. J. Reprod. Fert. 14: 71–80.CrossRefGoogle Scholar
Plowes, D. 1957. The seasonal variation of crude protein in twenty common veld grasses at Matopos, Southern Rhodesia, and related observations. Rhod. agric. J. 54: 33–55.Google Scholar
Pope, L. S. 1967. Winter feeding and reproduction in cows. In Factors Affecting Calf Crop. ed. Cunha, T. J., Warnick, A. C. and Koger, M., pp. 32–43. University of Florida Press, Gainesville.Google Scholar
Vorster, T. H. 1964. Factors influencing the growth, production and reproduction of different breeds of beef cattle under range conditions in Southern Rhodesia. Res. Bull. S. Rhod. Dept. Agric, No. 1.Google Scholar
Ward, H. K. 1968. Supplementation of beef cows grazing on veld. Rhod. J. agric. Res. 6: 93–101.Google Scholar