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Relations between first and second lactation characters of progeny groups and effects of tandem selection on yield improvement

Published online by Cambridge University Press:  02 September 2010

Reuven Bar-Anan
Reuven Bar-Anan
Affiliation:
Department of Animal Husbandry, Ministry of Agriculture, Hakirya, Tel-Aviv, Israel
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Summary

Correlations and regressions between estimated breeding values for 122 day part-lactation, 1st and 2nd lactation yield (part, 1st, 2nd) were estimated from 106 sire progeny groups, each with at least 60 effective daughters.

The genetic correlations between part, 1st and 2nd kg milk were 1·0 and 0·84 respectively, and the regressions of 1st on part and of 2nd on 1st test were 2·40 and 0·82 kg/kg milk, respectively. Selection by one standard deviation between sires on part-lactation tests would improve 1st lactation yields by an average of 204 kg milk with a standard deviation of 84 kg. Selection on 1st lactation yields by one standard deviation would increase 2nd lactation yields by an average of 183 kg milk with a standard deviation of 156 kg, indicating that some bulls so selected could have below average 2nd lactation yields.

Two sire selection models were simulated differing in the selection criterion; 1 st yield in model 1, and 1 st followed by 2nd yields in model 2. The contribution of proven sires to the rate of genetic improvement in lifetime production was greater from model 2 than from model 1 by about 15% without any additional costs for bull maintenance.

Type
Research Article
Information
Animal Production , Volume 21 , Issue 2 , October 1975 , pp. 121 - 125
Copyright
Copyright © British Society of Animal Science 1975

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References

REFERENCES

Bar-Anan, R. and Sacks, J. M. 1974. Sire evaluation and estimation of genetic gain in Israeli dairy herds. Anim. Prod. 18: 59–66.Google Scholar
Barker, J. S. F. and Robertson, A. 1966. Genetic and phenotypic parameters for the first three lactations in Friesian cows. Anim. Prod. 8: 221–240.Google Scholar
Fimland, E. A., Bar-Anan, R. and Harvey, W. R. 1972. Studies on dairy records from Israeli-Friesian cattle. Ada Agric. scand. 22: 34–68.CrossRefGoogle Scholar
Grantham, J. A., White, J. M., Vinson, W. E. and Kliewer, R. H. 1974. Genetic relationships between milk production and type in Holsteins. J. Dairy Sci. 57:1483–1488.CrossRefGoogle Scholar
Norman, H. D., McDaniel, B. T. and Dickinson, F. N. 1972. Regression of daughter and herdmate milk yield on genetic value of the herdmates' sires. J. Dairy Sci. 55: 1735–1740.CrossRefGoogle Scholar
Roos, A. 1969. Progeny testing for increase of milk from first to later lactations. Meddelande Svensk Husdjursskötsel No. 27.Google Scholar
Tomaszewski, M. A., McDaniel, B. T., Norman, H. D. and Dickinson, F. N. 1975. Relations between sire summaries of first and second lactations. J. Dairy Sci. 58: 116–121.CrossRefGoogle Scholar
Van Vleck, L. D. and Henderson, C. R. 1963. Bias in sire evaluation due to selection. J. Dairy Sci. 46: 976–982.CrossRefGoogle Scholar