Skip to main content Accessibility help
×
Home

Components of environmental variance of yields of cows in different lactations

  • Susan Brotherstone (a1), W. G. Hill (a1) and R. Thompson (a2)

Abstract

With a view to incorporating identifiable environmental factors such as month of calving as random effects in models for dairy sire and cow breeding value estimation, an analysis was undertaken of environmental components of variance for fat yield in lactations 1 to 5 of pedigree British Friesian-Holstein cattle. Records of fat yield and of log fat yield on daughters of widely used sires were first corrected for age and month of calving and for sire in each lactation on a national basis. Variance components for herd-year, herd-year × lactation, herd-year × month of calving, herd-year × month of calving × lactation and error were then estimated for pairs of lactations.

The results were most consistent for log fat yield, where heterogeneity of variance was less. Correlations were, approximately, 0·45 and 0·42 for records in the same herd-year and lactation for lactation 1 or a later lactation, respectively, and approximately 0·40 for records in the same herd-year and different lactations. Within herd-year and lactation, correlations of records in the same month were approximately 0·10 for lactation 1 and 0·08 for later lactations, and for different lactations the correlations were 0·06 if lactation 1 was included and 0·08 otherwise. Thus, the effects appear to be similar for later lactations, which can be pooled, but effects for month and month × lactation 1 v. later should be fitted.

Copyright

References

Hide All
Brotherstone, S. and Hill, W. G. 1986. Heterogeneity of variance amongst herds for milk production. Animal Production 42: 297303.
Chauhan, V. P. S. 1987a. Partitioning of herd, year and season variation in milk production. Livestock Production Science 16: 107116.
Chauhan, V. P. S. 1987b. Dairy sire evaluation fitting some of the herd-year-season effects as random. Livestock Production Science 16: 117130.
Chauhan, V. P. S. and Thompson, R. 1986. Dairy sire evaluation using a “rolling months” model. Journal of Animal Breeding and Genetics 103: 321333.
Harvey, W. R. 1977. Users guide for LSML 76 mixed model least-squares and maximum likelihood computer program. Ohio State University, Columbus. (Mimeograph).
Henderson, C. R. 1975. Best linear unbiased estimation and prediction under a selection model. Biometrics 31: 423447.
Hill, W. G. and Swanson, G. J. T. 1983. A selection index for dairy cows. Animal Production 37: 313319.
Meyer, K. 1987. Estimates of variances due to sire × herd interactions and environmental covariances between paternal half-sibs for first lactation dairy production. Livestock Production Science 17: 95115.
Milk Marketing Board. 1979. The improved contemporary comparison. Report of the Breeding and Production Organisation, Milk Marketing Board, No. 29, pp. 9195.
Milk Marketing Board. 1982. Cow genetic index. Report of the Breeding and Production Organisation, Milk Marketing Board, No. 32, pp. 5966.
Quaas, R. L., Everett, R. W. and McClintock, A. C. 1979. Maternal grandsire model for dairy sire evaluation. Journal of Dairy Science 62: 16481654.
Quaas, R. L. and Pollak, E. J. 1981. Modified equations for sire models with groups. Journal of Dairy Science 64: 18681872.
Thompson, R. 1982. Methods of estimation of genetic parameters. Proceedings of the 2nd World Congress on Genetics Applied to Livestock Production, Madrid, Vol. 5, pp. 95103.

Related content

Powered by UNSILO

Components of environmental variance of yields of cows in different lactations

  • Susan Brotherstone (a1), W. G. Hill (a1) and R. Thompson (a2)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.