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The effect of parity age and month of calving on milk fat and protein yield fat and protein percent for the five major dairy breeds

Published online by Cambridge University Press:  22 November 2017

H Joanne Bellamy  and
G J T Swanson
H Joanne Bellamy
Affiliation:
Milk Marketing Board Thames Ditton Surrey KT7 OEL
G J T Swanson
Affiliation:
Milk Marketing Board Thames Ditton Surrey KT7 OEL
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Extract

Records oolleoted from National Milk Reoords (NMR) are used by the Milk Marketing Board (MMB) to produoe genetio evaluations for bulls (Improved Contemporary Comparisons), cows (Cow Genetic Indices) and a management index for cows (Cow Production Index). It is Important to eliminate systematic environmental effects such as age at calving, month of calving and parity. The need for such adjustments and the factors involved have been documented by Schmidt and Van Vleck (1974). The purpose of this study was to calculate new adjustment factors for each dairy breed for inclusion In bull and cow evaluations.

Sire identified milk reoords of at least 200 days from cows completing laotations in 1885/8S were seleoted from the NMR data base for Ayrshires (A), Jerseys U) and Guernseys (G). Shorthorn (S) records from 1984 were also selected in order to provide sufficient data for analysis. A 10% sample of records were selected for Friesian/Holsteins (F/H) from 1987. The first five lactations were Included. The analyses were performed upon 16,878 S, 37,668 A, 38,925 J, 26,008 G and 80,445 F/H reoords respectively The data were analysed using a least square analysis of varianoe (Harvey 1977).

Type
Cattle Production and Nutrition
Information
Proceedings of the British Society of Animal Production (1972) , Volume 1989 , March 1989 , pp. 138
Copyright
Copyright © British Society of Animal Production 1989

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References

Harvey, W. R., 1977, Users guide for LSML 76. Mixed model least squares and maximum likelihood computer program”. Ohio State Univ, Columbus.Google Scholar
Keown, J. F. and Everett, E. W., 1985, Age-Month adjustment factors for milk, fat and protein yields in Holstein cattle. J. Dairy Sci. 68 2664–9.Google Scholar
Miller, P.D., Lentz, W. E., and Henderson, C.R., 1970, Joint influence of month and age at calving on milk yield of Holstein oows in the northeastern United States. J. Dairy Soi. 53 351–357.CrossRefGoogle Scholar
Schmidt, Q. H. and Van Vleck, L. D., Correction of records for non-genetic factors.In Principles of Dairy Science. pub. W. H. Freeman and Co, 1974. pp. 209–225.Google Scholar