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A note on the estimation of environmental effects on lactation curves

Published online by Cambridge University Press:  02 September 2010

E. Strandberg  and
C. Lundberg
E. Strandberg
Affiliation:
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, PO Box 7023, S-75007 Uppsala, Sweden
C. Lundberg
Affiliation:
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, PO Box 7023, S-75007 Uppsala, Sweden
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Abstract

A method was suggested that attempts to distinguish between the underlying lactation curve, the effect of season of production, and the effect of time after conception. The composite function was shown to give a better fit than an incomplete gamma function. The estimated parameters of the underlying lactation curve were unaffected by season of calving whereas the parameters of the gamma function were not. Pregnancy started to affect yield 160 days after conception by -0·1 kg/day. The difference between the best season of production (May) and the worst (November) was around 5 kg.

Keywords

dairy cowslactation curvepregnancyseasonality
Type
Notes
Information
Animal Production , Volume 53 , Issue 3 , December 1991 , pp. 399 - 402
Copyright
Copyright © British Society of Animal Science 1991

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