Effects of pregnancy on daily milk yield of Holstein-Friesian dairy cattle

A - Papers appearing in refereed journals

Brotherstone, S., Thompson, R. and White, I. M. S. 2004. Effects of pregnancy on daily milk yield of Holstein-Friesian dairy cattle. Livestock Production Science. 87 (2-3), pp. 265-269.

AuthorsBrotherstone, S., Thompson, R. and White, I. M. S.
Abstract

First, second and third lactation curves of 21,885 first lactation dairy cows were allowed to vary depending on the months in milk at which the cow became pregnant. The curves were modelled using a 4th degree polynomial of days in milk. In the models for second and third lactation daily yield, days open in the previous lactation was included as a quadratic regression.

Allowing the curve coefficients to depend on the month in milk when pregnancy occurred significantly improved the goodness of fit of the model to the data. The linear and quadratic coefficients of second and third lactation daily milk yield on days open in first and second lactation, respectively, were also significant. We suggest that, in the evaluation of test day milk yield, the shape of lactation curves are allowed to vary depending on the months in milk when pregnancy occurs and that days open in the previous lactation, if appropriate, is included in the model.

KeywordsTest day models; Lactation curves; Cattle pregnancy; Days open
Year of Publication2004
JournalLivestock Production Science
Journal citation87 (2-3), pp. 265-269
Digital Object Identifier (DOI)doi:10.1016/j.livprodsci.2003.07.014
Open accessPublished as non-open access
Funder project or code445
513
Application of non-linear mathematics and stochastic modelling to biological systems
Output statusPublished
Publication dates
Print01 May 2004
Online05 Dec 2003
Publication process dates
Accepted29 Jul 2003
Copyright licensePublisher copyright
PublisherElsevier

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