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A partial adjustment model to describe the lactation curve of a dairy cow

Published online by Cambridge University Press:  02 September 2010

M. S. Dhanoa  and
Y. L. P. Le Du
M. S. Dhanoa
Affiliation:
Grassland Research Institute, Hurley, Maidenhead, Berkshire SL6 SLR
Y. L. P. Le Du
Affiliation:
Grassland Research Institute, Hurley, Maidenhead, Berkshire SL6 SLR
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Abstract

A new model is proposed to describe the lactation curve of a dairy cow. It uses the fact that milk yield at a given stage of lactation is largely determined by the yield in the preceding stage. The model is written as: yt = λ(m0 – m1t) + (1 – λ)yt–1. t ≥ 1, 0 ≤ λ ≤ 1, where y1, and yt–1 are the current and preceding milk yields in kg/week, and the constant × estimates the fraction (1–λ) by which milk yield adjusts to the level at the next stage. The fraction (1–λ) by which the milk yield persists at the preceding level is used to define a measure of persistency, P = (1–λ)m0/m1 weeks, where m1 is the rate of decline in kg/week and m0 is a constant.

Type
Research Article
Information
Animal Production , Volume 34 , Issue 3 , June 1982 , pp. 243 - 247
Copyright
Copyright © British Society of Animal Science 1982

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References

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