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The effect of various sampling intervals on the estimation of lactation milk yield and composition

Published online by Cambridge University Press:  01 June 2009

L. K. O'Connor  and
S. Lipton
L. K. O'Connor
Affiliation:
Milk Marketing Board, Thames Ditton, Surrey
S. Lipton
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts
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Summary

A study was made of the effect of various sampling intervals on the accuracy of estimating lactation milk yield, fat yield, solids-not-fat (S.N.F) yield, fat percentage and S.N.F. percentage. The basic data consisited of daily milk, fat and S.N.F. yields for eighteen lactations made by twelve Dairy Shorthorn cows. Estimates of the lactation yields and quality were obtained using sampling intervals of 7, 14, 28, 42, 56 and 63 days, and were expressed as differences from the actual values. Only in the case of milk yield was there any effective bias in the estimates. This bias increased with increasing sampling interval.

The distributions of differences between estimated and actual values are presented. The error of estimation increased with increasing sampling interval. Keeping in mind the comparatively small-sized sample used in the investigation, the results are discussed in the light of the purposes for which records are kept.

Type
Original Articles
Information
Journal of Dairy Research , Volume 27 , Issue 3 , October 1960 , pp. 389 - 398
Copyright
Copyright © Proprietors of Journal of Dairy Research 1960

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References

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