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Journal of Dairy Science Vol. 75 No. 5 1273-1280
© 1992 by American Dairy Science Association ®
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Evaluation of Various Measures of and Factors Influencing Feed Efficiency of Dairy Cattle

S. Wang 1, G. L. Roy 2, A. J. Lee 3, A. J. McAllister 3, T. R. Batra 3, C. Y. Lin 3, J. A. Vesely 4, J.-M. Wauthy 5, and K. A. Winter 6

1 Département de Zootechnie, Université Laval, Québec, PQ, Canada G1K 7P4
2 Lennoxville Research Station, Lennoxville, PQ, Canada J1M 1Z3
3 Animal Research Centre, Ottawa, ON, Canada K1A 0C6
4 Lethbridge Research Station, Lethbridge, AB, Canada T1J 4B1
5 Normandin Experimental Farm, Normandin, PQ, Canada G0W 2E0
6 Charlottetown Research Station, Charlottetown, PI, Canada C1A 7M8

Early part records for milk yield and feed consumption of 2230 first lactation purebred and crossbred dairy cows were analyzed to evaluate various measures of feed efficiency. Corrected milk yield was estimated by adjusting the second 8 wk of milk yield for differences in weight of TDN consumed during wk 9 to 16, percentage of TDN derived from concentrate, and BW·75. Corrected milk yield is an estimate assuming that cows are the same size and consume the same amount of feed. Hence, it represents an expression of feed efficiency. Net feed efficiency, gross efficiency, corrected milk yield, and wk 9 to 16 milk were analyzed simultaneously. Coefficient of determination for net efficiency (.51) and gross efficiency (.72) were lower than that of milk (.82), whereas corrected milk yield had a coefficient of determination similar to that of milk. Hence, the use of ratios to define feed efficiency was less accurate than using corrected milk yield Effects of genetic groups, stations, season of freshening, year of freshening, and heterosis were similar for gross efficiency and corrected milk yield, but different from those for milk. Therefore, corrected milk yield performed the same function as feed efficiency with higher accuracy.

Key Words: corrected milk yield • feed efficiency • milk yield

Submitted on July 1, 1991
Accepted on December 16, 1991




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J. S. Britt, R. C. Thomas, N. C. Speer, and M. B. Hall
Efficiency of Converting Nutrient Dry Matter to Milk in Holstein Herds
J Dairy Sci, November 1, 2003; 86(11): 3796 - 3801.
[Abstract] [Full Text] [PDF]


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Copyright © 1992 by the American Dairy Science Association ®.