Algebraic models of the lactation curves for milk, fat and protein production, with estimates of seasonal variation
Autor: | P. D. P. Wood |
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Rok vydání: | 1976 |
Předmět: | |
Zdroj: | Animal Science. 22:35-40 |
ISSN: | 1748-748X 1357-7298 0003-3561 |
Popis: | SummaryThe lactation curves of whole milk production and of compositional quality measures may be represented by one of a family of curveswhere the coefficients a, b and c define the curve of production of a character y at week n.An analysis of protein results from over 600 000 cows, and of fat results from nearly 3000 cows gave shape coefficients (b, c) for fat percentage (-0·1316, 0·0154) and for protein percentage (-0·1223, 0·0109) showing that the lowest percentage of each occurred during weeks 8 and 11 of lactation respectively.Seasonal variations were calculated to show an expected deficiency of 0·93% fat in the spring and 0·75% protein in winter, which could be attributed to environmental influences associated with varying feeding standards. |
Databáze: | OpenAIRE |
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