phenotypic study of lactation curve in iranian holsteins
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abstract
a total of 136,250 monthly test day milk records collected from 13,625 iranian holstein heifers (three times a day milking) calved between 1991 and 2001 and distributed over 264 herds were used to study the effects of some environmental factors influencing lacta-tion curve parameters as well as production characteristics. wilmink’s function (yt = w0 + w1t + w2e-0.05t) was fitted to individual lactations. least squares analysis of variance in-dicated that the herd, year and month of calving had a significant effect on all traits under consideration. correlation analysis showed that the parameter w0 had a negative and significant (p
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Journal title:
journal of agricultural science and technologyPublisher: tarbiat modares university
ISSN 1680-7073
volume 9
issue Number 4 2010
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