نتایج جستجو برای: age at first calving
تعداد نتایج: 4943216 فیلتر نتایج به سال:
Associations between rearing conditions and the risk of culling in dairy cows were studied by survival analysis. Data were collected from 1039 Swedish Red cows, 1029 Swedish Holsteins, and 56 cows of other milk or cross-breeds, representing all female animals born in 109 Swedish herds during 1998. Length of productive life was defined as the number of days from 1st calving to culling. The appli...
abstract in this thesis at first we comput the determinant of hankel matrix with enteries a_k (x)=?_(m=0)^k??((2k+2-m)¦(k-m)) x^m ? by using a new operator, ? and by writing and solving differential equation of order two at points x=2 and x=-2 . also we show that this determinant under k-binomial transformation is invariant.
In structural equation modeling, it is possible to create hidden variables that cannot be directly measured by the researcher. The aim of this study was to model the structural equations of hidden genetic constructs of production, reproduction and longevity of Holstein dairy cows in Iran using breeding value of the traits that make up these constructs. Accordingly, the breeding value of th...
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