Índices de selección en ganado braunvieh en méxico usando metodología de ganancia deseada

Selection indexes were developed for productive and reproductive characteristics of Braunvieh cattle in México, through the desired gain procedure. The data for this study were obtained from the Mexican Braunvieh Cattle Association. Records from 21,547 animals born in 86 herds, offspring of 632 studs and 10,976 cows during 1979 to 2010, were used. The characteristics studied were weight at birth (PN), weight at weaning (PD), weight after one year (PA), age at first labor (EPP), and interval between labors (IEP). Five selection indexes that included 3, 4 or 5 characteristics simultaneously were constructed. The coefficients of the indexes (b) were calculated based on the Yamada methodology, such as b(G’ R)1 Q; where: Gnm is the matrix of genetic variances-covariances of the characteristics used as selection criteria (X) and selection objectives (Q); where: Qm1 is the vector of desired genetic changes for the m characteristics; Rnn is the diagonal matrix of the Wright kinship coefficients. The genetic gain per generation for the i-th characteristic was calculated as: GiiI Cov (Gi, I)/ I; where: iIindex intensity; Cov (Gi, I)covariance of the genetic value of the characteristic and index; I(b’Pb)1/2standard deviation of the index; and Pnn matrix of phenotypic variances-covariances. Based on the responses expected and the number of generations necessary to achieve the gains desired, the best indexes were I2 and I4.