Productive indicator in a Holstein dairy herd: growth and height curves, reproductive and productive traits and genetic parameters
Val, J.E.; Freitas, M.A.R.; Oliveira, H.N.; Cardoso, V.L.; Machado, P.F.; Paneto, J.C.C.
Arquivo Brasileiro de Medicina Veterinaria e Zootecnia 56(1): 86-93
ISSN/ISBN: 0102-0935 DOI: 10.1590/s0102-09352004000100014
Data on weight, height, productive and reproductive performance of 1,272 Holstein heifers, born front 1990 to 1998, were used to evaluate the growth and height patterns of these females from birth to first calving, and the following traits: weight at first calving (PP), age at first calving (IP), milk production in the first lactation (PL) and first calving interval (IEP), and to estimate genetic parameters of these traits. The von Bertalanffy fitted models were: Yi=802.10 (1-0.630EXP (-0.0022t))for weight, and Yi=1.40 (1-0.208EXP (-0.0038t)) for height. The average performance of heifers were: height 140cm, weight 602kg and 27 month of age atfirst calving. The total milk yield was 8,026kg and first IEP was 420 days. The (co)variance components estimates were obtained by a derivative-free algorithm with the DFREML. The estimates of heritabilities were 0.31, 0.35, 0.34, respectively for PP, IP and PL, and 0,10 for IEP. The genetic correlations estimates between PP and PL, PL and IP and IEP and PL were low. The correlation between IEP and PP was 0.49 and between IEP and IP was, -0.69, sugesting an antagonism between the two last traits.