Fertility and survival of Swedish Red and White ? Holstein crossbred cows and purebred Holstein cows

摘要

Swedish Red and White x Holstein (SxH) cows were compared with pure Holstein (HOL) cows for fertil-ity and survival traits in 2 commercial dairy farms in central-southern Cordoba province, Argentina, over 6 years (2008-2013). The following traits were evaluated: first service conception rate (FSCR), overall concep-tion rate (CR), number of services per conception (SC), days open (DO), mortality rate, culling rate, survival to subsequent calvings, and length of productive life (LPL). The data set consisted of 506 lactations from 240 SxH crossbred cows and 1,331 lactations from 576 HOL cows. The FSCR and CR were analyzed using logistic regression, DO and LPL were analyzed using a Cox's proportional hazards regression model, and dif-ferences of proportions were calculated for mortality rate, culling rate, and survival to subsequent calvings. The SxH cows were superior to HOL cows in overall lactations for all the fertility traits (+10.5% FSCR, +7.7% CR, -0.5 SC, and 35 fewer DO). During the first lactation, SxH cows were superior to HOL cows for all fertility traits (+12.8% FSCR, +8.0% CR, -0.4 SC, and 34 fewer DO). In the second lactation, SxH cows exhibited lower SC (-0.5) and 21 fewer DO than HOL cows. In the third or greater lactations, SxH cows showed higher FSCR (+11.0%) and CR (+12.2%), lower SC (-0.8), and 44 fewer DO than pure HOL cows. In addition, SxH cows had a lower mortality rate (-4.7%) and a lower culling rate (-13.7%) than HOL cows. Due to the higher fertility and lower mortality and culling rates, the SxH cows had higher survival to the second (+9.2%), third (+16.9%), and fourth (+18.7%) calvings than HOL cows. Because of these results, SxH cows had longer LPL (+10.3 mo) than HOL cows. These results indicate that SxH cows had higher fertility and survival than HOL cows on com-mercial dairy farms in Argentina.