Estudio de las pérdidas reproductivas en la cría en campo natural

In the present work, the reproductive losses in the stages corresponding to pregnancy, calving and weaning are described through their indicators (% of pregnancy, % of calving and % of weaning), of the breeding herds of the experimental station of the Faculty of Agronomy EEBR. For this season the system is full cycle breeding in the natural field and using different genotypes (HH, AA, and their crosses) for both cows and bulls. Records of 12 years (1994-2006) were used with a total number of 1106 cows and 83 bulls. Evaluating reproductive losses, the study reveals that on average during the series of years evaluated the highest percentages of losses occurred in pregnancy and weaning, being on average 12.67% and 10.56% respectively and higher in crosses than in pure. When the experimental herds were compared with the DIEA data, it could be observed that for pregnancy the losses are significantly lower than in the commercial rodeos provided by the DIEA. On the other hand, for childbirth and weaning, the losses in these stages are similar to those provided by the bibliographic data in similar studies. As for the bulls, the ones that produced the highest percentages of loss were the HA bulls for the pregnancy and weaning stage and the AH bulls in the pregnancy stage.