Calving records (n = 6,763) obtained from first, second, and third parities of 3,442 spring-calving, Uruguayan Aberdeen Angus cows were used to estimate heritabilities and genetic correlations for the linear trait calving day (CD) and the binary trait calving success (CS), using models that considered CD and CS at 3 calving opportunities as separate traits. Three approaches were defined to hand...

this study was performed to determine the effect of injecting selenium into pregnant heifers at the last stage of gestation on the serum se, cu, zn and fe status of the heifers and their calves. fifty holstein heifers were randomly assigned to one of five treatments. four and two weeks before the expected time of calving, the heifers were injected intramuscularly 10 ml (t1), 20 ml (t2), 30 ml (...

The successful genetic selection for higher milk production caused a dramatic decline in the reproductive performance of dairy cows all over the world during the last decades. Achievement of optimum herd reproductive performance (calving interval of 12 or 13 months with the first calf born at 24 months of age) requires concentrated management activities especially during the first 100 days foll...