ABSTRACT We evaluated the reproductive losses in three periods: period I – starting from the time the cows were exposed to the bulls to pregnancy diagnoses (PD, number of cows diagnosed as non-pregnant/total exposed cows × 100); period II – from the time of PD to calving (number of calving cows/number of cows diagnosed as pregnant × 100); and period III – from calving to weaning (number of weaned calves/number of calving cows × 100) in purebred Hereford (HH) and […]

Records of start of breeding season and subsequent calving, from 1,247 Nelore females raised at Sertãozinho Experimental Station (IZ ¾ SP, Brazil), selected for high (selection and traditional lines) and for average (control line) yearling weights were used to compute days to calving and to study the effect of selection for yearling weight on reproductive performance. Data sets of heifers, and cow and heifers were analyzed with and without non-calvers females. There were no significant differences among the performance of […]

The experiment was run at the Agronomic Experimental Station of the Federal University of Rio Grande do Sul, located in the district of Eldorado do Sul, Brazil. The objective of the study was to evaluate the effect of the date of early (01/05/99) or conventional (03/26/99) weaning on the reproductive performance of multiparous beef cows during two mating seasons, 98/99, and the subsequent, 99/00. Fifty cows had their calves weaned with an average age of 91 days old and a […]

The objective of this work was to study birth (BW) and weaning (WW) weights, and birth weight/cow weight at calving (BWR) and weaning weight/cow weight at calving (WWR) ratios of 1/2 Canchim + 1/2 Nellore and 1/2 Charolais + 1/4 Canchim + 1/4 Nellore calves out of straightbred Nellore and crossbred 1/2 Canchim + 1/2 Nellore cows, and sired by Canchim (5/8 Charolais + 3/8 Zebu) and Charolais bulls, respectively. Analyses of variance were carried out separately for each genetic […]