02050naa a2200193 a 450000100080000000500110000800800410001902400280006010000210008824501090010926000090021852014850022765000120171265000170172465300090174170000200175070000170177077300690178720298042017-07-25       2015    bl uuuu     u00u1 u    #d7 a10.1111/rda.12509.2DOI1 aRODRIGUES, W. B.  aReproductive performance and reconception of Nellore cows according to their pure- or cross-bred calves.  c2015  aThe objective of the present research was to evaluate the effect of a calf?s genetic group on the productive and reproductive efficiency of its Nellore dam. Fixed-time artificial insemination was applied to 800 cows using semen extracted from Nellore, Simmental and Angus Red bulls. Four hundred eleven cows calved, producing 119 Nellore, 103 ½Simmental?½Nellore and 189 ½Nellore?½Angus Red calves. The second mating period, which paired Nellore cows with Simmental bulls, was initiated 10 days after parturitions began and lasted for 5 months. Based on the two successive parturitions, the cumulative parturition rate for calving periods of 3, 4 and 5 months was calculated. Although no significant difference was observed for birth weight among the genetic groups, cross-bred calves weighed, on average, 10% more than did pure-bred calves at the age of 205 days. Nellore dams experienced a gestation period that was 7 days longer than did the cross-bred dams, and the former showed a higher parturition rate at 90 and 120 days of the calving season, but not at 150 days (calving rates of 80.6, 76.4 and 76.2% for mothers of Nellore, ½Nellore?½Angus Red and ½Nellore?½Simmental, respectively, p &gt 0.05). At 90 and 120 days, Nellore dams produced more kg of calf per mated dam. In conclusion, in a short breeding season, Nellore dams nursing pure-bred Nellore calves were found to have a higher biological efficiency compared with Nellore dams nursing cross-bred calves.  aNellore  areproduction  aCalf1 aWECHSLER, F. S.1 aNOGUEIRA, E.  tReproduction in Domestic Animalsgv. 50, n. 3, p. 431-436, 2015.