Taxa de fertilidade de novilhas de diferentes grupos genéticos com primeiro serviço aos 14 meses de idade

Abstract

The aim of this study was to evaluate the reconception rate of heifers of three different genetic groups: Guzerá, ½ Guzerá x ½ Nelore cross and ½ Angus x ½ Nelore cross. Were used 36 primiparous heifers were diagnosed pregnant in the first breeding season, 3 heifers Guzera (G), 9 ½ Guzera ½ Nellore (GN) and 24 ½ Red Angus ½ Nellore (AN), with a mean age of 26 months in the second breeding and weight of 313.67 ± 25.01 kg , 336.50 ± 45.84 kg and 399.86 ± 44.45 kg for females G , GN and AN , respectively race season. All animals were from the same herd and were kept from birth under the same environmental conditions, handling and feeding. Primiparous heifers were kept in six paddocks of 15 ha with Brachiaria brizantha cv. Marandu pasture and all paddocks were provided with water fountain and covered troughs for supplying mineral and / or protein and supplementation. Females remained in each paddock for 14 days in rotational grazing management. The weight of the animals were performed at baseline and every 56 days, together with the assessment of body condition score of each animal. The second breeding season lasted 90 days beginning in January 2013 and end in April of that year and was carried out through natural mating. .Gynecological pregnancy diagnosis was conducted by rectal palpation 60 days after the end of the breeding season. Reconception rate was analyzed by the Chi- square test and the group with higher rates of conception (58.3%), was the half-blood ½ Angus x Nelore (p <0.05), followed by the group Guzera ½ x ½ Nellore (22.2%) and Guzera (0.0%).