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Factors Affecting Pregnancy Rate of Embryo Transfer in Bos indicus and Bos taurus/Bos indicus cows

2006; Taylor & Francis; Volume: 29; Issue: 2 Linguagem: Inglês

10.1080/09712119.2006.9706592

0974-1844

Felipe Montiel, C.S. Galina, I. Rubio, Manuel Corro,

Reproductive Biology and Fertility

Abstract Montiel, F., Galina, C., Rubio, I. and Corro, M. 2006. Factors affecting pregnancy rate of embryo transfer in Bos indicus and Bos taurus/Bos indicus cows. J. Appl. Anim. Res., 29: 149–152. The present study was conducted to determine the factors affecting pregnancy rate after embryo transfer (ET) in cows from the tropics. Zebu (n=105, Experiment I) and Bos taurus/Bos indicus (n=110, Experiment II) potential recipients of embryos were synchronised with a norgestomet implant and received feed supplementation. In both experiments, recipients were divided in two groups: 1) subsequent spontaneous oestrus (SSO) and 2) synchronised oestrus (SO). At ET, recipients of Experiment I (n=50) and II (n=47) were transferred with a single frozen-thawed, in vitro fertilised Fl (Holstein/Zebu) embryo. Pregnancy rate for Experiment I and II was 16% and 36.2%, respectively. In Experiment I, pregnancy rate was affected by day of transfer (day 7 or day 8, P<0.05). In Experiment II, pregnancy rate was affected by oestrus type (SSO and SO), feed supplementation (with and without), and body condition score (low and high; P<0.05).