The effect of a depot injection of recombinant bovine somatotropin on follicular development and embryo yield in superovulated Holstein heifers

Superovulatory response and embryo quality of Holstein heifers treated with one or two injections of somatotropin

“…In fact, the number of transferable embryos in rbST-I and -II treatments was lower than those reported by Kuehner et al (1993) and Herrier et al (1994) in which only one injection of rbST was administered. The number of transferable embryos produced by donor heifers in our study was far from what we expected from the superstimulation treatment and much lower than that found in other studies without rbST administration and using sexed semen (Sartori et al, 2004;Hayakawa et al, 2009;Peippo et al, 2009).…”

“…However, the mean number of CL (9.3 ± 1.1 vs 9.5 ± 1.5 for rbST-I and rbST-II, respectively) was lower than that reported by Gong et al (1993b) and Kuehner et al (1993) in heifers, and by Herrier et al (1994) in cows when rbST (320 to 640 mg/animal) was administered five days before or at the beginning of the superstimulation. These findings led us to assume that the superstimulation protocol used in our study is reliable for inducing positive SR in donor heifers.…”

“…After administering a single injection seven (Kuehner et al, 1993) or four (Neves et al, 2005) days before and three days after (Márquez-Hernández, 2011) the beginning of the superstimulatory treatment, rbST improved embryo quality. However, donors given rbST five days before commencing (Gong et al, 1993b) or at the beginning (Kuehner et al, 1993) of the superstimulatory treatment showed an increase in the superovulatory response but not in embryo quality.…”

“…After administering a single injection seven (Kuehner et al, 1993) or four (Neves et al, 2005) days before and three days after (Márquez-Hernández, 2011) the beginning of the superstimulatory treatment, rbST improved embryo quality. However, donors given rbST five days before commencing (Gong et al, 1993b) or at the beginning (Kuehner et al, 1993) of the superstimulatory treatment showed an increase in the superovulatory response but not in embryo quality. We hypothesized that superovulatory response as well as the number of good quality embryos can be increased by the administration of two injections of rbST: the first to increase superovulatory response and, consequently, have a larger number of small follicles recruited before initiating the superstimulatory treatment, and the second to further support growth of the recruited follicles and improve embryo quality.…”

Impactos do uso da somatotropina bovina recombinante (rbST) sobre a reprodução de ruminantes*

“…268, Art. 1787, Outubro, 2014 Doadoras tratadas com rbST no dia 11 e no dia 4 do protocolo de superovulação apresentaram aumento no número de corpos lúteos em relação ao controle e significante aumento na porcentagem de embriões transferíveis (Kuehner et al, 1993).…”