Abstract

AMORIM, E.A.M. et al. Estrous synchronization with recycled CIDR in lactating Toggenburg does treated with recombinant bovine somatotropin (r-bST). Arq. Bras. Med. Vet. Zootec. [online]. 2008, vol.60, n.1, pp. 51-57. ISSN 0102-0935.  http://dx.doi.org/10.1590/S0102-09352008000100008.

The response of goats treated with r-bST in the estrous synchronization protocol was evaluated. Twenty-six Toggenburg females were divided in two treatments: T1 (n=13) treated with four injections of 250mg r-bST, at 14 days intervals, and T2 (n=13) treated with saline solution (control). The intravaginal device previously used by five days was inserted (day 0) one week after the last injection of r-bST and PGF_2a (22.5µg) was injected in the animals of both treatments. The device was removed on day 6. All the females in estrus were bred by fertile bucks. The percentage of animals in estrus and the pregnancy rate were: 76.9 and 70, and 84.6 and 72.7% for goats in T1 and T2, respectively. The estrous cycle length; the interval from treatment to the onset of estrus; the ovulation number; and the intervals from the onset of estrus to ovulation, end of estrus to ovulation, and from device removal to ovulation were not affected by r-bST injection. The r-bST did not affect the diameter of the ovulatory follicles (P>0.05). Progesterone concentration showed similar values (P>0.05) among the goats of T1 and T2 during the treatment with device. The r-bST administration did not affect estrous synchronization.

Keywords : goat; intravaginal device; estrous; pregnancy rate.