Abstract

MARTINEZ AGUILAR, Margarita; GUTIERREZ, Carlos G.; DOMINGUEZ HERNANDEZ, Yesmín María  and  HERNANDEZ CERON, Joel. Estrous response and pregnancy rate in seasonal anoestrous goats treated with progestogens and bovine somatropin. Rev. mex. de cienc. pecuarias [online]. 2011, vol.2, n.2, pp.221-227. ISSN 2448-6698.

The purpose of the present study was to test whether a single dose of long acting bST 5 d before the end of progestin treatment increases estrus response, conception rate and prolificacy in anoestrous goats induced to ovulate. One hundred and nine cross bred adult goats varying in parity (1-5 kiddings) received an intravaginal sponge containing 45 mg of fluorogestone acetate, which remained in place for 12 d. On d 12 of treatment, does received 300 UI of eCG. Five days before sponge withdrawal goats were randomly assigned to two groups: bST group (n =53) received a depot injection of 125 mg sc of bST. The control group (n = 56) did not receive bST. Goats in estrus were mated with males of proven fertility. Treatment with bST increased (P<0.05) the proportion of goats in estrus (bST, 73.5 % vs control, 51.7 %). Conception rate did not differ (P=0.12; bST, 82 % vs control, 65.5 %). Pregnancy rate was higher (P<0.01) in bST (60.3 %) than in control group (33.9 %). Treatment with bST did not increase (P=0.9) the proportion of goats delivering twins (bST, 59 % vs control, 63 %). IGF-I and insulin concentrations were higher (P<0.01) in goats treated with bST than in control. It can be concluded that addition of bovine somatotropin to an ovulation induction treatment in anoestrous goats increases both estrus response and pregnancy rate.

Keywords : bST; Fertility; Anoestrus; Goats.

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