Description
In order to assess the reproductive effects of Prostaglandin F2alfa (PGF2alfa) administration at the onset or the end of a progestagen treatment in Portuguese Serrana goats, an initial group of 44 females (5 were later rejected for several reasons) aged between 3 and 7 years was used. In May (beginning of the breeding season), all goats were treated with an intravaginal sponge impregnated with 20 mg of fluorogestone acetate (FGA) for 5 days and injected (i.m.) with 300 UI of eCG at sponge removal time. Half goats received an injection (i.m.) of 100 ug of cloprostenol at sponge insertion time (SI) and the other half at sponge removal time (SR). Blood samples were taken for progesterone determination and 4 intact bucks with harness marker were used to identify the estrus. A transrectal ultrasound scanning was performed for pregnancy diagnosis 41 days after eCG administration. PGF2alfa injection at the onset of the FGA treatment had a positive effect in estrus (SI – 100.0% vs. SR – 90.9%; Chi2 = 9.424; P<0.01), ovulation (SI – 100.0% vs. SR – 95.5%; Chi2 = 4.082; P<0.01) and pregnancy (SI – 100.0% vs. SR – 90.9%; Chi2 = 9.424; P<0.01) and fertility (SI – 100.0% vs. SR – 72.7%; Chi2 = 31.214; P<0.001) rates. Time of PGF2alfa injection just had no significant effect in prolificacy (SI – 2.1 ± 0.8 vs. SR – 2.2 ± 0.8; P>0.05). In conclusion, data indicate that PGF2alfa should be administrated at the onset of the FGA treatment.
; Azevedo, Jorge Manuel Teixeira de 
