Effects of intravaginal administration of prostaglandin F_2α on luteolysis and subsequent estrus in Shiba goats (Capra hircus)

Abstract

This study examined the effects of intravaginal administration of prostaglandin F2α (PGF2α) on luteolysis and subsequent estrus in cycling goats. Goats with functional corpus lutea received one of five treatments: 2 mg of PG intramuscularly (IM2 × 1; n = 6), 2 mg of PGF2α intravaginally (IVG2 × 1; n = 7), 4 mg of PGF2α intravaginally (IVG4 × 1; n = 7), and 1 or 2 mg of PGF2α intravaginally 8 h apart (IVG1 × 2 group; n = 6 and IVG2 × 2; n = 8). Blood samples were collected at 24‐h intervals from 0 to 7 days after PGF2α administration. Estrus was checked twice daily during the experiment. The proportion of goats with complete luteolysis (reduction of progesterone concentrations to <1 ng/mL until 48 h after treatment) in the IVG2 × 1 group (28.6%) was significantly lower than in the other groups (IM2 × 1; 100%, IVG4 × 1; 57.1%, IVG1 × 2; 87.5%, IVG2 × 2; 100%, respectively). For goats completing luteolysis, there was no significant difference in the onset and duration of estrus among the groups. These results suggest that intravaginal administration of PGF2α can be applied as an alternative to intramuscular administration.