The efficiency of injectable P4 combined with the male effect on the pregnancy rate of boer goats in the off-season

Goats are seasonally polyestrous, which implies that the kid production is restricted to once a year. However, through estrous cycle manipulation, the production can be distributed throughout the year. Therefore, the present study aimed to estimate the reproductive viability of Boer female goats after administration of injectable P4, either combined with the male effect or independently, during the off-season in the southern region of Paraná. The outcomes evaluated in the study included the pregnancy rate, parturition rate, twin births, number of births, and concentration of births. The study was conducted in a beef goat farm, using 72 goats randomly assigned to three experimental groups. In the G1 group (n=22), females were stimulated by the male effect, in the G2 group (n=25), the animals received 75 mg of P4 intramuscularly at the beginning of the experiment, and in the G3 group (n=25), the goats received 75 mg of P4 intramuscularly at the beginning of the experiment combined with the male effect. The goats were in a breeding season of 60 days. The pregnancy rate, parturition rate, percentage of twin births, and the number of kids born per group were evaluated. The use of injectable P4 showed a similar pregnancy rate to the other groups, with a higher concentration of births in the G1 and G3 groups, both of which were subjected to the male effect (p<0.05). Furthermore, more studies should be carried out using different P4 concentrations.