Regulação comportamental em caititus (Pecari tajacu): o efeito da estrutura social na função reprodutiva de fêmeas em cativeiro

Abstract

The failure in the fertility of adult female collared peccary (Pecari tajacu) bred in captivity are a restrictive factor for the efficiency of production and needs further investigation. Assess the reproductive function of females reared under intensive rearing system was the objective of this research. Twenty females were monitored in family groups (controls) for 60 days, and experimental groups (female descendants grouped with unrelated males and in the absence of parents), for more 60 days. The agonistic interactions, submission, friendly and sex were recorded three times a week, social dominance was assessed by Elo-rating method and the social preference by frequency of friendly interactions. Blood was collected for measurement of plasma progesterone by solid phase radioimmunoassay and pregnancy was confirmed by ultrasound examination. In three of the four control groups, the parents remained in the highest positions in the hierarchy while in the experimental group stage, the female descendants occupied the highest posts. The frequency of received friendly interactions depended on the sex and the condition (H = 142 991 p <0.01) whereas females mothers received, on average, 2.21 times more interactions than other individuals. Males and females received equal frequencies in the experimental groups. The estrus lasted 3.6 ± 1.0 days with progesterone at 1.2 ± 0.6 ng / mL and higher frequency of copulations in the final third of this period. Sexual interactions increased during estrus in females (P = 0.0019) and males (P <0.0009), which intensified their frequency of olfactory inspection. Copulations were recorded in the early pregnancy. All pluriparous females (heavier, older and dominant) showed reproductive activity (cyclicity or pregnancy) while seven nulliparous females had periods of anestrus, short (16 days) or long (60 days) in the control group. In the experimental group all nulliparous and primiparous mated and 14 pups were born, however, only five remained after seven days of life. We demonstrate the presence of the dominance of the parents on the progeny and a mechanism for reproductive inhibition in family groupings. We suggest that nulliparous females of reproductive age are relocated from their original group for groups with unrelated males, ensuring the reproductive potential of creation and access to food, space and other resources generally preferred prioritized by dominant individuals.