Seasonality of reproduction in wild boar (Sus scrofa) assessed by fecal and plasmatic steroids

The collection of biological samples through non-invasive techniques represents one way of monitoring in vivo physiologic changes associated with reproductive activity. Such techniques are particularly important for the study of animal species in thewil The goals of this study were 1) to evaluate fecal progestogen (P), estrogen (E), and androgen (A) by means of radio immunoassays, in male and female wild boars culled in the Piedmont, Italy area; 2) to compare them with plasmatic concentration and the animals’ reproductive status; and 3) to assess variations in reproductive seasonality between two populations of wild boar living in a mountainous vs. a plain habitat in Piedmont. The results demonstrate a positive correlation between fecal and plasmatic steroid concentrations (r = 0.46, 0.58, and 0.45 fo plasma P4 and P, E2 and E, and T and A; P < 0.05). Moreover, high fecal levels of both P and E (>170 ng/g and >100 pg respectively) were found in 70.6% of pregnant sows and in none of the non-pregnant animals, thus supporting the use of th technique for detecting pregnancy status in wild boar. Similar birth patterns were displayed by themountain and plain populations, but births peaked significantly only in themounta population, in the spring (46%, P < 0.05, vs. other seasons). A corresponding autumnal peak of plasma testosterone concentration in males was displayed only by the mountain population (7.4 vs. < 2.0 ng/mL in the other seasons, P < 0.05). The correlation between fecal and plasmatic steroid concentrations obtained in this study supports the applicability of this non invasive sampling technique for monitoring reproductive status in wild boar, thus enabling a more informed and corre management of the species.