Seasonal changes in ovarian steroid hormone concentrations in the large hairy armadillo (Chaetophractus villosus) and the crying armadillo (Chaetophractus vellerosus)

J.P. LUACES; M. CUCCIO; L. ROSSI; A. FALETTI; P. CETICA; E. CASANAVE; M.S. MERANI

THERIOGENOLOGY

ELSEVIER SCIENCE INC

Año: 2011 vol. 75 p. 796 - 802

0093-691X

Knowledge of armadillo reproductive physiology is essential for developing ex situ and in situ assisted reproductive techniques for propagating and/or control its population. The present work describes the estimation of fecal sex steroids by radioimmunoassay, determining reproductive status via monitoring ovarian activity in wild and therefore reproductive status, in wild females of the large hairy armadillo (Chaetophractus villosus) and the crying armadillo (Chaetophractus vellerosus) in the southern hemisphere. Plasma and fresh fecal progesterone concentrations did not correlate in either species.  However, a significant positive correlation was observed between the plasma progesterone and dry fecal progesterone concentration in both (r=0.82, P <0.05 and r=0.60, P <0.05 respectively).  Dry fecal progesterone and estradiol concentrations were measured in one captive female of C. villosus (average baseline progesterone and estradiol concentrations 28.72 ± 11.75 ng/g dry feces and 3.04 ± 0.80 ng/g dry feces, respectively) and one captive female of C. vellerosus (average baseline progesterone and estradiol concentrations 14.05 ± 3.03 ng/g dry feces and 3.46 ± 1.20 ng/g dry feces, respectively) to detect hormonal peaks over one year; these were observed from late fall to early summer. Feces from wild females of C. villosus and C. vellerosus were also collected over one year to determine progesterone peaks.  These occurred in winter and spring in both species; no peaks were observed during the summer or fall. Accordingly, C. villosus and C. vellerosus show a seasonal reproductive pattern. The correlation established between dry fecal and plasma progesterone concentrations validates this methodology as a means of monitoring reproductive status in these species.