TRANSRECTAL ULTRASONOGRAPHIC EXAMINATION OF THE FEMALE UROGENITAL TRACT IN NONPREGNANT AND PREGNANT CAPTIVE BEARS (URSIDAE)

The development of reliable methods for monitoring the reproductive cy cle of bears is needed to optimise breeding management in captivity. T he aim of the present study was to develop non-invasive procedures for obtaining basic data on the reproductive status of nonpregnant and pr egnant bears. Eight female captive bears (five Ursus arctos arctos, tw o Tremarctos ornatus and one Melursus ursinus) were examined using tra nsrectal adaptor ultrasonographic imaging. Plasma concentrations of pr ogesterone and gestagens in faeces were determined simultaneously. The ultrasonographic appearance of the female urogenital tract was assess ed during the nonbreeding season and verified in four adult bears post mortem. Pregnant bears were examined twice, as the reproductive physi ology of bears is characterized by delayed implantation and pseudopreg nancy. During embryonic diapause there was no difference between pseud opregnant and pregnant bears both by ultrasonographic imaging and endo crinological data. After implantation (early December) the pregnancies were visualised by ultrasonographic imaging, whereas plasma concentra tions of progesterone and gestagens in faeces had not yet increased. I n conclusion, both transrectal ultrasonographic imaging and gestagen m onitoring in faeces are efficient methods for obtaining important data on reproduction in bears.