Comparison of pregnancy detection methods in live white-tailed deer

Assessing ungulate reproduction is important to biologists for managing populations and predicting trends. We compared efficacy of trans-abdominal ultrasound and pregnancy-specific protein B (PSPB) white-tailed deer (Odocoileus virginianus) pregnancy estimates, respectively, from January to mid-April 2009–2011 in the south-central Upper Peninsula of Michigan, USA. We observed a strong agreement (K= 0.68, SE = 0.13, 95% CI = 0.42–0.94) of PSPB and ultrasound in categorizing pregnant and nonpregnant deer. Five deer were determined to be pregnant by ultrasound but not by PSPB and 6 females were judged to be nonpregnant using either method. Total cost for PSPB testing of 101 deer was US$2,220, whereas ultrasound equipment cost US$14,150. Trans-abdominal ultrasound and PSPB provided accurate detection of pregnancy in live white-tailed deer. We recommend PSPB for studies testing comparatively small numbers (up to several hundred) of deer. However, we recommend ultrasonography if real-time pregnancy determination is needed (e.g., vaginal implant transmitter use), particularly for large numbers (i.e., several hundred to thousands) of deer.