METHODS FOR PREGNANCY DETERMINATION AND THE EFFECTS OF BODY CONDITIONON PREGNANCY STATUS IN ROCKY-MOUNTAIN ELK (CERVUS-ELEPHUS-NELSONI)

The objective of this study was to determine the effectiveness of tran srectal ultrasonography and serum progesterone (P-4), estrone sulfate (E(1)S) and pregnancy-specific protein B (PSPB), without prior knowled ge of reproductive status, in detecting pregnancy in elk cows. In addi tion, body weight and body condition score (BCS) were determined to as sess whether body condition affects pregnancy status in elk cows. Twen ty-five elk cows were sampled during the early rut (Period 1) and afte r the rut (Period 2), an interval of 120 d. Age, weight, BCS and blood samples, for P-4, E(1)S and PSPB determinations, were taken at Period s 1 and 2. Ultrasonography was performed at Period 2. The younger elk cows weighed less (P<0.05) than older cows. However, pregnancy status was not affected (P>0.10) by age or weight of the cow. Elk cows that c alved had higher (P<0.02) BCS at Periods 1 and 2 than cows that remain ed open. Serum P-4 and E(1)S were higher (P<0.0001) in pregnant cows a t Period 2 than in open cows. Progesterone was 85.8% accurate in detec ting pregnant versus open cows at Period 1, while E(1)S and PSPB were not effective. Elk cows at Period 1 were <20 d pregnant with the excep tion of 1 cow at 46 d. Ultrasonography was 92% accurate, P-4 was 95% a ccurate, and E(1)S and PSPB were both 100% accurate in determining pre gnant versus open cows at Period 2. Pregnant cows at Period 2 were all >100 d pregnant. Ultrasonography, serum E(1)S and PSPB all may provid e a reliable means for pregnancy diagnosis in elk cows at >100 d of ge station, while serum P-4 may be effective when multiple samples are co mpared during or after the rut, or when used in combination with the o ther diagnostic methods described. Further research is needed to deter mine the optimum time period after breeding in elk cows for accurate p regnancy detection through hormonal analysis.