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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #193868
Title: RESUMPTION OF POSTPARTUM LUTEAL FUNCTION OF PRIMIPAROUS, SUCKLED BEEF COWS EXPOSED CONTINUOUSLY TO BULL URINE

Author
item TAUCK, S - MSU BOZEMAN
item BERARDINELLI, J - MSU BOZEMAN
item Geary, Thomas
item JOHNSON, N - MSU BOZEMAN

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2006
Publication Date: 10/1/2006
Citation: Tauck, S.A., Berardinelli, J.G., Geary, T.W., Johnson, N.J. 2006. Resumption of postpartum luteal function of primiparous, suckled beef cows exposed continuously to bull urine. Journal of Animal Science 84:2708–2713.

Interpretive Summary: The objective of this experiment was to determine if continuous exposure to bull urine alters resumption of ovarian cycling activity of primiparous, suckled beef cows. Neither interval from urine exposure to resumption of luteal activity nor proportions of cows that resumed luteal activity during the urine-exposure period differed between bull urine exposure and steer urine exposure cows. We conclude that continuous exposure to mature bull urine does not affect resumption of luteal activity of primiparous, suckled beef cows.

Technical Abstract: We tested the hypotheses that interval from urine exposure to resumption of luteal activity and proportions of cows that resume luteal activity by the end of the urine-exposure period do not differ between cows exposed to mature bull urine or steer urine. Thirty-eight Angus x Hereford cows, four mature A x H bulls and four ten-mo-old A x H steers were used in this study. Cows were stratified by calving date, cow BW, calf BW, calf sex, dystocia score, and BCS, and fitted with a controlled urine delivery device (CUDD) two wk before the start of treatments, and assigned randomly to be exposed continuously (24h/d) to bull urine (BUE; n = 19) or steer urine (SUE; n = 19) beginning 40 d after calving. Urine was collected from bulls and steers every third d of the experiment. Blood samples were collected from cows starting on d 0 and every third d thereafter until end of the exposure period (~64 d). Likewise, CUDD were filled and refilled on the same schedule. Serum was assayed for progesterone by RIA. Neither interval from urine exposure to resumption of luteal activity nor proportions of cows that resumed luteal activity during the urine-exposure period differed between BUE and SUE cows. We conclude that continuous exposure to mature bull urine does not affect resumption of luteal activity of primiparous, suckled beef cows.