Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2003
Publication Date: 10/1/2003
Citation: LOOPER, M.L., LENTS, C.A., WETTEMANN, R.P. 2003. BODY CONDITION AT PARTURITION AND POSTPARTUM WEIGHT CHANGES DO NOT INFLUENCE THE INCIDENCE OF SHORT-LIVED CORPORA LUTEA IN POSTPARTUM BEEF COWS. JOURNAL OF ANIMAL SCIENCE. 81(10):2390.
Interpretive Summary: Cows calving on a 365-day cycle is important to the sustainability of a cattle operation, but the relationship between cows's body condition and the resumption of reproductive processes postpartummly are poorly understood. In this study, luteal activity of beef cows calving in thin to moderate body condition was evaluated to determine effects of body condition on duration of first luteal activity. We found that cows in thin condition had longer intervals from calving to first estrus, luteal activity, and conception. This information is of interest to extension personnel and agricultural professionals who advise producers on reproductive management.
Technical Abstract: Seventy-seven multiparous beef cows calving with thin to moderate body condition scores (BCS) were utilized to evaluate the effects of body condition at parturition and BW change post partum on duration of the first luteal activity and on occurence and duration of luteal activity after first estrus. Cows were exposed to bulls and observed twice daily for behavioral estrus. Luteal activity was classified as normal if plasma concentrations of progesterone were > 0.5 ng/mL for at least 11 d or short if concentrations of progesterone were > 0.5 ng/mL for 10 or less days. The interval from parturition to first normal LA was shorter (P < 0.0001) for moderate condition (BCS > 4.5) than for thin (BCS < 4) cows (58.3 vs 93.3 d, respectively). Interval to first estrus also was shorter (P < 0.0001) for moderate than for thin cows (53.3 vs 89.3 d, respectively). Seventy-eight percent of cows had an increase in progesterone for < 11 d preceding the first normal LA. Postpartum weight change and BCS at calving did not influence the incidence of estrus associated with first normal LA. After the first estrus, 72% of cows had normal LA, 16% had short LA, and 12% lacked LA. Postpartum weight change and BCS did not influence the length of LA associated with the first estrus. Cows with normal LA had increased (P < 0.05) maximum concentrations of progesterone compared with cows that had short LA. Eighty-one percent of cows with a transient increase in progesterone prior to first behavioral estrus exhibited normal luteal function after estrus. Postpartum BW change and BCS at calving did not influence the duration of luteal activity after the first estrus in beef cows.