Skip to main content
ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Livestock Bio-Systems » Research » Publications at this Location » Publication #208202
Title: Increasing ovulation rate reduced follicle size and increased blood progesterone concentrations but had no effect on fertility in cattle selected for twins

Author
item Echternkamp, Sherrill
item Cushman, Robert - Bob
item Allan, Mark

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/6/2007
Publication Date: 6/20/2007
Citation: Echternkamp, S.E., Cushman, R.A., Allan, M.F. 2007. Increasing ovulation rate reduced follicle size and increased blood progesterone concentrations but had no effect on fertility in cattle selected for twins [abstract]. Journal of Animal Science. 85 (Supplement 1):649. (Abstract #886)

Interpretive Summary:

Technical Abstract: Smaller ovulatory follicles (F) and lower progesterone concentrations during the luteal phase after breeding reportedly decrease fertility and embryonic survival in cattle. Diameter (diam.) of individual F and corpora lutea (CL), blood progesterone concentrations, and conception to AI were compared among cows with ovulation rate (OR) records of one (n = 74), two (n = 253), three (n = 88), or four (n = 6) CL in 2004 to 2006; herd mean for OR was 2.09. Number and diam. of F and subsequent CL were determined by ultrasonography at 12 h after onset of estrus and 8 to 15 d after AI, respectively, and number of fetuses at 60 d after AI. Progesterone was quantified by RIA in a single blood sample collected at CL diagnosis. Data were analyzed by SAS PROC MIXED procedures; main effects in the models were OR, day, fetal status, and year. Follicle diam. was smaller (P < 0.01) in 2006. Follicle and CL diam. were correlated (r = 0. 53; P < 0.01) and decreased (P < 0.01) with increasing OR (1 CL = 17.1 ± 0.3 and 23.3 ± 0.4 mm, 2 CL = 14.0 ± 0.1 and 20.2 ± 0.4 mm, 3 CL = 12.6 ± 0.2 and 18.1 ± 0.3 mm, 4 CL = 11.7 ± 0.5 and 16.7 ± 0.7 mm, respectively), but diam. were similar for fertile (fetus) and infertile ovulations (13.9 ± 0.1 and 19.8 ± 0.4 mm vs. 13.8 ± 0.1 and 19.4 ± 0.4 mm, respectively). Fetal number per female increased (P < 0.01) with OR (0.52 ± 0.8, 1.07 ± 0.5, 1.52 ± 0.6, and 1.63 ± 1.0 for 1, 2, 3, and 4 CL, respectively), but the fetus:ovulation ratio (0.52 ± 0.3) was unaffected by OR. OR did not affect pregnancy rate (65.6 ± 0.3%) at d 60. Progesterone concentrations increased (P < 0.01) with OR (1 CL = 7.1 ± 0.3, 2 CL = 8.9 ± 0.2, 3 CL = 9.7 ± 0.3, 4 CL = 8.5 ± 0.7 ng/ml) and from d 8 (6.3 ± 0.5 ng/ml) to 14 (10.6 ± 0.5 ng/ml). Concentrations did not differ between pregnant and nonpregnant cows (8.8 ± 0.3 vs. 8.2 ± 0.3 ng/ml). Decreased follicle size and increased progesterone in cows with natural multiple ovulations did not affect conception.