Influence of follicular ablation during lactation on postweaning interval to estrus, ovulation rate, and endocrine function in sows

N. M. Cox, J. D. Armstrong, J. H. Britt

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Duroc sows farrowed second litters in March and lactated 35 ± 2 days. At 36 hr before weaning, electrocautery of follicles ≥3 mm in diameter (n=8) or sham surgery (n=5) was performed to test the hypothesis that ablation of medium-sized follicles would prolong the duration of postweaning anestrus. Number of follicles and diameters at surgery were: 1.3 ± .6 (> 5 mm diameter), 26 ± 1 (3 to 5 mm) and > 20 (< 3 mm). Blood samples were collected at 15 min intervals for 3 hr beginning at -12, 0, 12, 60 and 96 hr from weaning. Interval to estrus was 3.4 ± .2 days in seven of eight cauterized sows and 3.6 ± .6 days for sham-surgery sows. The remaining cauterized sow was anestrus at slaughter, 40 days after weaning. Number of corpora lutea and pregnancy rate were 15.8 ± .6 and 92%, respectively, and were similar between sham-surgery and cauterized sows. Concentration of follicle stimulating hormone (FSH) at 12 hr before weaning was greater in sows subjected to electrocautery than for sham-surgery sows, but FSH values were similar at other sampling times. Concentrations of estradiol were similar at all times for both treatment groups. Luteinizing hormone (LH) was higher (P<.05) at 60 hr in cauterized sows because of the onset of the preovulatory LH surge in one sow. We conclude that destruction of medium-sized ovarian follicles before weaning did not influence postweaning reproductive performance.

Original languageEnglish
Pages (from-to)87-93
Number of pages7
JournalDomestic Animal Endocrinology
Issue number2
StatePublished - Apr 1987

Bibliographical note

Funding Information:
This research was supported in part by grant 82-CRSR-2-1069 from the United States Department of Agriculture. Porcine LH (LER 783-6) for radioimmunoassays was provided by L.E. Reichert, Jr., Albany Medical College, Albany, NY. LH antiserum was provided by G.D. Niswender, Colorado State University, Ft. Collins, CO. Porcine FSH (IA3-c2) and FSH antiserum was provided by R.J. Ryan and R.J. Whitley, Mayo Clinic, Rochester, MN. Estradiol-17\]3 antiserum was provided by N.R. Mason, Lilly Research Laboratories, Indianapolis, IN. tPaper No. 10477 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC, 27695-7601, USA. The use of trade names in this paper does not imply endorsement by the North Carolina Agricultural Research Service of the products names, nor criticism of similar ones not mentioned. 2Department of Animal Science, Mississippi State University, Mississippi State, MS, 39762, USA. 3Reprint requests.

ASJC Scopus subject areas

  • Food Animals
  • Animal Science and Zoology
  • Endocrinology


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