Multiple ovulation resulting from low level administration of PMSG to cattle at different stages of the oestrous cycle

G. B. Anderson, Robert Bondurant

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Two experiments were carried out to determine whether differences in sensitivity to exogenous gonadotrophin which exist during the oestrous cycle can be used effectively in the induction of multiple pregnancy in cattle. In Experiment I, Hereford heifers and cows were injected with 800 IU pregnant mare serum gonadotrophin (PMSG) on approximately day 10 of the oestrous cycle, followed 48 h later by 30 mg prostaglandin F (PGF). Controls were treated with PGF alone. Mean ovulation rates based on rectal palpation were 1.33 ± 0.10 (range: 1-2) and 3.05 ± 0.68 (range: 1-13) for 21 control and 21 treated animals, respectively (P < 0.02). In Experiment II, Hereford cows were treated with 800 IU PMSG on either day 5 (14 cows) or day 10 (12 cows) of the oestrous cycle, followed 48 h later by PGF. Mean numbers of ovulations for animals that became pregnant were 1.50 ± 0.26 (range 1-3) and 3.80 ± 0.74 (range 1-7), respectively (P < 0.02). A high incidence of embryonic wastage occurred by 120 days of gestation in animals treated on day 10. The results of this study indicate that taking advantage of an animal's reduced responsiveness to exogenous gonadotrophin during the early portion of the oestrous cycle may be useful in developing methods for inducing multiple births with exogenous gonadotrophins.

Original languageEnglish (US)
Pages (from-to)85-91
Number of pages7
JournalAnimal Reproduction Science
Volume5
Issue number2
DOIs
StatePublished - Jan 1 1982

ASJC Scopus subject areas

  • Food Animals
  • Animal Science and Zoology
  • Endocrinology

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