Efficacy, safety, and reversibility of a bisdiamine male-directed oral contraceptive in gray wolves (Canis lupus)

Cheryl S. Asa, Lourens J D Zaneveld, Linda Munson, Margaret Callahan, Ann P. Byers

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


A trial of the efficacy and safety of the male oral contraceptive bisdiamine (WIN 18,446) was conducted using 10 male gray wolves (Canis lupus) (six treated, four control). During phase I, treated wolves were fed 9 g bisdiamine daily for 5 mo, beginning in early November 1992 before the onset of spermatogenesis. During phase II, two of the previous control males were given bisdiamine daily, beginning in January 1994 after sperm were detected in semen, to determine whether this dosage was sufficient to suppress ongoing spermatogenesis. In addition, reversibility was evaluated in the six previously treated males. Wolves were anesthetized for electroejaculation and blood collection monthly during both phases. At the end of phase I, testicular biopsies were taken for histology. During phase I, sperm first appeared in the semen of control wolves in early December and continued through April. Sperm were seen in five of the six treated wolves, but at very low concentrations compared with controls and after cessation of treatment. All treated males were housed with females, but although at least one was seen mating, none of the females gave birth. Hematologic values remained within the normal range for domestic dogs. Serum chemistry values did not differ between treatment and control wolves, although some values fell outside the normal range for domestic dogs. During phase II, sperm were found in semen samples of all males, although at much lower numbers in those of wolves being given bisdiamine. No deleterious effects were found. These results suggest that the bisdiamine WIN 18,446 is a safe, effective, and reversible oral contraceptive when administered daily to gray wolves. Further work is necessary to clearly establish the minimum dosase required to accomplish infertility.

Original languageEnglish (US)
Pages (from-to)501-506
Number of pages6
JournalJournal of Zoo and Wildlife Medicine
Issue number4
StatePublished - Dec 1996
Externally publishedYes


  • Bisdiamine
  • Canis lupus
  • Contraception
  • Fertilysin
  • WIN 18,446
  • Wolf

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Environmental Science(all)
  • veterinary(all)


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