Induction of oestrus with norgestomet in acyclic post-pubertal holstein heifers

Cetin Y., Uslu B. A., Gungor O., Sendag S.

BULLETIN OF THE VETERINARY INSTITUTE IN PULAWY, vol.51, no.2, pp.247-251, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 51 Issue: 2
  • Publication Date: 2007
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.247-251
  • Van Yüzüncü Yıl University Affiliated: Yes


The study was carried out during April and May 2006, on thirty-eight 15 - 23-month-old Holstein heifers with inactive ovaries, which were selected from a private dairy herd with 300 heifers. The heifers were randomly distributed into two groups: norgestomet group (n=29), and a control group (n=9). In the norgestomet group, silicone ear implants containing 6 mg of norgestomet were implanted, and a solution containing 3 mg of norgestomet and 5 mg of oestradiol valerate was injected intramuscularly. The silicone implants were removed 11 d later, and the heifers were continuously observed for signs of oestrus for three days. The heifers were inseminated 48 and 78 h after the removal of the implants, and after the first insemination they were treated with 50 tg of GnRH analogue. The rate of the induced oestrus was 86.2% (25/29) and 0% (0/9) in norgestomet and control groups, respectively. The pregnancy rate was 48.2% (14/29) and 0% (0/9) in norgestomet and control groups, respectively. Our results showed that fertile oestrus can be stimulated successfully in post-pubertal heifers with inactive ovaries by a norgestomet treatment, and successful pregnancy rate can be obtained by a fixed-time insemination during this oestrus.