Ovulation potential of human chorionic gonadotropin versus GnRH

Date

2010-11-29

Journal Title

Journal ISSN

Volume Title

Publisher

Kansas State University. Agricultural Experiment Station and Cooperative Extension Service

Abstract

Experiments have shown human chorionic gonadotropin (hCG) to be more effective than GnRH as a means to induce ovulation of folli-cles. Dosages used, however, have differed greatly among experiments. A study was per-formed to determine the minimum effective dose of hCG needed to induce ovulation of ovarian follicles in dairy cows. Ovaries of Holstein cows were mapped by using transrec-tal ultrasonography 7 days before a bi-weekly pregnancy diagnosis. Cows were assigned randomly to treatments of saline, 100 μg of GnRH (2 mL of Fertagyl, Intervet, Inc., Mills-boro, NJ), or 500, 1000, 2000, or 3000 IU of hCG (0.5, 1, 2, or 3 mL of Chorulon, Intervet, Inc., Millsboro, NJ). Ovarian structures were monitored again 7 days later, and the propor-tion of cows, and proportion of follicles ≥ 8 mm in diameter, that ovulated were recorded. A dose of at least 1000 IU of hCG resulted in a greater ovulatory response than saline, GnRH, or 500 IU of hCG.

Description

Dairy Research, 2006 is known as Dairy Day, 2006

Keywords

Dairy, GnRH, hCG, Ovulation

Citation

Collections