Effects of a 200 µg Dose Canine Gonadotropin Releasing Hormone Vaccination on Mares

Introduction

EquityTM (Pfizer Australia Pty, Ltd, West Ryde, NSW, Australia)) is an equine gonadotropin releasing hormone (GnRH) vaccine (containing 200 μg of GnRH peptide) labeled for estrus suppression available in Australia and New Zealand. Canine Gonadotropin Releasing Factor Immunotherapeutic (Pfizer Animal Health, Exton, PA) is a canine GnRH vaccine labeled for benign prostatic hyperplasia manufactured in the U.S. Our laboratory has previously shown that a 5X dose of the canine GnRH vaccine (1000 μg of GnRH peptide) safely suppresses estrous cyclicity in mares. The objective of this study was to determine if a lower dose of the canine GnRH vaccine (200 μg of GnRH peptide; the labeled canine dose) would suppress estrous cyclicity in mares. Our hypothesis was that GnRH antibody titers would be lower but still sufficient to prevent equine estrous cyclicity and behavior. [...]