Case studies in antelope aggression control using a GnRH agonist

Abstract

Maintaining surplus captive male antelope in bachelor groups can result in aggression in some species, leading to injury or death. Suppressing endogenous testosterone using gonadotropin‐releasing hormone (GnRH) analogs has been used in primates to control aggressive behavior, but little information is available on the use of GnRH analogs in nondomestic ruminant species. The aim of this study was to investigate the effect of a slow‐release GnRH agonist (deslorelin) on circulating hormone concentrations, semen and sperm characteristics and behavior in male gerenuk, dorcas gazelle, and scimitar horned oryx. Body weight, testicular volume, circulating hormone concentrations, ejaculate traits, and behavior were recorded before and during deslorelin treatment. A GnRH challenge (with serial blood sampling) was administered to gerenuk and dorcas gazelles before and during GnRH analog treatment. Quantitative behavioral data were collected for gerenuk and dorcas gazelles for 30 min three times a week, starting 1 month before deslorelin treatment, and the mean incidence of combined aggressive behaviors (supplanting, foreleg kicking, sparring, marking, and mounting) was compared before and during deslorelin treatment. No statistical difference (P>0.05) in body weight, semen volume, sperm concentration, percent sperm motility, percent sperm plasma membrane integrity, or percent normal sperm morphology was found before or during deslorelin treatment. The characteristic rise in luteinizing…