Aggressive behavior is reduced in bulls actively immunized against gonadotropin-releasing hormone1

Abstract

The purpose of this research was to compare the frequency of aggressive behavior's in beef bulls actively immunized against gonadotropin-releasing hormone relative to contemporary nonimmunized control bulls and surgically castrated steers. Eight males were assigned to each ofthese treatments in each of 4 yr. Immunized males were treated with a GnRH-keyhole-limpet hemocyanin (KLH) conjugate at approximately 4 mo of age. A secondary (booster) immunization was administered at 12 mo. Steers were castrated at 4 mo of age. Animals in each treatment in each year were housed as a single group prior to testing. At approximately 16 mo of age, each group of eight animals was placed in a 10- x 16-m enclosure for 20 min on five occasions at 2 to 3 d intervals. An observer recorded butts initiated by each animal as well as participation in bouts of sparring. Relative to control bulls, immunocastration reduced the frequency of butts initiated (P < 0.05) and participation in sparring bouts (P < 0.05) to levels typically observed in steers (P > 0.05). These observations indicate that active immunization against GnRH reduces the incidence of aggressive behavior in male beef cattle and are consistent with our postulate that immunoneutralization of GnRH is an effective alternative to surgical castration in the management of beef cattle.

Vaccination against gonadotropin-releasing factor (GnRF) with Bopriva significantly decreases testicular development, serum testosterone levels and physical activity in pubertal bulls

“…From previous studies with Bopriva ® [13,20] it has been shown that body temperature increased for 1-2 days after both vaccinations without displaying any clinical signs of apathy. The above observations indicate that the ALPRO  DeLaval activity meter system represents a very sensitive tool to detect behavioral changes in bulls and confirm the results of earlier studies where behavior of vaccinated animals was subjectively assessed [6,9,13,20,40,41]. In this regard Jago et al [9] found that bulls vaccinated with the GnRF vaccine Vaxstrate  showed reduced homosexual mounting, agonistic behavior and damage to pasture, and concluded that immunocastration could provide a practical alternative to traditional methods for bull behavior control.…”

“…Currently Bopriva  is the only anti-GnRF vaccine available for cattle on the market and has demonstrated good efficacy and safety in a pilot project [13] with young bulls. The latter and several other studies [6,9,20,40,41] have shown that anti-GnRF based vaccines to be efficacious at suppressing testosterone driven sexual and aggressive behavior. In these investigations behavior was only assessed subjectively but no information is available in the literature about behavior changes in vaccinated bulls analyzed objectively by using an electronic activity meter system.…”

Immunocastration reduces aggressive and sexual behaviour in male pigs

“…Cronin et al (2003) also found that immunocastrated pigs performed less aggressive behaviour than entire male pigs. Furthermore, immunocastration has been shown to reduce aggressive behaviour in bulls (Price et al, 2003;Huxsoll et al, 1998) and bucks (Godfrey et al, 1996).…”

Effect of immunocastration on behaviour and blood parameters (cortisol and testosterone) of Holstein bulls

“…However, this practice affects the welfare of animals due to acute or chronic pain caused for the procedure (Rault et al 2011). Traditional castration methods are associated with high level of stress, reduction in growth rate, pain, long recovery periods (Becker et al 2012), and post-operative infections (Price et al 2003).…”