Journal of Animal Science, Vol 79, Issue 10 2524-2535, Copyright © 2001 by American Society of Animal Science

CLINICAL TRIAL

Vaccination of boars with a GnRH vaccine (Improvac) eliminates boar taint and increases growth performance

F. R. Dunshea, C. Colantoni, K. Howard, I. McCauley, P. Jackson, K. A. Long, S. Lopaticki, E. A. Nugent, J. A. Simons, J. Walker and D. P. Hennessy
Agriculture Victoria, Victorian Institute of Animal Science, Werribee, Australia. Frank.Dunshea@nre.vic.gov.au

Peri- and postpubertal boars accumulate substances (e.g., androstenone and skatole) in their fatty tissue that are responsible for boar taint in pork. The objective of this study was to assess the efficacy of a GnRH vaccine, Improvac, in eliminating boar taint. Three hundred male (200 intact boars, 100 barrows) crossbred (Large White x Landrace) pigs were used in a 2 x 3 factorially arranged experiment. The respective factors were sex group (barrows, boars treated with placebo, or boars treated with Improvac) and slaughter age (23 or 26 wk). Vaccines were administered 8 and 4 wk before slaughter. All Improvac-treated pigs exhibited anti-GnRH titers. Testes and bulbo-urethral gland weights in treated pigs were reduced by approximately 50% (P < 0.001) and serum testosterone levels were below 2 ng/mL in the majority of treated boars (94 and 92% across both age groups at 2 and 4 wk, respectively). Boar taint, as assessed by the concentration of androstenone and skatole in s.c. fat, was suppressed to low or undetectable levels in 100% of Improvac-treated boars. No Improvac-treated pigs had significant concentrations of either androstenone (> 1.0 microg/g) or skatole (> 0.20 microg/g). In contrast, 49.5% of placebo-treated controls had significant androstenone and 10.8% had significant skatole levels, resulting in 10% of the control boars with high concentrations of both compounds. The mean concentrations of taint compounds in the Improvac-treated pigs were not significantly different from those in barrows. Improvac-treated boars grew more rapidly (P = 0.051 and < 0.001 for pigs slaughtered at 23 and 26 wk of age, respectively) than control boars over the 4 wk after the secondary vaccination, possibly because of reduced sexual and aggressive activities. Compared with barrows, Improvac-treated boars were leaner and had superior feed conversion efficiency. The vaccine was well tolerated by the pigs, and no observable site reactions could be detected at the time of slaughter. Vaccination of boars with Improvac allows production of heavy boars with improved meat quality through prevention and control of boar taint.

This article has been cited by other articles:

				C. Rikard-Bell, M. A. Curtis, R. J. van Barneveld, B. P. Mullan, A. C. Edwards, N. J. Gannon, D. J. Henman, P. E. Hughes, and F. R. Dunshea Ractopamine hydrochloride improves growth performance and carcass composition in immunocastrated boars, intact boars, and gilts J Anim Sci, November 1, 2009; 87(11): 3536 - 3543. [Abstract] [Full Text] [PDF]

				R. A. Hill, D. J. Flint, and J. M. Pell Antibodies as molecular mimics of biomolecules: roles in understanding physiological functions and mechanisms Advan Physiol Educ, December 1, 2008; 32(4): 261 - 273. [Abstract] [Full Text] [PDF]

				G. Chen, E. Bourneuf, S. Marklund, G. Zamaratskaia, A. Madej, and K. Lundstrom Gene expression of 3{beta}-hydroxysteroid dehydrogenase and 17{beta}-hydroxysteroid dehydrogenase in relation to androstenone, testosterone, and estrone sulphate in gonadally intact male and castrated pigs J Anim Sci, October 1, 2007; 85(10): 2457 - 2463. [Abstract] [Full Text] [PDF]

				E. N. T. Meeusen, J. Walker, A. Peters, P.-P. Pastoret, and G. Jungersen Current Status of Veterinary Vaccines Clin. Microbiol. Rev., July 1, 2007; 20(3): 489 - 510. [Abstract] [Full Text] [PDF]

				R. K. Naz, S. K. Gupta, J. C. Gupta, H. K. Vyas, and a. G.P. Talwar Recent advances in contraceptive vaccine development: a mini-review Hum. Reprod., December 1, 2005; 20(12): 3271 - 3283. [Abstract] [Full Text] [PDF]

				W. T. Oliver, I. McCauley, R. J. Harrell, D. Suster, D. J. Kerton, and F. R. Dunshea A gonadotropin-releasing factor vaccine (Improvac) and porcine somatotropin have synergistic and additive effects on growth performance in group-housed boars and gilts J Anim Sci, August 1, 2003; 81(8): 1959 - 1966. [Abstract] [Full Text] [PDF]