IMMUNO-CASTRATION BY IMMUNIZATION WITH GnRH IN BLACK BENGAL BUCKS (CAPRA HIRCUS)

Explor Anim Med Res, ISSN 2277- 470X (Print), ISSN 2319-247X (Online) 2019 www.animalmedicalresearch.org Vol.9, Issue - 1, 2019, p. 54-60 Exploratory Animal and Medical Research, Vol.9, Issue 1, June, Website: Research Article IMMUNO-CASTRATION BY IMMUNIZATION WITH GnRH IN BLACK BENGAL BUCKS (CAPRA HIRCUS) A.K. Mandal1*, A. Maity2 Received 28April 2019, revised 21 June 2019 ABSTRACT: The present study was carried out to elucidate the castration effects of immunization against GnRH (Gonadotropin releasing hormone) in Black Bengal bucks. Thirty (30) Black Bengal bucks under study were divided into three groups, viz. Group I (control animals), Group II (surgical castrates) and Group III (immunized bucks). Anti-GnRH antibody titer was measured from the blood samples collected from Group III animals on days 0, 1, 3, 5, 7, 15, 30, 45, 60, 85, 100, 115. Plasma testosterone and cortisol level were also measured for all blood samples collected (during the said period) from all the animals. The increased antibody titer in bucks about 45-50 days after primary immunization coincided with the decreasing plasma testosterone level during the same period. No significant anti-GnRH activity was observed in the control as well as surgically castrated bucks. Plasma testosterone level increased progressively during the experimental period in the control group, whereas surgical castrates showed a marked reduction in testosterone level soon after the castration. The immunized bucks were under less stress condition than the surgically castrated ones as indicated by their plasma cortisol concentration. Both the surgical and immuno-castrates were easily handled and managed during the experimental period due to a marked reduction in sexual behavioral measures than the control group. So, the immunization against GnRH may be a non-invasive, convenient alternative to the surgical castration. Key words: Immuno - castration, GnRH immunization, Black Bengal bucks. dosing of chemical agents (in case of chemical castration) may even lead to the fatality (FDA 2003). INTRODUCTION The domestic male animals are commonly castrated to improve meat quality, reduce aggressive behavior and for easy management practices (Kiyma et al. 2000). There are a number of methods available for castration of male animals, namely surgical method (Walker and Vaughan 1980), Burdizzo or clamping techniques to crush the spermatic cords (Macaulay 1989), chemical castration (Kar et al. 1965, Cohen et al. 1990, Mitra and Samanta 2000). Such techniques of castration, however, have some demerits (primary insult and secondary consequences). Moreover, all these castration methods require additional labor, increase stress, reduce efficiency and decrease the rate of weight gain of the subjected animals. Improper Rising consumer awareness about the welfare of production animals, with the physical castration of livestock receiving considerable attention was emphasized in the Global Meat News’ State of the Industry Survey Report (2015) as well as in the European Union’s decision to voluntarily ban the physical castration of piglets without anesthesia from 2018 (Font-i-Furnols et al. 2012). Despite a faster growth rate and superior feed efficiency of intact males than castrates (Sales 2014), various management and welfare issues exist regarding the raising of intact males (Price et al. 2003). Heavy intact male carcasses 1 Department of Veterinary Anatomy and Histology, 2 Department of Veterinary Biochemistry, Faculty of Veterinary and Animal Sciences, West Bengal University of Animal & Fishery Sciences, Kolkata-700 037, West Bengal, India. *Corresponding author. e-mail: 54 Immuno-castration by immunization with GNRH in Black Bengal Bucks (Capra hircus) also suffer from various meat quality issues at the abattoir. Thus, boars over 100 kg (approximately 22 weeks old) and bulls or rams with one or more permanent incisors receive a lower price tag. There is thus a need to formulate alternative management practices to ensure efficient growth of male animals resulting in optimum carcass and meat quality, without compromising animal welfare (Needham et al. 2017). Accordingly, the alternative methods of castration aimed to alleviate stress and discomfort as compared to the conventional procedures are of great interest. Techniques have been developed to achieve many of the effects of castration by inducing immuno-neutralization of hormones of the hypothalamic-pituitary-testicular axis (Adams and Adams 1992, Finnerty et al.1996). Active immunization against GnRH, commonly known as immuno-castration, has been proposed as an alternative to traditional methods in bulls (Robertson et al. 1979). It is relatively non-invasive and less stressful procedure. Such immunization against GnRH is reported to suppress testicular growth as well as secretory activity in ram lambs (Schanbacher 1982, Cui et al. 2003, Ulker et al. 2005). Moreover, immunoneutralization of GnRH inhibits spermatogenesis and decreases reproductive and aggressive behavior in domestic animals (Awoniyi et al. 1988, Jago et al. 1997, Rydhmer et al. 2010). Immuno-castration of pigs with a gonadotrophin releasing factor (GnRF) vaccine ‘Improvac TM’ (Pfizer Ltd) significantly reduces the occurrence of unwanted aggressive and sexual behaviors compared with unvaccinated control male pigs (Brewster and Nevel 2013). Much works were done in this regard in bull, stallion, pig and rams. But there is meager information on the immuno-castration of male goats (bucks). Black Bengal goats are well-known world-wide for its very good quality chevon. Keeping all these facts in view, the present study was designed to establish immuno-castration as a non-invasive and easy-to-do alternative to surgical castration in Black Bengal bucks that could also be of much interest to the people associated with the animal welfare movement. experiment. Accordingly, necessary corrective measures like vaccination, deworming etc. were undertaken. The animals were randomly allocated to three groups, each containing ten bucks (n = 10). Group I bucks were used as control animals (C), Group II animals for surgical castration (SC) and the remaining Group III animals for immunological castration (IC). Control animals (Group I) were intact, non- castrated and non-immunized bucks. Surgical castration was routinely performed in Group II animals following usual anesthetic procedure and asepsis. All the bucks were maintained in individual pens and were fed the standard commercial diet with ad-libitum safe drinking water throughout the experimental period. The animal house was properly lighted and well ventilated. Before commencement of the experiment the necessary permission was obtained from the “Institutional Animal Ethical Committee”, College of Veterinary Science and Animal Husbandry, Bhubaneswar. All the experimental procedures and protocols were duly approved by the committee. Immunization procedure Active immunization agai (...truncated)