Effects of surgical castration, immunocastration and homeopathy on the performance, carcass characteristics and behaviour of feedlot-finished crossbred bulls

Abstract

Effects of surgical castration, immunocastration and homeopathy on the performance, carcass characteristics and behaviour of feedlotfinished crossbred bullsEfeitos da castração cirúrgica, imunocastração e homeopatia sobre o desempenho, características de carcaça e comportamento de bovinos machos cruzados terminados em confinamento AbstractThe aim of this study was to evaluate total weight gain, carcass yield, rib-eye area, marbling, subcutaneous fat thickness, frequencies of mounting, excitement, dominance behaviour and serum testosterone concentration in feedlot-finished non-castrated bulls, surgically castrated bulls, immunocastrated bulls and bulls treated with homeopathy. The study involved 52 calves, Holstein-Zebu, 20±3 months old, in a completely randomised design divided into four treatments of 13 animals: non-castrated, surgically castrated, immunocastrated and non-castrated with homeopathy. Analysis of variance was performed, and the Tukey test was applied (P<0.05). The Pearson correlation coefficient was estimated and principal components analysis was performed. The castrated animals had lower total weight gain and carcass yield than the animals in the remaining treatment groups. The immunocastrated bulls had a greater subcutaneous fat thickness than the non-castrated bulls. The castrated bulls exhibited lower frequencies of mounting, excitement and dominance behaviour than the animals in the remaining treatment groups. Testosterone levels were lower in the castrated animals. Principal components analysis revealed a moderate magnitude and sharpness in the differentiation of the castrated animals. It was concluded that the immunocastrated animals were similar in performance to the non-castrated animals, while the carcass finish characteristics of the immunocastrated animals were similar to the castrated animals. The castrated animals had lower productive performance than the animals in the remaining treatment groups. The homeopathy animals had performance and carcass finish characteristics similar to the non-castrated animals. Homeopathy and immunocastration did not reduce sodomy and dominance behaviours. ResumoObjetivou-se determinar ganho de peso, rendimento de carcaça, área olho lombo, marmoreio, espessura de gordura subcutânea, frequências de monta, excitação, dominância e concentração sérica de testosterona de bovinos não castrados, castrados cirurgicamente, imunocastrados e tratados com homeopatia terminados em confinamento. Utilizou-se 52 garrotes, 3/4 holandês-zebu, 20±3 meses de idade e 303,78±15,78 Kg, distribuídos inteiramente ao acaso em quatro tratamentos de 13 animais: não castrados, castrados cirurgicamente, imunocastrados e não castrados tratados com homeopatia. Fez-se a análise de variância e quando esta foi significativa (P<0,05), aplicou-se o teste de Tukey. Estimou-se o coeficiente de correlação de Pearson entre as variáveis e realizou a análise de componente principal. Os castrados apresentaram menor ganho de peso e rendimento de carcaça que os demais tratamentos e marmoreio super...

Gender status effect on carcass and meat quality traits of feedlot Angus × Nellore cattle

“…The different rib eye areas between treatments could be attributed to the effect of testosterone in bulls (Lee, Henricks, Skelley, & Grimes, ). De Freitas et al () suggested that these differences are possibly because testosterone promotes muscular development throughout bull life due to increased nitrogen retention (Galbraith, Demspter, & Miller, ). Prior, Smith, Schanbacher, and Mersmann () suggested that testosterone has an inhibitory effect on lipogenic enzyme activities present in the adipose tissue, inducing higher basal lipolytic rates.…”

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

“…Other studies have reported a decrease in the frequency of behaviours such as mounting, threats, and head butts in immunocastrated males when compared with uncastrated males (Huxsoll et al 1998, Marti et al 2015, Freitas et al 2015. These differences may be due to the effect that immunocastration has on serum testosterone levels where the synthetic GNRH contained in the vaccine (Bopriva™) stimulates the production of antibodies by the animal immune system.…”

“…The antibodies block the GNRH receptors located in the hypophysis and therefore inhibit the release of the hormones FSH and LH that are responsible for stimulating the production of testosterone in the gonads, and as a result testosterone levels in bloodstream will be reduced (Herbert and Trig 2005). Freitas et al (2015) showed that there is a positive correlation among testosterone levels and the frequency of mounts and agonist behaviour, and they believe that high testosterone levels stimulate a homosexual behaviour. Therefore, when testosterone levels fall, also physical activity will be decreased and so sexual and aggressive behaviour occurrence will be reduced.…”

Características de carcaça e carne de novilhos Aberdeen Angus submetidos à castração cirúrgica ou imunológica

“…Sua utilização justifica-se pelo fato de não infringir dor aguda e desconforto aos bovinos, quando em relação à castração cirúrgica (Marti et al, 2015). Alguns estudos têm sido desenvolvidos visando avaliar os efeitos dos métodos de castração, castração imunológica ou cirúrgica, sobre características de carcaça e carne em bovinos de corte (Amataiakul-Chantler et al, 2013;Miguel et al, 2014;Freitas et al, 2015). Todavia, nesses estudos, os dois métodos de castrações foram aplicados em períodos imediatamente anteriores à fase de engorda, logo em bovinos com idade pós-púbere.…”