O temperamento de bovinos confinados em diferentes disponibilidades de espaço e suas relações com o desempenho e a qualidade da carcaça e da carne
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Data
2016-02-29
Autores
Braga, Janaina da Silva [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo foi avaliar os efeitos do temperamento de bovinos confinados em diferentes disponibilidades de espaço (6, 12, e 24 m2/animal) no desempenho, na qualidade da carcaça e da carne bem como no bem-estar animal. Como objetivos específicos, destacamos: 1) avaliar os efeitos do espaço disponível no temperamento; 2) avaliar os efeitos do temperamento no desempenho e na qualidade da carcaça e da carne de bovinos confinados em diferentes disponibilidades de espaço; 3) avaliar os efeitos do temperamento na morfometria das glândulas adrenais e suas relações com a disponibilidade de espaço; 4) determinar a relação entre a morfometria das glândulas adrenais e a severidade dos hematomas nas carcaças bovinas, em diferentes disponibilidades de espaço. Foram avaliados 1.350 machos inteiros (450 Nelore e 900 cruzados Angus ou Caracu x Nelore) criados no pasto e terminados em um confinamento comercial. Temperamento foi avaliado pelo teste de velocidade de saída (VS) nos dias 0 (VS0), 35 (VS35) e 87 (ou dia final: VSfin) do período de confinamento. Desempenho, características de qualidade da carcaça, pH24h da carne, morfometria da adrenal e severidade dos hematomas nas carcaças foram avaliados. A VS diminuiu ao longo do período de confinamento (p < 0.01). No geral, VS não diferiu entre os animais mantidos em diferentes disponibilidades de espaço (p = 0.79) nem entre raças (p = 0.16). Interação entre espaço disponível e raça ou entre espaço disponível e VS0 ou VSfin não apresentaram nenhum efeito sobre as variáveis de desempenho ou características de qualidade de carcaça e carne (p > 0.05). Entretanto, animais calmos de acordo com a VSfin tiveram maior ganho de peso do dia 0 ao 35 (p < 0.0001) e estavam mais pesados no dia 35º (p < 0.0001) e 87º (p < 0.01) dia do confinamento e, consequentemente, produziram carcaças mais pesadas (p < 0.01) comparados aos intermediários e reativos. Independente do espaço disponível e da raça, animais reativos de acordo com VS0 apresentaram glândulas adrenais mais pesadas (p < 0.01) e com maior perímetro (p = 0.01) quando comparados com os calmos. Adicionalmente quando mantidos em reduzidos espaços disponíveis (6 ou 12 m2 por animal), os animais reativos apresentaram maior área cortical. Com relação à severidade dos hematomas, animais com glândulas adrenais com maior área medular, maior perímetro e mais pesadas (p < 0.05), mantidos em 6 ou 24 m2 por animal apresentaram maior severidade dos hematomas nas carcaças. Concluímos que as condições de confinamento aplicadas nesse estudo melhoraram o temperamento dos bovinos ao longo do tempo e que, independente do espaço disponível e da raça, os animais calmos apresentaram melhor desempenho produtivo do que os intermediários e reativos. A capacidade do animal em adaptar-se ao sistema de produção intensiva contribuiu favoravelmente para a qualidade da produção. Ainda, reduzido espaço disponível apresentou mais efeitos deletérios no bem-estar de animais reativos do que dos calmos. Além disso, animais mais estressados são mais prováveis de apresentar hematomas severos nas carcaças.
The aim of this study was to evaluate the effects of bulls’ temperament kept at three different space allowances (6, 12, and 24 m2/animal) on growth performance, carcass traits, meat quality traits and animal welfare. The specific objectives were: 1) to evaluate the effects of space allowance on bulls’ temperament; 2) to evaluate the effects of temperament on growth performance, carcass and meat quality traits of beef cattle kept in different space allowance; 3) to evaluate the effects of temperament on adrenal gland morphometric and its relationship to space allowance; 4) to determine the relationship between adrenal gland morphometric and bruise severity on the carcass, at different space allowance. The study was conducted using 1,350 bulls (450 Nellore and 900 cross-bred Angus or Caracu x Nellore) raised on pasture and finished in a commercial feedlot. Temperament was assessed by the flight speed (FS) test on day 0 (FS0), 35 (FS35) and 87 (or last day; FSfin) of the feedlot period. Feedlot growth performances, carcass quality traits and meat pH24, adrenal gland morphometry and severity of bruises in carcasses were assessed. Flight speed decreased over time (p < 0.01) during the feedlot period. Overall FS neither differed between bulls kept at different space allowances (p = 0.79) nor between breeds (p = 0.16). The interaction between space allowance and breed or between FS0 and FSfin had no influence on any performance or carcass quality traits (p > 0.05). However, calm bulls according FSfin had greater average daily gain from day 0 to 35 (p < 0.0001), were heavier on the 35th (p < 0.0001) and on the 87th (p < 0.01) day in the feedlot and, consequently, produced heavier carcasses (p < 0.01) than intermediate and reactive ones, which did not differ between them. Regardless of space allowance or breed, reactive bulls according to FS0 had heavier adrenal glands (p < 0.01) and with greater perimeters (p = 0.01) when compared to the calm ones. Additionally, when kept in reduced space allowance (6 or 12 m2/animal) reactive bulls had greater cortical area (p < 0.05) than intermediate and calm ones. In relation to severity of bruises, bulls with higher medullar area, greater perimeter and heavier of adrenal glands (p < 0.05) kept at 6 or 24 m2/animal exhibited more severe bruising of the carcasses. We conclude that the feedlot conditions applied in this study improved bull temperament over time, and that, regardless of the space allowance provided to them and the breed, calm bulls showed better performances than intermediate and reactive ones. The animal ability to adapt to an intensive production system, such as feedlot, seems to contribute favorably to the quality of the production. The reduced space allowance in feedlots resulted in more detrimental effects on the welfare of reactive bulls than of the calm ones. Furthermore, it was clear that more stressed animals were more likely to have severe bruise on their carcasses.
The aim of this study was to evaluate the effects of bulls’ temperament kept at three different space allowances (6, 12, and 24 m2/animal) on growth performance, carcass traits, meat quality traits and animal welfare. The specific objectives were: 1) to evaluate the effects of space allowance on bulls’ temperament; 2) to evaluate the effects of temperament on growth performance, carcass and meat quality traits of beef cattle kept in different space allowance; 3) to evaluate the effects of temperament on adrenal gland morphometric and its relationship to space allowance; 4) to determine the relationship between adrenal gland morphometric and bruise severity on the carcass, at different space allowance. The study was conducted using 1,350 bulls (450 Nellore and 900 cross-bred Angus or Caracu x Nellore) raised on pasture and finished in a commercial feedlot. Temperament was assessed by the flight speed (FS) test on day 0 (FS0), 35 (FS35) and 87 (or last day; FSfin) of the feedlot period. Feedlot growth performances, carcass quality traits and meat pH24, adrenal gland morphometry and severity of bruises in carcasses were assessed. Flight speed decreased over time (p < 0.01) during the feedlot period. Overall FS neither differed between bulls kept at different space allowances (p = 0.79) nor between breeds (p = 0.16). The interaction between space allowance and breed or between FS0 and FSfin had no influence on any performance or carcass quality traits (p > 0.05). However, calm bulls according FSfin had greater average daily gain from day 0 to 35 (p < 0.0001), were heavier on the 35th (p < 0.0001) and on the 87th (p < 0.01) day in the feedlot and, consequently, produced heavier carcasses (p < 0.01) than intermediate and reactive ones, which did not differ between them. Regardless of space allowance or breed, reactive bulls according to FS0 had heavier adrenal glands (p < 0.01) and with greater perimeters (p = 0.01) when compared to the calm ones. Additionally, when kept in reduced space allowance (6 or 12 m2/animal) reactive bulls had greater cortical area (p < 0.05) than intermediate and calm ones. In relation to severity of bruises, bulls with higher medullar area, greater perimeter and heavier of adrenal glands (p < 0.05) kept at 6 or 24 m2/animal exhibited more severe bruising of the carcasses. We conclude that the feedlot conditions applied in this study improved bull temperament over time, and that, regardless of the space allowance provided to them and the breed, calm bulls showed better performances than intermediate and reactive ones. The animal ability to adapt to an intensive production system, such as feedlot, seems to contribute favorably to the quality of the production. The reduced space allowance in feedlots resulted in more detrimental effects on the welfare of reactive bulls than of the calm ones. Furthermore, it was clear that more stressed animals were more likely to have severe bruise on their carcasses.
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Palavras-chave
Ambiente, Confinamento, Velocidade de saída, Reatividade, Zebuínos, Environment, Feedlot, Flight speed, Reactivity, Zebu cattle