Implicações do manejo de desmame no desempenho, saúde e bem-estar de bezerros nelore, puros e cruzados (Aberdeen Angus x Nelore)
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Data
2022-07-14
Autores
Ruiz, Lucas Roberto Batista
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Universidade Estadual Paulista (Unesp)
Resumo
. O manejo de desmame é reconhecidamente estressante para vacas e bezerros, com consequentes prejuízos ao bem-estar e ao desempenho dos animais. O objetivo com a realização deste estudo foi comparar os efeitos de curto prazo no ganho de peso de bezerros da raça Nelore submetidos ao desmame abrupto com vacas madrinhas (AB) e desmame lado a lado (LL). O estudo foi realizado em uma fazenda comercial, localizada no município de Poxoréu-MT, Brasil, durante os meses de maio a agosto. Foram avaliados 80 bezerros da raça Nelore, sendo 40 fêmeas e 40 machos, desmamados com aproximadamente oito meses de idade. Os bezerros foram pesados, no dia do desmame (D0) e dez (D10), trinta (D30), cinquenta e dois (D52) e oitenta e cinco dias (D85) após o desmame. Os ganhos de peso médios diários (GMDs) foram calculados para os quatro períodos de avaliação (de D0 a D10, D0 a D30, D0 a D52 e D0 a D85). As médias ajustadas para peso e ganho de peso foram comparadas utilizando o teste de Tukey considerando P ≤ 0,05 como efeito significativo e 0,051 < P > 0,10, como tendência. O peso inicial dos bezerros (D0) não diferiu significativamente entre os tratamentos (P = 0,165), com valores de 200,11Kg ± 0,97 e 198,16Kg ± 0,98 para LL e AB, respectivamente. Houve efeito significativo para interação dia de pesagem e ganho de peso dos bezerros (P = 0,001), sendo que os maiores ganhos de peso se concentram nos dias mais próximos do desmame para ambos métodos de desmame, reduzindo ao longo do tempo. Os bezerros do grupo LL apresentaram GMD superior ao grupo AB aos 10 e 30 dias pós desmame, apresentando a diferença de 350 e 110g/dia, respectivamente. Assim, conclui-se que adesmama lado a lado resulta em melhor desempenho dos bezerros.
This case report aims to describe the occurrence of negative impacts of wearing nose-flap devices on beef calves subjected to the two-stage weaning method. Forty-one calves, twenty-one pure Nellore and twenty F1 Angus-Nellore, were weaned on average at 236 days of age. Commercial nose-flap devices were fitted in the nostrils of the calves (d0) to prevent suckling and removed five days later (d5). Individual body weights were assessed at d0 and d5, and average daily gain (ADG) was calculated. At d5, during nose-flap device removal, it was noted that 26.8% of the calves lost the nose-flap device; however, all of them had wounds in their nostrils (no injuries in the nostrils had been observed on d0). To assess the severity of these injuries, an impairment score was assigned to each calf, ranging from 1 = no lesions to 5 = injured with purulent discharge. A logistic regression model was fitted to evaluate the effect of sex and genetic group on nose-flap retention (kept or lost). The retention rate did not differ (p > 0.05) between sex and genetic groups. All calves showed at least open wounds of the nasal septum (score 2), including those that lost the nose-flaps before d5. Almost half of the calves showed weight loss during this period. We conclude that there is a considerable risk of the two-stage weaning method compromising the physical integrity of the nostrils of beef calves through the use of these devices, and due to this, it should not be referred to as a low-stress weaning practice for beef calves.
This case report aims to describe the occurrence of negative impacts of wearing nose-flap devices on beef calves subjected to the two-stage weaning method. Forty-one calves, twenty-one pure Nellore and twenty F1 Angus-Nellore, were weaned on average at 236 days of age. Commercial nose-flap devices were fitted in the nostrils of the calves (d0) to prevent suckling and removed five days later (d5). Individual body weights were assessed at d0 and d5, and average daily gain (ADG) was calculated. At d5, during nose-flap device removal, it was noted that 26.8% of the calves lost the nose-flap device; however, all of them had wounds in their nostrils (no injuries in the nostrils had been observed on d0). To assess the severity of these injuries, an impairment score was assigned to each calf, ranging from 1 = no lesions to 5 = injured with purulent discharge. A logistic regression model was fitted to evaluate the effect of sex and genetic group on nose-flap retention (kept or lost). The retention rate did not differ (p > 0.05) between sex and genetic groups. All calves showed at least open wounds of the nasal septum (score 2), including those that lost the nose-flaps before d5. Almost half of the calves showed weight loss during this period. We conclude that there is a considerable risk of the two-stage weaning method compromising the physical integrity of the nostrils of beef calves through the use of these devices, and due to this, it should not be referred to as a low-stress weaning practice for beef calves.
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Bem-estar Animal, Animal welfare, Bovinos, Bezerros