M. L. P. Lima, J. A. Negrao, C. C. P. Paz, T. Grandin
Most traditional corral facilities are designed and built without the use of animal welfare principles, and can cause stress and fear reactions. This experiment was conducted to evaluate the influence of modifications to transform traditional corral into humane livestock handling system in cattle behavior and serum cortisol. The corral modifications consisted of blocking vision when the worker stands inside the animal’s flight zone, eliminating contrast of light and dark or shadows, and keeping the workers calm, not allowing them to scream or hit the animals during handling. Electric cattle prods were not permitted. A total of 382 Nellore steers, from 12 to 20 mo of age, from five different ranches were studied. First, the behavior of the animals in a traditional corral was evaluated. After corral modification and changing for calm handling procedures, the same animals returned (6 d later) for a second behavioral assessment. During restraining, before and after corral modifications, blood samples were collected from the jugular vein for analysis of serum cortisol. The cattle were evaluated using visual scores. Entry behavior (EB) into the restraint device was evaluated by observing whether the bovines walked, trotted, or ran. Chute temperament (CT) was assessed by considering whether the animal was very calm, calm, agitated, very agitated, or struggling to escape; and exit gait (EX) by observing whether the animal walked, trotted, or ran. After corral modification, cattle exhibited lower EB (P < 0.0001) and EX (P < 0.0001) and a higher proportion of animals was calm (CT-P < 0.0001) during restraining. The proportion of cattle that walked, trotted or ran was, respectively, 61.9, 30.4, and 7.7% for EB and 47.9, 36.9, and 13.4% for EX before corral modification, and 79.3, 16.8, and 3.9% for EB and 74.0, 19.7, and 6.3% for EX after corral modification. For CT, the proportion of very calm, calm, agitated, very agitated, and struggling to escape animals was 26.8, 36.6, 23.4, 12.1, and 4.2% before corral modification, and 48.1, 32.1, 15.1, 3.6, and 1.1% after corral modification, respectively. Serum cortisol levels were significantly lower (P < 0.0001) after corral modification. Mean serum cortisol was 47.87 mg/dL before corral modification and 32.49 mg/dL after corral modification. Good handling practices, corral reconstruction, blocking vision in specifics areas, and respecting the natural movement can reduce stress in cattle.
Fonte: Journal of Animal Science, v.94, p.31-32, 2016. Supplement, 5.
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