Human-animal interactions at abattoirs: Relationships between handling and animal stress in sheep and cattle

Relationships between handling and animal stress were studied in 200 animals, of similar age from one property, at each of two sheep and two cattle abattoirs (n = 800). A total of 14 and 13 stockpeople handled the study sheep and cattle, respectively. At each abattoir, 10 cohorts of 20 animals from the 200 study animals were individually moved from the forcing pen to the stunning area and the frequency of tactile, auditory and visual interactions used by stockpeople was recorded. The use of dogs on each sheep was scored based on duration and intensity of dog use. The head position of each sheep and cattle, head down or head up, was scored in response to both a stockperson handling the animals and a stationary observer located just prior to the stunning area. The frequency of vocalizations by sheep and cattle at the end of the single file race was also recorded. Animals were slaughtered by ventral-neck incision after stunning and blood samples for cortisol analysis were collected from all study animals within 1 min of the ventral-neck incision. Cortisol concentrations were correlated with many of the behavioural variables studied. The regression model that best predicted cortisol concentrations in sheep post-slaughter included the variables: cohort, head position of the animal, dog use score, and the frequency of touches and pushes and the frequency of whistles by stockpeople to handle the animal. This model accounted for 42% of the variance in cortisol concentrations of sheep (adjusted R-2 = 0.42, P = 0.001). The regression model that best predicted cortisol concentrations in cattle post-slaughter included the variables: abattoir, head position of the animal, cohort, and frequency of goad use by stockpeople to move the animal. This model accounted for about 19% of the variance in cortisol concentrations of cattle (adjusted R-2 = 0.19, P = 0.001). The direction of the relationships indicate that increased head down by sheep, increased dog use and fewer whistles, and fewer touches and pushes by stockpeople were associated with increased cortisol concentrations in sheep, while increased head down by cattle, increased vocalizations by cattle and increased goad use by stockpeople were associated with increased cortisol concentrations in cattle. The identification of these predictor variables of cortisol, which may be a mixture of independent and mediating variables, support the well-demonstrated effect of handling on fear and stress responses in livestock. Furthermore, these relationships, although not conclusive evidence of causal relationships, indicate the possibility of training stockpeople to reduce fear and stress in livestock at abattoirs. (C) 2011 Elsevier B.V. All rights reserved.