University of Arkansas, Fayetteville Division of Agriculture


Crossbred barrows and gilts (n = 36), weighing 16.59 ± 2.1 kg, were used to test the effects of stressing a pen mate on the physiological responses of growing pigs. Pigs were randomly allotted to 6 groups after stratifying according to gender, litter origin, and body weight. Dominance order was determined within each group, and 1 to 3 d prior to the stress treatment the most- and leastdominant pigs within a group were fitted with indwelling catheters in their vena cavas. Over 3 d, groups were either: 1) isolated from audile and visual contact with stressed pigs in a separate room (non-stressed control); 2) separated by a curtain from visual contact with stressed pigs; or 3) allowed to maintain audile and visual contact with stressed pigs. Blood samples were collected 30, 15, and 0 min before exposure to the stressor (snout-snare) treatment and again at 1, 2, 3, 4, 5, 7.5, 10, 15, 20, 25, and 30 min after stressor application. Serum cortisol and plasma glucose, lactate, and nonesterified fatty acids (NEFA) concentrations were measured. There were no treatment × sampling-time interactions (P > 0.17) for concentrations of cortisol, glucose, lactate or NEFA, nor were these metabolites affected by stressor treatment (P > 0.42). Humoral measures of the stress response were not affected by visual and/or audile contact with pen mates undergoing a stressful event.