Influence of treadmill exercise on pitutary-adrenal secretions, other blood constituents, and meat quality of sheep

Wether lambs were used to evaluate the influence of treadmill exercise (TME) on physiological responses and meat quality. Lambs were exercised at either 5.6, 7.2, or 8.8 km/h on a 9 degree incline for 10 min, followed by a 10-min walk at 4.0 km/h and 0 degree incline, or were unexercised controls (C; n = 3/treatment). Heart rates were determined at -15, 1, 3, 6, 10, and 15 min relative to the onset of exercise. Blood was collected at 2.5-min intervals during and after exercise for determination of plasma concentrations of ACTH, cortisol, and lactate. In addition, blood collected during exercise was evaluated for hematocrit and for concentrations of glucose, hemoglobin, and total protein. Exercised lambs had greater (P < 0.01) heart rates than C lambs during and after exercise. Blood from TME lambs also had greater (P < 0.001) hematocrit percentages, total protein, and hemoglobin concentrations. Areas under the ACTH and cortisol response curves were greater (P 0.05) by TME. Treadmill exercise caused dramatic changes in blood constituents but had minimal influences on meat quality.