INFLUENCE OF TREADMILL EXERCISE ON PITUITARY-ADRENAL SECRETIONS OTHERBLOOD-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 exercis ed at either 5.6, 7.2, or 8.8 km/h on a 9 degrees incline for 10 min, followed by a 10-min walk at 4.0 km/h and 0 degrees incline, or were u nexercised controls (C; n = 3/treatment). Heart rates were determined at -15, 1, 3, 6, 10, and 15 min relative to the onset of exercise. Blo od was collected at 2.5-min intervals during and after exercise for de termination of plasma concentrations of ACTH, cortisol, and lactate. I n addition, blood collected during exercise was evaluated for hematocr it and for concentrations of glucose, hemoglobin, and total protein. E xercised lambs had greater (P < .01) heart rates than C lambs during a nd after exercise. Blood from TME lambs also had greater (P < .001) he matocrit percentages, total protein, and hemoglobin concentrations. Ar eas under the ACTH and cortisol response curves were greater(P < .001) for TME than for C lambs. Areas under glucose response curves were gr eater for all TME treatments (P < .001) than for C and greater(P < .00 1) for lambs exercised at 8.8 km/h than for lambs exercised at 5.6 km/ h. Areas beneath lactate response curves were greater (P < .001) for l ambs exercised at 8.8 km/h than for lambs exercised at 7.2 km/h and C lambs. Carcasses from lambs exercised at 5.6 km/h had lesser(P < .05) longissimus muscle (LM) glycogen concentrations at slaughter than carc asses from lambs exercised at either 7.2 or 8.8 km/h and C lambs. At 4 8 h postmortem, LM pH and color were unaffected (P > .05) by TME. Trea dmill exercise caused dramatic changes in blood constituents but had m inimal influences on meat quality.