Effects of conditioning and maximal incremental exercise on oxygen consumption in sheep
Mundie, T.G.; Januszkiewicz, A.J.; Rayburn, D.B.; Martin, D.G.; Ripple, G.R.
American Journal of Veterinary Research 52(7): 1019-1023
1991
ISSN/ISBN: 0002-9645 PMID: 1892256 Document Number: 384143
To assess the suitability of sheep of exercise studies, the effect of incremental exercise and conditioning on oxygen consumption (.ovrhdot.VO2) was studied. Six sheep were adapted to a treadmill and subsequently trained 8 weeks. The sheep were then studied, in random order, using 3 incremental exercise protocols (EX-1, EX-2, and EX-3). The protocols were chosen to approximate high (EX-1), moderate (EX-2), and low (EX-3) intensity exercise by varying treadmill speed and incline. The sheep were then conditioned for an additional 12 weeks and retested on the EX-2 protocol. During exercise, .ovrhdot.VO2, gas exchange ratio (R), and rectal temperatures (Tb) were recorded. All 3 protocols resulted in significantly increases in .ovrhdot.VO2, R, and Tb, (P < 0.05). Maximum .ovrhdot.VO2 for EX-1, 49.9 .+-. 5.0 ml/min/kg of body weight, was significantly greater than maximum .ovrhdot.VO2 for EX-2 and EX-3, 37.8 .+-. 6.5 and 42.3 .+-. 6.0 ml/min/kg, respectively (P < 0.05), whereas maximum R and maximum Tb were similar. After the additional 12-week conditioning, time on the treadmill increased 40% from 9.58 .+-. 0.87 to 13.4 .+-. 0.44 minutes, and maximum .ovrhdot.VO2 increased 27% to 48.1 .+-. 9.1 ml/.min/kg. These data indicated that maximum .ovrhdot.VO2 varied with intensity of the exercise, 12 weeks of maximal exercise conditioning was sufficient to produce a measurable training effect (i.e., increase endurance and maximum oxygen consumption) and sheep are suitable for maximal exercise studies where .ovrhdot.VO2 measurements are desirbed.