Harris P A, Marlin D J, Scott C M, Harris R C, Mills P C, Michell A R, Orme C E, Roberts C A, Schroter R C, Marr C M
Physiology Unit, Animal Health Trust, Newmarket, Suffolk, UK.
Equine Vet J Suppl. 1995 Nov(20):85-96.
Four horses (H, J, N and M) undertook a simulated competition exercise test (CET), designed to simulate physiological and metabolic stresses of the Speed and Endurance (S & E) test of a 3-day-event, under 3 different environmental conditions: 20 degrees C/40% relative humidity (RH) (cool, dry [CD] 2 sessions); 30 degrees C/40% RH (hot, dry [HD]) and 30 degrees C/80% RH (hot, humid [HH]) (Marlin et al. 1995a). Venous blood samples for electrolyte and total protein (TP) determinations were collected from indwelling catheters at predetermined time points throughout each CET and initial 30 min recovery period. Venous blood samples were collected by jugular venepuncture at 2 h and 24 h after the end of the final 8 min canter (Phase D). The effects of exercise, environmental condition and horse on venous TP, sodium (Na+), potassium (K+), chloride (Cl-), calcium (Ca2+), magnesium (Mg2+) and phosphate (PO4(3-)) plasma concentrations were investigated. In addition, the effect of environmental condition on estimated cation loss was evaluated. All horses completed the full CET under the CD and HD conditions, but only one horse completed the full 8 min of the final canter Phase D under HH conditions. Exercise had a significant (P < 0.05) effect on all parameters similar to those reported previously in field competitions. There was a significant (P < 0.05) interaction between time and horse for TP, Na+ and Cl-. Overall, the environmental condition had a significant (P < 0.05) effect on all parameters, but the differences were not considered to be of any physiological relevance, other than for Cl- and TP. There was a significant (P < 0.05) interaction between time and environmental condition for Cl- and TP only. During much of the CET and recovery period, mean Cl- values were higher with the first CD session than the second CD session or under the HH or HD conditions. For TP after 2 min of Phase D and during the initial recovery period, concentrations were higher under the HH conditions and returned to the Pre- values less quickly. There were marked individual variations in the estimated cation losses and no consistent effect of environmental condition was found. Although estimated fluid loss was similar following both HD and HH sessions, restoration of bodyweight was slower following the CET studies under HH conditions.
四匹马（H、J、N和M）进行了一项模拟竞赛运动测试（CET），该测试旨在模拟三日赛速度与耐力（S&E）测试中的生理和代谢应激，测试在三种不同环境条件下进行：20摄氏度/40%相对湿度（RH）（凉爽、干燥[CD]，共2个时段）；30摄氏度/40%RH（炎热、干燥[HD]）和30摄氏度/80%RH（炎热、潮湿[HH]）（马林等人，1995a）。在每个CET的预定时间点以及最初30分钟的恢复期，从留置导管采集静脉血样，用于测定电解质和总蛋白（TP）。在最后8分钟慢跑（D阶段）结束后的2小时和24小时，通过颈静脉穿刺采集静脉血样。研究了运动、环境条件和马匹对静脉血TP、钠（Na+）、钾（K+）、氯（Cl-）、钙（Ca2+）、镁（Mg2+）和磷酸盐（PO4(3-)）血浆浓度的影响。此外还评估了环境条件对估计阳离子损失的影响。所有马匹在CD和HD条件下均完成了完整的CET，但在HH条件下，只有一匹马完成了最后8分钟慢跑D阶段的全程。运动对所有参数均有显著（P<0.05）影响，与先前在野外比赛中报道的情况类似。TP、Na+和Cl-在时间和马匹之间存在显著（P<0.05）交互作用。总体而言，环境条件对所有参数均有显著（P<0.05）影响，但除了Cl-和TP外，这些差异被认为没有任何生理相关性。仅Cl-和TP在时间和环境条件之间存在显著（P<0.05）交互作用。在CET和恢复期的大部分时间里，第一个CD时段的平均Cl-值高于第二个CD时段或HH或HD条件下的Cl-值。对于D阶段2分钟后和最初恢复期的TP，HH条件下的浓度更高，且恢复到初始值的速度较慢。估计阳离子损失存在明显的个体差异，未发现环境条件有一致的影响。尽管HD和HH时段后的估计液体损失相似，但在HH条件下进行CET研究后，体重恢复较慢。
