Maintenance energy of buffaloes in different environmental temperatures.

将3头水牛和3头荷斯坦奶牛在气候化实验室（Zootron，NIAI）中恒温30 ℃（60%RH，12 L/12 D）饲养7 d，每隔3 h饲喂一次（恒温条件）。然后在13 EA-12 D（平均30 ℃，60%RH，12 L，12 D，波动条件），25 ~ 35 ℃的室内禁食5d。在波动条件下，水牛产热显著低于荷斯坦牛。而在恒温条件下，两种植物的s13 EA含量无显著差异。当气温从25 ℃（0：00）升高到35 ℃（12：00）时，荷斯坦牛的呼吸速率、呼吸量和产热率几乎都随着气温的升高而增加，而直肠温度几乎不变。而水牛的呼吸频率、呼吸量和产热在6 h内没有增加，直肠温度随气温的升高而升高。这些结果表明，水牛维持在一个相当低的呼吸水平，通过储存热量在他们的身体质量，当空气温度上升在早晨。水牛13 EA的这种热不稳定性可能有助于这种动物在昼夜气温变化过程中抑制呼吸运动的节能特性。

Three buffalo-cows and three Holstein cows were maintained in a climatized laboratory(Zootron, NIAI) for 7days at constant temperature of 30ﾟC(60%RH,12L12D) and fed every 3hours(constant condition). Then, they were fasted for 5days in the room where13EA\ : the air temperature fluctuated diurnally between 25 and 35ﾟC(average 30ﾟC, 60%RH, 12L12D, fluctuating condition). Under the fluctuating condition, heat productions in buffaloes were significantly lower than those in Holsteins. On the contraly, no s13EA\ : ignificant difference was observed between the two species in the constant temperature. when air temperature increased from 25ﾟC(0 : 00) to 35ﾟC(12 : 00), the respiration rate, respiratory volume and heat production in Holsteins increased almost sim13EA\ : ultaneously, while the rectal temperature in this species was almost constant. In the other hand, respiration rate, respiratory volume and heat production in buffaloes did not increased first 6hours, duing which rectal temperature increased associat13EA\ : ed with the increase of air temperature. These results indicate that buffaloes maintain their respiration at a fairly low level by storing heat within their body mass when the air temperature increases in the morning. This thermolability in buffaloe13EA\ : s may contribute to the energy saving characteristics of this animal by refraining the respiratory exercise in the course of diurnal changes of air temperature.