Department of Animal Science, Federal Rural University of the Semi-arid Region (UFERSA), 59625-900, Mossoró, RN, Brazil.
Department of Animal Science, State University of Valley Acaraú (UVA), 62040-370, Sobral, CE, Brazil.
J Therm Biol. 2020 May;90:102593. doi: 10.1016/j.jtherbio.2020.102593. Epub 2020 Apr 14.
The objective of this study was to evaluate the thermoregulatory responses, acid-basic and electrolytic equilibrium of locally adapted goats under natural heat conditions in a semi-arid region. Ten (10) Canindé goats aged between 2 and 3 years, non-lactating, non-pregnant and having a body weight (B) of 22.90 ± 2.70 kg were used in this study. Air temperature (A) and relative humidity (R) were measured, and the radiant heat load (RHL) was subsequently calculated. Rectal temperature (R), respiratory rate (R), sweating rate (S) and heat shock (S) were recorded at 1-h intervals for 24 continuous hours. Hydrogen potential (pH), partial pressure of carbon dioxide (PCO), partial pressure of oxygen (PO), bicarbonate (HCO), base excess (BE), total carbon dioxide concentration (TCO), oxygen saturation (SO), sodium (Na) and potassium (K) were recorded at three moments during the day (5 a.m.; 1 p.m.; 6 p.m.). There were also significant differences between the means of hours of the day for A and R. R was the thermoregulatory response which most closely followed RHL, with important elevations in the periods between 10 a.m. to noon. It was observed that the goats activated their SR mechanism before R, more precisely between the hours of 9 a.m. and 1 p.m. The acid-base and electrolytic equilibrium for the goats which showed great association with the first components contributed the most to the total variation of the data. The most important variables in the adaptive profile of these animals in order of importance were: SO, PO, R, R, S, HCO, BE, TCO and pH. An association between all variables grouped in each period was observed, where the thermoregulatory responses in the periods of 5 a.m. and 6 p.m. were closer than when compared to 1 p.m., showing a physiological return to the initial state. Therefore, the variation in thermoregulatory responses, acid-base and electrolytic equilibrium indicated that the goats have the ability to recover after a challenging environmental condition.
本研究旨在评估在半干旱地区自然热条件下，适应本地环境的山羊的体温调节反应、酸碱和电解质平衡。本研究使用了 10 只 2-3 岁、非哺乳期、非妊娠、体重（B）为 22.90±2.70kg 的 Canindé 山羊。测量空气温度（A）和相对湿度（R），并随后计算辐射热负荷（RHL）。记录 24 小时内每小时 1 次的直肠温度（R）、呼吸频率（R）、出汗率（S）和热休克（S）。在一天中的三个时间点（上午 5 点；下午 1 点；下午 6 点）记录氢电势（pH）、二氧化碳分压（PCO）、氧分压（PO）、碳酸氢盐（HCO）、碱剩余（BE）、总二氧化碳浓度（TCO）、氧饱和度（SO）、钠（Na）和钾（K）。A 和 R 的日小时平均值之间也存在显著差异。R 是与 RHL 最密切相关的体温调节反应，在上午 10 点至中午之间的时间段内有重要的升高。观察到山羊在 R 之前激活了它们的 SR 机制，更准确地说，是在上午 9 点至下午 1 点之间。山羊的酸碱和电解质平衡与第一个成分有很大的关联，对数据的总变异贡献最大。这些动物适应特征的最重要变量按重要性顺序排列为：SO、PO、R、R、S、HCO、BE、TCO 和 pH。观察到每个时间段内所有变量的分组之间存在关联，其中上午 5 点和下午 6 点的体温调节反应比下午 1 点更接近，表现出生理上回归到初始状态。因此，体温调节反应、酸碱和电解质平衡的变化表明，山羊在经历具有挑战性的环境条件后有能力恢复。
