Olsson K, Josäter-Hermelin M, Hossaini-Hilali J, Cvek K, Hydbring E, Dahlborn K
Department of Animal Physiology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Comp Biochem Physiol A Physiol. 1996 Apr;113(4):323-31. doi: 10.1016/0300-9629(95)02072-1.
Water intake following dehydration was studied in pregnant (N = 5), lactating (N = 4) and nonpregnant, nonlactating (N = 5) Swedish domestic goats (Capra hircus) to investigate if reproductive period affected drinking. Plasma cortisol concentration and the hematocrit value were measured to evaluate stress. The goats were water deprived from 9.00 h until 15.05 h the next day. They were fed at 7.00 and 15.20 h. On the second day, ambient temperature was increased from 20 degrees C to 38-39.5 degrees C for 5.15 h to accelerate water losses. Water temperature during rehydration was 35 +/- 1 degree C. Plasma Na concentration and osmolality increased most in dehydrated and heat-stressed pregnant and lactating goats. Pregnant goats lost 2.2 kg of their body weight. They drank 3.5 l immediately, followed by 2.5 l during afternoon eating. Lactating goats lost 4.9 kg and drank 6.3 l at once, and 3.9 l during feeding. Nonpregnant, nonlactating goats lost 1.7 kg and drank 2.6 l followed by 0.6 l. The large water consumption in pregnant and lactating goats caused hyponatremia and hemodilution, but they continued to drink during the night (0.5 +/- 0.2 l and 0.8 +/- 0.5 l, respectively). Renal free water clearance increased in all periods, with a long-lasting water diuresis during pregnancy. Plasma cortisol concentrations and the hematocrit values rose in connection with water intake. These results imply that the thirst center became less sensitive to inhibitory signals from the oropharyngeal tract and the diluted blood plasma during pregnancy and lactation. Catching sight of water was the most exciting procedure during these experiments.
对怀孕（N = 5）、泌乳（N = 4）以及未怀孕、未泌乳（N = 5）的瑞典家养山羊（Capra hircus）进行了脱水后饮水情况的研究，以调查繁殖期是否会影响饮水。测量了血浆皮质醇浓度和血细胞比容值以评估应激情况。山羊从上午9点开始禁水，直到第二天15:05。它们在7点和15:20进食。第二天，环境温度从20摄氏度升高到38 - 39.5摄氏度，持续5.15小时以加速水分流失。补液期间水温为35±1摄氏度。脱水且受热应激的怀孕和泌乳山羊的血浆钠浓度和渗透压升高最为明显。怀孕山羊体重减轻了2.2千克。它们立即饮用了3.5升水，下午进食期间又饮用了2.5升。泌乳山羊体重减轻了4.9千克，一次饮用了6.3升水，进食期间饮用了3.9升。未怀孕、未泌乳的山羊体重减轻了1.7千克，饮用了2.6升水，随后又饮用了0.6升。怀孕和泌乳山羊大量饮水导致低钠血症和血液稀释，但它们在夜间仍继续饮水（分别为0.5±0.2升和0.8±0.5升）。所有时期肾自由水清除率均增加，怀孕期间出现持久的水利尿。血浆皮质醇浓度和血细胞比容值随饮水而升高。这些结果表明，在怀孕和泌乳期间，口渴中枢对口咽道和稀释血浆的抑制信号变得不那么敏感。在这些实验中，看到水是最令人兴奋的过程。
