Olsson K, Benlamlih S, Dahlborn K, Fyhrquist F
Acta Physiol Scand. 1982 Jul;115(3):361-7. doi: 10.1111/j.1748-1716.1982.tb07090.x.
The response to 30 h water deprivation was studied in 7 goats during the last month of pregnancy and during lactation with anestrus as the control period. Plasma osmolality and plasma Na concentration increased by about 4% in pregnant and lactating goats and by about 2% in anestral goats. Plasma AVP concentration rose by about 7 pg/ml in pregnant and lactating goats, but only by about 3 pg/ml during anestrus. PRA was elevated in pregnant animals, but dehydration caused only a minor further rise. Total plasma protein concentration was low in pregnant goats and did not increase during water deprivation, but it did so in lactating animals. Neither the hematocrit nor the plasma K concentration changed in response to dehydration. GFR fell by about 24% in pregnant goats and by 22% in lactating animals, but remained unchanged during anestrus. ERPF fell by 20% in lactating animals, but no consistent effect of the dehydration was seen during pregnancy and anestrus. Urine flow decreased by about 75% during pregnancy, 55% during lactation and 65% during anestrus with the highest urine osmolality observed during anestrus. Milk production was only slightly reduced, but the milk osmolality increased in parallel with that of the blood plasma. When allowed to drink at the end of the water deprivation period, pregnant goats immediately drank 2.5 +/- 0.5 litres, lactating goats 3.3 +/- 0.9 litres and anestral goats 1.1 +/- 0.3 litres. When hyperhydrated, pregnant goats excreted the excessive water more readily and showed less response to exogenous AVP than lactating and anestral animals. In conclusion, pregnant and lactating goats are obviously more susceptible to a shortage of water supply than anestral animals but can easily excrete an excess of water.
在妊娠最后一个月以及泌乳期的7只山羊中研究了对30小时禁水的反应，并以乏情期作为对照期。妊娠和泌乳山羊的血浆渗透压和血浆钠浓度升高约4%，而乏情期山羊升高约2%。妊娠和泌乳山羊的血浆血管加压素（AVP）浓度升高约7 pg/ml，但在乏情期仅升高约3 pg/ml。妊娠动物的肾素活性（PRA）升高，但脱水仅使其略有进一步升高。妊娠山羊的血浆总蛋白浓度较低，禁水期间未升高，但泌乳动物则升高。红细胞压积和血浆钾浓度均未因脱水而改变。妊娠山羊的肾小球滤过率（GFR）下降约24%，泌乳动物下降22%，但在乏情期保持不变。泌乳动物的有效肾血浆流量（ERPF）下降20%，但在妊娠和乏情期未观察到脱水的一致影响。妊娠期间尿流量减少约75%，泌乳期减少55%，乏情期减少65%，乏情期观察到最高尿渗透压。产奶量仅略有减少，但乳渗透压与血浆渗透压平行升高。在禁水期结束允许饮水时，妊娠山羊立即饮水2.5±0.5升，泌乳山羊饮水3.3±0.9升，乏情期山羊饮水1.1±0.3升。当水合过多时，妊娠山羊比泌乳和乏情期动物更易排出过多水分，且对外源性AVP的反应较小。总之，妊娠和泌乳山羊显然比乏情期动物更容易受到供水短缺的影响，但能够轻松排出多余的水分。
