Safwate A, Davicco M J, Barlet J P, Delost P
Reprod Nutr Dev (1980). 1981;21(4):601-10. doi: 10.1051/rnd:19810412.
Plasma sodium, potassium and aldosterone levels, daily milk production and milk sodium and potassium were measured in 10 Holstein X Friesian cows during a whole lactation period beginning in November and ending in November the following year. The milk production (4 p. 100 fat content) of these animals was 6 170 +/- 66 kg (mean +/- SEM). During the whole experimental period, the cows had free access to salt blocks and were thus always sodium-replete. Plasma sodium and potassium levels showed no significant variations during lactation. The daily excretion of sodium and potassium through milk paralleled that of daily milk production. Plasma aldosterone levels decreased sharply from 77.4 +/- 4.0 pg.ml-1 at calving to 13.2 +/- 3.6 pg.ml-1 (P less than 0.01) on day 7 of lactation, then remained stable until day 50 (16.4 +/- 4 pg.ml-1). They increased slightly on day 155 (60 days after mating: 36 +/- 5 pg.ml-1; P less than 0.05) and abruptly after spring grazing (54.9 +/- 11 pg.ml-1; P less than 0.01), then remained high until the end of lactation (48.5 +/- 12 pg.ml-1). Plasma aldosterone levels were 11.9 +/- 2.4 pg.ml-1 in seven 24-month old, non-pregnant heifers fed the same winter ration as the cows. No relationship could be demonstrated between sodium and potassium concentrations in blood and milk or between those parameters and plasma aldosterone levels. Thus, in high-yield dairy cows, aldosterone does not seem to play a major role in the regulation of sodium and potassium excretion through milk.
在11月开始至次年11月结束的整个泌乳期内，对10头荷斯坦×弗里生奶牛的血浆钠、钾和醛固酮水平、日产奶量以及奶中的钠和钾含量进行了测定。这些奶牛的产奶量（含4%脂肪）为6170±66千克（均值±标准误）。在整个实验期间，奶牛可以自由采食盐块，因此始终处于钠充足状态。泌乳期间血浆钠和钾水平无显著变化。通过牛奶排出的钠和钾的日排泄量与日产奶量平行。血浆醛固酮水平在产犊时从77.4±4.0皮克/毫升急剧下降至泌乳第7天的13.2±3.6皮克/毫升（P<0.01），然后在第50天之前保持稳定（16.4±4皮克/毫升）。在第155天（配种后60天）略有升高（36±5皮克/毫升；P<0.05），春季放牧后突然升高（54.9±11皮克/毫升；P<0.01），然后在泌乳结束前一直保持较高水平（48.5±12皮克/毫升）。7头24月龄、未怀孕且与奶牛采食相同冬季日粮的小母牛的血浆醛固酮水平为11.9±2.4皮克/毫升。血液和牛奶中的钠和钾浓度之间，以及这些参数与血浆醛固酮水平之间均未显示出相关性。因此，在高产奶牛中，醛固酮似乎在通过牛奶调节钠和钾排泄方面不起主要作用。
