Changes in total plasma protein, sodium and aldosterone concentration during milking, feeding, and food deprivation in the Swedish dairy cow
1995
Dahlborn, K. (Sveriges Lantbruksuniv., Uppsala (Sweden). Inst. foer Djurfysiologi) | Samuelsson, B. | Svennersten-Sjaunja, K.
Four nonpregnant, Swedish Red and White dairy cows were exposed to two different management treatments. The aim of the study was to investigate if lactating dairy cows react similar to feeding and food deprivation as small ruminants. In one treatment the cows were milked and fed simultaneously, and in the other treatment the cows were fed and milked separately. Then the cows were studied during 58 h food deprivation, followed by two days of recovery. During feeding both total plasma proteins (TPP) and plasma sodium increased. Aldosterone increased only when the cows were fed and milked simultaneously. There were no alterations in TPP or plasma sodium concentration during food deprivation. During refeeding in the morning on the first recovery day, when only a small amount of hay was fed, both TPP and plasma sodium concentration increased. Plasma aldosterone decreased during food deprivation and remained low at the first feeding occasion. During the second day of recovery plasma sodium was still elevated, but TPP and aldosterone had returned to basal levels. The faecal sodium content increased step wise during the food deprivation period. Food deprivation decreased water intake with 70%, and milk production with 65%.
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