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Abstract

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 degrees 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.

Keywords

cortisol; goat; heat stress; lactation; osmolality; pregnancy; urine flow; water intake

Published in

Comparative Biochemistry and Physiology - Part A: Physiology
1996, volume: 113, number: 4, pages: 323-331
Publisher: PERGAMON-ELSEVIER SCIENCE LTD

SLU Authors

  • Olsson, Kerstin

    • Department of Animal Physiology, Swedish University of Agricultural Sciences

  • Cvek, Katarina

    • Department of Animal Physiology, Swedish University of Agricultural Sciences

  • Sandberg, Eva

    • Department of Animal Physiology, Swedish University of Agricultural Sciences

  • Dahlborn, Kristina

    • Department of Animal Physiology, Swedish University of Agricultural Sciences

UKÄ Subject classification

Biochemistry
Molecular Biology
Clinical Science

Publication identifier

  • DOI: https://doi.org/10.1016/0300-9629(95)02072-1

Permanent link to this page (URI)

https://res.slu.se/id/publ/95596