Studies on experimental water intoxication in calves

Abstract

water intoxication is a disease that affects all domestic livestock species but most commonly reported in calves. The aims of this study were to reproduce the disease in calves under experimental conditions and to evaluate clinicopathologic changes that occur in the course of the disease. A total of ten two-week old calves, five in the test group and five in the control group were used. Both groups were raised in identical managemental conditions except that in the test group, no water and salts were provided except that contained in the milk, in the whole preweaning period. After an acclimatization period of two weeks, body physiologic parameters were monitored, measurements being taken once per week. The measurements included heart and repiratory rates, and rectal temperature. Body weight was determined once every two weeks. Blood serum, whole blood, urine, and faecal samples were' collected once per week and laboratory analysis of packed cell volum~ (PCV) , red blood cell (RBC) count, white blood cell (WBC) count, total plasma proteins (TPP) , erythrocyte fragility, aspartate aminotransferase (AST) activity, blood urea nitrogen (BUN), Na+, K+, urine volume, % faecal water content, and urine specific gravity carried out. After the induction of water intoxication in the test group, the animals were monitored constantly and samples collected once per day. Two trials of induction were carried at an interval of one month and in each case, water was ingested voluntarily after provision ad libitum Water intoxication was observed in all the test calves with varying degrees of clinical manifestation. After the induction of the disease for the first time, 4 out of 5 animals showed all the signs of water intoxication with varying degrees of severity. After the re-induction of the disease, all the animals suffered from mild to severe form of the disease, and two of them died. There were drastic changes in most of the parameters investigated. Body weight, rectal temperature, and heart and respiratory rates responded by a decr,ease. PCV, RBC, WBC and Na+ also responded by a decrease while increases in TPP, erythrocyte fragility, AST, BUN, K+, and urine specific gravity were recorded. The results of this study were discussed on the basis of water metabolism in the body. These results suggested that water intoxication could be reproduced experimentally by restriction of both salt and water, and restriction of these two components were involved in pathogenesis of the disease in calves. The disease led to drastic changes in blood constituents and most of these were manifested in the clinical signs observed. from these study farmers are advised to provide both salts and water from as early as two weeks of age, and further study on water intoxication is recommended.