Long-term observations on relationship between food and water ingestion in the dog

Abstract

Studies of the food-water intake relationship were made on 18 dogs over a period of 7 years. Single observations proved to be without value because of the considerable day-by-day variations that occur despite controlled diet and environmental conditions. The mean of multiple successive observations results in data which are consistent for the same animal over periods of at least 3–4 years. Such data reveal a quantitative linear relationship between food and water intakes provided the composition of the diet is maintained constant. Alterations in this relationship readily occur as a result of alterations in either the salt or water content of food. When the water content of the diet is changed, drinking is accurately readjusted so that the total intake for a given amount of food remains constant. Food deprivation results in a prompt and marked drop in daily drinking, the latter however, gradually increasing as deprivation continues. The immediate and delayed factors that might be concerned in this food-water relationship are discussed.