Estimating body water content in live animal using Antipyrine substance as a new and modified technique was the objective of this research. Body water was estimated in five calves with average body weight of 183.6 ± 30.3 kg using conventional method (extrapolation technique) and in the same time by modified method. The averages of total body water in five calves were 135.8 ± 11.8 and 132.3 ± 11.35 liters by convention and modified technique, respectively, without significant difference between the two techniques. The corresponding summations of body water in all calves were 679.2 and 661.4 liters. The accuracy of modified technique was 97.4 % as compared with convention method.
It is concluded that estimate body water using Antipyrine by new method is easily, accurate and quickly technique and more reliable. Animals when exposed to high ambient temperature during hot summer season, water intake increase and consequently body water content increases with different percentage according animal response to stressful conditions. The percentage change in body water or body solids (Live body weight- body water) contents in each animal may be used for evaluation the animal's adaptability to heat stress.