Modified Technique for Estimating Total Body Water in Live Animals Using Antipyrine Substance for Measuring Thermal Tolerances

Abstract

Estimating the total body water (TBW) in the live animals using the antipyrine substance as a modified technique was the first objective of this research. TBW was estimated in vivo in 10 native bovine calves using the conventional method (extrapolation technique) and also by the suggested modified method (equilibration technique). The averages of TBW in native bovine calves were 136.5 ± 16 and 133.1 ± 16 L by convention and modified technique, respectively, without significant differences between the two techniques. The accuracy of the modified technique was 97.5% as compared with the convention method, and at the same time, the new method is an easy, simple, accurate, and quick technique and more reliable. Estimation of heat adaptability of animals to heat stress conditions was the second objective of this research. Animals when exposed to high ambient temperature the TBW increases and consequently TBS (live body weight-TBW) decreases with different percentages according to the animal response to stressful conditions. TBW or TBS values were estimated before and after heat stress exposure and the percentage change in TBW or TBS in the animal due to heat stress may be used for evaluating the animal’s adaptability to heat stress. The percentage increase in TBW or the percentage decrease in TBS due to heat stress conditions may be used as an index for heat tolerance coefficient (HTC). The most heat tolerance animals are those with the highest HTC values.