Body Composition of Cattle. I. Estimation of Body Fat From Measurement in Vivo of Body Water by Use of Antipyrine

Abstract

Body water measurements on 30 head of beef cattle were made by intraven. admn. of antipyrine. Antipyrine is distributed uniformly in the various tissues proportional to the water content. Body fat values were calculated from body water values on the basis that fat-free tissue in the normal adult of the mammalian spp. has been shown to be relatively constant at 73.2% water. The rate of transformation of the drug in cattle is on the avg. 25%/hr. Approx. 2.5 hrs. were required for essentially complete distr. of the drug in the body water of cattle. Body water and body fat values detd. by the antipyrine method agree well with the those obtained by specific gravity technic. In the 30 head of cattle the water content detd. by antipyrine method ranged from 43.9 to 63% and body fat ranged from 40.1 to 13.9%. In a group of Hereford cattle on a high plane of nutrition, a sex difference in fat content was demonstrated, the heifers with an avg. of 32.5% fat and the steers with an avg. of 27.5% fat within the same wt. range and at comparable ages.