[Estimation of body composition based on total body water determination using phenazone for assessment of body fat gain in cattle. 2. Relationship between body fat content and back fat thickness].

Back fat thickness was measured at six points in 251 beef heifers aged 3 to 17 months, in 27 beef bulls aged 15 months and in 200 Holstein dairy cows of different age. This was paralleled by estimation of body fat content based on total body water analysis. All groups of animals showed the same pattern of back fat thickness for the measuring points investigated, which lead to the result of one optimum measuring point for determination of back fat thickness. The correlation coefficients between back fat thickness and body fat content were estimated to be between 0.80 and 0.87 for all groups investigated. Change in back fat thickness by 1 mm corresponded to gain or loss of around 5 kg body fat in all animal groups. Therefore it is possible to make concrete assessments of body fat content on the basis of back fat thickness.