Published online by Cambridge University Press: 02 September 2010
The errors of the slaughter and tritiated water techniques of estimating energy retention were compared in a group of grazing sheep deprived of feed and water for 48 hr. It was calculated that the mean energy retention of the experimental animals would have had a standard error of 3·64 Mcal if estimated by the slaughter technique, and 1·56 Mcal if estimated by the tritiated water technique. It was concluded that in other experimental groups the precision of the relationship between energy content and live weight is likely to be the most important determinant of the relative precision of the two methods. In neither method would worthwhile gains in precision result from knowledge of the weight of the contents of the alimentary tract.