Comparison of 7- and 10-Day Collection Periods in Digestion and Metabolism Trials with Beef Heifers

Abstract

Sixteen individual digestion and metabolism trials, using 4 heifers and 4 rations, were conducted to compare 7- and 10-day collection periods. The 4 rations were 2 protein and 2 energy levels arranged in a factorial design. The low energy rations were 89% roughage and the high energy rations were 39%. Harnesses with feces and urine separators were used to make total collections. With the exception of crude protein and crude fiber digestibility there was less variation associated with the coefficients calculated from the 10-day collection period. There was no significant difference in the digestion coefficients, metabolizable energy or N retention determined from the 2 methods regardless of the type of ration. In this study high correlations based on the averages of each ration, indicate a 7-day collection period is sufficiently accurate for predicting the average of the same heifers on a 10-day collection period when 4 heifers are used in the average.