The energy value of whole oats grain in adult wether sheep

Abstract

Samples of Cooba and Coolabah oats were chosen on chemical analysis to represent relatively high and low quality grain. Each was evaluated by measuring energy, nitrogen and carbon balances in 4 adult sheep at several levels of feeding and during starvation. The Cooba contained, on a dry matter (DM) basis, 14% crude protein (CP), 23% cell wall constituents (CWC) and 19.1 MJ/kg gross energy (GE); the Coolabah had 10% CP, 31% CWC and 19.6 MJ/kg. With ad libitum feeding, respective DM intakes were 1.4 and 1.8 kg/day (3.3 and 4.4 times maintenance) giving daily retentions of 6.6 and 8.2 MJ and 6.2 and 8.0 g nitrogen. The availabilities of the gross energy of the Cooba at maintenance were 85% digestible energy (DE), 71% metabolisable energy (ME) (13.6 MJ/kg DM), 59% net energy (NE); when assessed as a production supplement, the values were 79,74 and 38% respectively. The results for Coolabah were 76% DE, 68% ME (1 3.3 MJ/ kg), 53% NE (maintenance); 64% DE, 6 1% ME, 36% NE (production supplement). It is apparent from the present and previously published results that the GE and ME/DE values of oats are higher than commonly supposed. Furthermore, although protein and fibre content indicate the relative digestibilities of feeds, they are not a good guide to relative NE values nor to attainable production in terms of either energy or protein.