The feeding value of grain screenings for ruminants: Chemical composition and nutrient utilization

Abstract

The objectives of this study were to determine the chemical and nutrient utilization characteristics of grain screening pellets (GSP) for ruminants. One ruminally fistulated cow was used to determine ruminal nutrient degradability characteristics of GSP relative to barley grain. Twenty-one growing lambs were used to determine voluntary intake and total tract nutrient digestibility coefficients for GSP relative to regular and thin barley. Seven diets were formulated with different levels of GSP, and thin or regular barley at ratios of 100:0; 75:25; 50:50; 25:75. On a dry matter (DM) basis, GSP contained 337 ± 17.4 g kg−1 neutral detergent fiber (NDF), 209 ± 21.1 g kg−1 acid detergent fiber (ADF), 151 ± 11.1 g kg−1 crude protein (CP), and 262 ± 61.5 g kg−1 starch. Ruminal degradability of DM and NDF of GSP was lower (P < 0.05) while that for CP was higher (P < 0.05) than barley grain. Effective ruminal degradability of starch for GSP and barley exceeded 900 g kg−1. Results of the sheep trial showed that as the level of GSP increased, voluntary intake increased (P < 0.05) and total tract digestibility coefficients of DM, NDF, and gross energy (GE) decreased (P < 0.05). The digestibility coefficients of DM, NDF, and GE for GSP were 666 g kg−1, 294 g kg−1, and 698 J kJ−1, respectively. The digestible energy (DE) content of GSP (13.8 MJ kg−1) was similar to that of thin barley and 11% lower (P < 0.5) than that of regular barley. It was concluded that while GSP exhibited reduced ruminal and total tract nutrient utilization relative to regular barley, this feed product is a good source of energy and protein for growing ruminants. Key words: Grain screening pellets, barley, thin barley, nutrient utilization