Ruminai degradability of soybean oil meal and coast-cross hay, with canulated steers fed different ratios of roughageconcentrate in their diets

Abstract

This work evaluated ruminal degradabilities of soybean oil meal dry matter (DM) and protein (CP), and of coast-cross hay DM and neutral detergent fiber (NFD), through nylon bag technique in situ. For treatments were used different proportions of roughage in D M. rations: A = 40%; B = 60%; C = 80% and D = 100% hay. Sixteen steers with rumen canulas were used in a randomized block design with two replicates for each treatment inside blocks, all diets balanced for nitrogen. DM degradability of soybean oil meal with 24 h of incubation time increased linearly (p < 0.05), with higher levels of roughage from 77.9% to 88.1%. CP degradability of soybean oil meal presented no differences among treatments, with values between 81.7% and 90.4% at 24 h of incubation time. Hay DM and NDF degradabilities showed smaller values (p < 0.01) in the lower roughage level (40%). Total protozoa concentration in rumen fluid showed quadratic regression (p < 0.01), with smallest concentration for the lower roughage level (40%).