Supplementation of Beef Cows Grazing Natural Pasture with Crude Glycerin and Whole Rice Bran

Abstract

To study the effects of supplementation with crude glycerin (GC) and whole rice bran (AA) on ruminal dynamics, kinetics of dry matter (DM) degradation, forage intake and plasma variables associated with energy balance in beef cows grazing natural pasture, four rumen fistulated cows were allocated to a latin square 4 × 4 with an additional period. The treatments were: supplementation with GC (550 mL/cow/day), supplementation with AA (1 kg DM/cow/day), supplementation with GC + AA (550 mL/cow/day + 1 kg DM/cow/day) and without supplementation (CON). The daily forage allowance for all treatments was 10 % of live weight. GC associated or not to AA decreased ruminal pH on the first six hours pos-supplementation, but did not affect any parameters of degradability of forage DM. GC supplementation decreased forage intake but did not affect total DM intake and metabolizable energy (ME) compared with CON. GC + AA and AA supplementation did not differ on intake of forage and total DM, however the ME intake was higher for GC + AA compared to the rest. GC + AA supplementation increased plasma concentration of glucose and insulin without affecting B-hydroxibutirate. Among the supplements tested, GC + AA mixture (higher level of supplementation) achieved the best biological results.