Effects of bicarbonate on rumen degradability of concentrate and grass hay in Angora goats

Abstract

Three rumen-fistulated Angora goats were used to assess the effects of NaHCO 3 on rumen degradability and fermentation of concentrates and grass hay in Angora goats. Animals were fed a basal diet (1) (30% concentrates and 70% grass hay); basal diet supplemented with 1.34% (2) or 3.35% (3) NaHCO 3 using a 3 × 3 Latin square design with 15-d periods. The 24-h dry matter loss (DML), potential degradability ( a + b) and rate of degradation ( k) values of concentrates and grass hay were highest for 3.35% NaHCO 3 followed by 1.34% and 0% NaHCO 3 ( P<0.01). Addition of 3.35% NaHCO 3 had the highest effect on the ( a + b) values of concentrate and grass hay. Differences in the ( a + b) and k values between diets 1,2 and diets 1,3 were significant ( P<0.01). The asymptotic values ( a + b) and k values of grass hay and concentrate for diet 2 were higher than for diet 3 ( P<0.02). Ruminal total VFA, NH 3-N concentration and pH of rumen fluid were increased with increasing levels of NaHCO 3.The two graded levels of NaHCO 3 resulted in higher ( P<0.01) rumen NH 3-N and total VFA concentration 2 h after feeding compared with 0 level. Also higher ( P<0.01) ruminal pH values were observed with the 1.34 to 3.35% levels. Addition of NaHCO 3 at 1.34 to 3.35% may be beneficial, in practice, for Angora goat production.