Effect of cultivar and formaldehyde treatment of barley grain on rumen fermentation characteristics using in vitro gas production

Abstract

The aim of this study was to determine the effects of cultivar and formaldehyde treatment of barley grains on rumen fermentation characteristics using the in vitro gas production technique. Amount of gas produced (mL/g organic matter (OM)) during fermentation was determined after 0, 3, 6, 12, 24, 48, 72 and 96 h of incubation in buffered rumen fluid. The gas production kinetics were described using the equation: y = A {1 – exp [- b (t-T) – c (√t - √T)]} where b and c are the initial gas production rate constant (h-1) and later gas production rate constant (h-1/2), respectively. Cultivar and formaldehyde treatment had significant effects on gas production kinetics. Total gas production (A) ranged from 389.9 to 410.8 (mL/g OM) with the cultivar, Esterel, producing the largest volume of gas of the cultivars. Due to low gas production rates at 3, 6 and 12 h of incubation the cultivars, Viva and Cecilla, took the longest to produce 50% of their total volume of gas. Formaldehyde treatment reduced the rate (μ) of gas production at 3, 6 and 12 h of incubation, and the total volume of gas (A), but increased the time (h) to produce 50% of A and reduced the time (h) to produce 95% of A. The reduction in gas production ranged from 33.3 to 51 mL/g OM with 6 h incubation showing the highest decrease in gas production. It is concluded that formaldehyde treatment may provide an opportunity to manipulate the site of digestion of barley grain in the digestive tract of ruminants. Through the selection of suitable cultivars and through formaldehyde treatment the nutritional and health problems associated with the fermentation of barley grain in the rumen could be reduced.

Keywords: Barley cultivars; formaldehyde treatment; gas production kinetics

South African Journal of Animal Sciences Vol. 35 (3) 2005: pp.206-212