Effect of kinds of hay on population densities of rumen anaerobic fungi

Abstract

To clarify the relationship between population densities of rumen anaerobic fungi and the chemical composition of grass and legume hays, rumen fermentation and retention time of particles in the rumen, male Corriedale sheep (3) were given either oats hay. timothy hay or lucerne hay chopped to 2 cm @ 2.5 % of live weight in the Latin square design. The passage rate of particulate and liquid fractions, volatile fatty acids and population densities of rumen fungi were characterised. Population densities of rumen fungi were determined by roll-tube method and agar-strip method. Population densities of ruminal fungi did not correlate with the chemical composition of oals, timothy and lucerne hays nor with rumen fermentation in the present study. Results of fractional outflow ratc or mean retention time of digesta particles suggested that a slower outflow rate or a longer mean retention time of particles offers a higher possibility of fungal growth on digesta particles greater than 0.30 mm in the rumen.