Effect of pregnancy on intake, digestibility and digesta kinetics in heifers fed urea treated rice straws

Abstract

Five rumen fistulated heifers weighing 298±4 kg, fed ad libitum urea treated rice straw were used during trimesters 1, 2, and 3 of pregnancy. Voluntary dry matter intake (VDMI), dry matter (DM) and neutral detergent fibre (NDF) digestibility, rumen pool sizes and passage rates were measured. Indigestible NDF was measured by long incubation in situ and used to derive digesta kinetics. The VDMI, digestion and passage rates for DM and NDF fractions, increased (P<0.05) between the 1stl and 3rd trimester. In conclusion, pregnant heifers fed high NDF based diets, maintains high forage intake by increasing digestion and passage rates.