THE EFFECT OF REPLACEMENT OF WHEAT BRAN BY GRADED-LEVELS OF MOLASSES ON DIGESTION, DEGRADATION AND DIGESTION KINETICS OF FIBER AND RUMEN DIGESTA POOL SIZE IN CROSSBRED (BOS-TAURUS X BOS-INDICUS) STEERS FED NATIVE GRASS HAY
H. Khalili et Po. Osuji, THE EFFECT OF REPLACEMENT OF WHEAT BRAN BY GRADED-LEVELS OF MOLASSES ON DIGESTION, DEGRADATION AND DIGESTION KINETICS OF FIBER AND RUMEN DIGESTA POOL SIZE IN CROSSBRED (BOS-TAURUS X BOS-INDICUS) STEERS FED NATIVE GRASS HAY, Animal feed science and technology, 47(3-4), 1994, pp. 213-223
This 4 x 4 Latin square experiment evaluated the effect of replacement
of wheat bran by graded levels of sugar cane molasses on digestibilit
y, degradation of fibre, digestion kinetics of fibre and rumen pool si
zes. Four ruminally fistulated crossbred (Bos taurus X Bos indicus) st
eers were given a basal diet of grass hay ad libitum and 4.0 kg dry ma
tter (DM) of wheat bran day-1 (Diet MO). The other three diets consist
ed of replacement of wheat bran with 1.0 (Diet ML), 2.0 (Diet MM) or 3
.0 (Diet MH) kg DM of molasses. Urea was used to make the three diets
(ML, MM and MH) isonitrogenous with the basal diet (MO). Intake and di
gestibility of neutral detergent fibre (NDF) decreased from 4.65 to 3.
31 and 0.65 to 0.55 (linear effect, P<0.01) with increasing levels of
molasses. Similarly, NDF digestion expressed as a proportion of potent
ially digestible NDF decreased linearly (P<0.01) when the level of mol
asses increased. The disappearance of hay DM from nylon bags decreased
(significant linear effect after 48 h incubation period and onwards,
P<0.05) with increasing wheat bran substitution by molasses. The disap
pearance of NDF of hay from nylon bags decreased significantly only at
48 h (linear effect, P<0.01) and at 96 h (quadratic effect, P<0.05) w
hen the amount of molasses increased. Although there were differences
between diets in rumen pool sizes of DM, NDF and in digestion kinetics
of NDF, these were not, in general, explained by polynomial orthogona
l contrasts. Increasing the level of molasses caused a clear linear ef
fect (P<0.01) only for mte of digestion (k(d)) of NDF and true rate of
digestion (k(dt)) of NDF. There was also a quadratic effect (P<0.01)
for rate of passage (k(p)) of indigestible NDF, showing that diets ML
and MM had greater rate of passage compared with the other two diets w
hen the level of molasses was increased.