The effect of concentrate supplementation on voluntary intake, digestibility and composition of rumen fluid of goats fed on rye (Secale cereale L.) silage

Voluntary intake, digestibility and composition of rumen fluid in goats were measured in order to determine the effect of concentrate supplementation when fed with rye silage. Twelve goats were grouped into tetrads by experimental diets as follows: group I (control); rye silage alone, group II; rye silage with concentrate at 0.1%, group III; rye silage with concentrate at 0.5%, group IV; rye silage with concentrate at 1% of body weight. Daily body weight gain (DG) of the groups supplemented with concentrate was higher than that of group fed with rye silage alone and it was significantly high when the animals were supplemented with concentrate at 0.1 and 0.5% of body weight (p0.05). Digestibility of dry matter (DMD) increased in proportion to increasing the amount of concentrate and there were significant differences (p0.01) between control and groups supplemented with concentrate at 0.5 and 1% of body weight. Those of NFE, OM and energy were similar to the result of DMD. For total VDMI and DDM, TDN and DCP intake the differences were significant (p0.05) between groups. Voluntary dry matter intake of rye silage alone did not change in control, group II and III, but it exhibited great decrease in group IV (p0.05). Although the figures decreased gradually as increasing the supplementary level, there were no significant differences in pH values and total VFA concentrations except for group IV (p0.05). There were no significant differences between groups for ammonia-N concentrations at 2 hr after feeding but its concentration of control was the highest (P0.05) of all groups at 6 hr after feeding. It is concluded that supplementation of concentrate in goats fed with rye silage had progressively influenced on digestibility of DM, NFE and OM, voluntary intake and daily gain, but supplementation above 0.5% of body weight was not effective owing to the reduction of silage intake and ruminal pH value