The objectives of this study was to determine the optimum level of water hyacinth (WH) in the basal diets of Para grass (Brachiaria mutica) on nutrient intakes and digestibility, nitrogen retention and rumen environment of growing goats. Four Bach Thao female goats were allocated in a Latin-square design with four treatments including water hyacinth levels replacing Para grass at levels
of 25, 50, 75 and 100% in the diets based on DM basis corresponding to the WH25, WH50, WH75 and WH100 treatments. Soybean cake meal and urea were supplemented in the diets to adjust the dietary CP intake of 6 gCP/kgBW per day. The results indicated that the daily DM intakes were of 494, 464, 432, 408 g for the WH25, WH50, WH75 and WH100 treatment, respectively (P>0.05). While the other nutrient intakes were significantly different (Pincreasing the WH in the diets. Rumen N-NH3 and VFAs concentration proportionally decreased when increasing water hyacinth in the diets. There was no significant difference of the nutrient digestibility and nitrogen retention (P>0.05). The conclusion was that fresh water hyacinth could replace Para grass in diets of growing Bach Thao goat at the level of 75% without any negative effects.

Keywords water plants, small ruminants, feed utilization, digestion, rumen parame