Feeding value to goats of whole-crop oat ensiled with green tea waste

A study was made with goats to the feeding value of whole-crop oat silage with and without the addition of green tea waste (GTW). The GTW was from a local beverage company, dry matter (DM) content of 222.7 g/kg and the following composition (g/kg DM): water soluble carbohydrates, 8.8; crude protein (CP), 276.3; and condensed tannins (CT), 91.0. GTW was added to whole-crop oat silage at a rate of 0, 50 and 200 g/kg fresh matter, and then ensiled for about 50 days. After fermentation, all silages showed low pH (<4.13), and lactic acid concentrations were significantly higher (P<0.05) in the GTW treatments than in the control. Lower proportions of NH3-N/total N were observed in the GTW-treated silages. In addition, GTW treatments increased CP and CT contents of the silages. tter intake of silages by goats was not significantly different among treatments. GTW treatments did not significantly affect in DM digestibility, but CP digestibility was significantly increased (P<0.05). GTW treatments increased N intake, but did not affect N excretion in urine and feces, resulting in an improved N retention. Ruminal NH3-N concentration was significantly increased (P<0.05), while volatile fatty acids concentrations were lower in GTW-treated silages, compared with the control. It is concluded that proteins in GTW seem to be stable during ensiling, but digestible post-ruminally. Based on high CP content, N digestibility and N retention of GTW-treated silage in goats, GTW has a potential as a protein supplement to livestock.