Spent tea leaf as a ruminant feed

Spent tea leaf (STL), a residue from the manufacture of instant tea, has 30% crude protein and contains significant quantities of essential amino acids. Because of its high polyphenol content it may not be suitable for pigs and poultry, but in view of the more tolerant nature of microflora to tannins it could be a potential source of protein for ruminants.Three trials were conducted with cattle or sheep to evaluate STL as a ruminant feed. In Trial I, three concentrate rations prepared with 0, 10 or 20% STL were found to be readily acceptable by bull calves 6–8 months of age, without any harmful effects upon their health. In Trial II, four concentrate rations having 0, 10, 14 or 18% STL were found to be equally digestible by sheep.In Trial III, groups of 7 male Jersey calves, 5 months old, were given 0, 10 or 18% STL in concentrate rations, and rate of growth and concentrate conversion efficiency were investigated. There was no significant difference between the groups in live-weight gain, which suggests that up to 18% STL may be used in concentrate rations without apparent health problems. The average daily gains for the 3 rations were 288, 274 and 271 g, respectively. On the basis of cost/kg live-weight gain, a ration containing 18% STL would be 25% cheaper than a standard concentrate ration.