Seasonality of polyphenolic compounds in nine important tree fodders in the eastern hills of Nepal

Polyphenolic compounds in 9 important tree fodders in the eastern hills of Nepal were measured in leaves at 2 stages (young and mature) and in twigs during the spring, summer, monsoon and winter seasons of 1995. Among the species studied, kutmiro ( Litsea monopetala ), koiralo ( Bauhinia variegata ), syalfusro ( Grewia tiliaefolia [G. tiliifolia] ) and gogun ( Saurauia napaulensis ) contained high lignin, and kutmiro and koiralo contained high tannin. The other species studied were tanki ( Bauhinia purpurea ), badahar ( Artocarpus lakoocha ), khari ( Celtis australis ), ghotli ( Grewia oppositifolia ) and chuletro ( Brassaiopsis hainla ). No statistically significant trend in lignin content between seasons was observed in any species, although the lignin level was slightly higher over all species during the pre-monsoon and monsoon seasons compared with the spring and winter seasons. The tannin content was higher during the spring in most of the species studied, but the level of tannin was lower than that which adversely affects animals. There was also a positive relationship (r²=0.72 at p <0.01) between the levels of lignin and tannin.