Interspecies differences and variability with time of protein precipitation activity of extractable tannins, crude protein, ash, and dry matter content of leaves from 13 species of Nepalese fodder trees

Dry matter ash, crude protein, and protein precipitation activity (PPA) of 13 Nepalese tree fodder species were monitored in dried samples prepared monthly between November 1990 and May 1991, and additionally in November 1991, covering the season when they are particularly important as fodder. Monthly levels of dry matter ash, and crude protein were fairly stable except when there was new leaf growth, although year to year differences in dry matter were found in Brassaiopsis hainla (Bh), Dendrocalamus strictus (Ds), Ficus roxburghii (Fr), and Quercus semecarpifolia (Qs). Tannin PPA fluctuated considerably in Anocarpus lakoocha (Al), Ficus glaberrima (Fg), F. nerrifolia (Fn), Fr, F. semicordata (Fs), Litsea polyantha (Lp), and Prunus cerasoides (Pc), and to a lesser extent in Bh, Castanopsis indica (Ci), C. tribuloides (Ct), Quercus lamellosa (Ql), and Qs. Similar fluctuations in PPA were observed in fresh leaf samples taken weekly. Ds did not have any detectable PPA. Trends in PPA fluctuation were generally similar for trees located at similar altitudes. Fr, Pc, Al, Fn, Ql, and Ci had falling PPAs before shedding leaves. Some of the fluctuations in Fr, Fs, Fg, Pc, and Lp were apparently due to changes in the extractability and quantity of condensed tannins. These fluctuations in PPA may affect the nutritive value of the fodders