Some forest, timber and paper mill residues in animal feeding

Abstract

Young tress, natural residues (foliage, twigs, shoots, blades, bark) and subproducts from the timber industries and paper mills have been sources of feed and feedstuffs to animals, specially when shortages of the comun one arise, The nutrive value of the first varies with species, age and growing conditions and utilization; moreover, in the second ones the type of tecnology applied has to be taken into account. Generally is known that depends on the proportion of natural ligno-cellulosics and antinutitive substances (tannins, polifenols, etc.) and of chemicals added during the different industrial processes. Nevertheless more data on chemical composition and feeding trials are needed in order to ascertain its nutritive value (ingestibility, digestibility and metabolic eficiency) and place in the ration, before and after physical, chemical or biological treatments. Moreover options as composting, incineration or processing to obtain silvochemicals has to be analized not only from the economical point of view but having in mind their effects on the sustainability of the ecosystems.