Composition of by-products of the essential-oil industry and their potential as feeds for ruminants

Eight plant-residues from the essential-oil industry were assayed for chemical composition. Digestibility of the plant residues was determined by rumen fermentation in vitro and in vivo. Dry-matter digestibility of plant residues from black pepper, vanilla bean, ginger root, cocoa bean and celery seed ranged from 43–65%. Only 15–30% of the residues from nutmeg hulls and cinnamon bark were degraded. These data indicate that anaerobic microbes are capable of degrading significant quantities of the plant residues without further processing of these materials. Long-term feeding studies need to be conducted to determine if ruminants will consume these plant materials, and to investigate the effect of these plant residues on rumen microbial- and host cellular-metabolism.