Fermentation and nutritive value of silage and hay made from the aerial part of cassava (Manihot esculenta Crantz)

Abstract

Cassava (Manihot esculenta Crantz), although native to Brazil, is still underutilized, especially when it comes to using its aerial part. In order to study the potential of the cassava plant for use as animal feed, the present work evaluated the characteristics of the aerial part of cassava when submitted to the processes of ensiling and haymaking. Treatments consisted of: aerial part of the plant ensiled without wilting (PAS); aerial part ensiled after wilting (PAE), and aerial part made into hay (PAF). Chemical analyses were run in order to evaluate the traits that determine the nutritional value of silage and hay. Wilting increased dry matter concentration from 25% to 27.7%, without changing the concentration of soluble carbohydrates (33.3 and 35.5% in the PAS and PAE, respectively), as well as buffer capacity (204 mmol kg-1 DM in PAS and 195 mmol kg-1 DM in PAE). Neither pH (3.57 in fresh silage and 3.60 in PAE) nor the ADIN concentration (11.32% of total nitrogen in PAS and 9.99% of total nitrogen in PAE) differed between the silages, but ADIN concentration was higher in hay (15.39%). Wilting caused an increase in the concentration of ammonia (from 6.5% of total nitrogen in PAS to 13.0 of total nitrogen in PAE). The levels of volatile fatty acids did not change with wilting. The ensiling process reduced the concentrations of free hydrocyanide (HCN), without, however, affecting cyanohydrin.