Chemical composition and in situ degradability of two varieties of sugarcane at different growth stages in subtropical Japan

Sugarcane is an important crop and also a potential feed resource in the Southwestern Islands of Japan. We investigated chemical composition and in situ degradability of two Japanese sugarcane varieties, a common variety, NiF 8 and a new variety developed for cattle feed, KRFo 93-1. We also evaluated these sugarcanes as alternatives to sugarcane top and imported oaten hay, i.e. commonly used roughages in the Southwestern Islands. The crude protein (CP) contents of both sugarcane varieties were usually lower than those of sugarcane top and oaten hay, showing a decrease with advancing maturity after ratooning. On the other hand, the non-fiber carbohydrate contents of both varieties and the effective degradability of dry matter in NiF 8 increased with advancing maturity, possibly due to sucrose accumulation. The effective degradability of neutral detergent fiber for KRFo 93-1 decreased with advancing maturity, being lower than that for sugarcane top and close to that of oaten hay. Overall, highest nutritional benefits would be obtained at a later stage harvest for NiF 8 and at an earlier stage harvest for KRFo 93-1. CP and/or energy supplements are needed when either of the sugarcane varieties is used as an alternative to sugarcane top or imported oaten hay.