Dioscorea alata

Winged yam, water yam, greater yam

The most important of the cultivated varieties of yam. The white, brown or brownish red root tubers are very large, sometimes over 2 m in length, penetrating deep into the soil. The water content of the tubers is high. The stem is a climbing type with leaves 0-20 cm long. Growing yam for animal feed is seldom economic, but yam can be used where surpluses are available. The peels are a valuable cattle feed. The tubers of all other types are more palatable cooked than raw, because cooking destroys the poisonous bitter alkaloid dioscorene.

					As % of dry matter
				DM	CP	CF	Ash	EE	NFE	Ca	P	Ref
Fresh aerial part,
Malaysia				24.1	12.0	25.3	7.9	2.3	52.5	0.95	0.16	292
Fresh tubers,
Nigeria				34.2	8.1	2.6	5.2	0.8	83.3	0.12	0.18	374
Fresh tubers,
peeled, Nigeria				26.2	7.3	2.3	5.2	0.6	84.6			"
Fresh peelings,
Nigeria				25.9	11.7	6.6	9.5	1.0	71.2			"
					Nylon bag degradability
						a	b	c		12hr	48hr	Ref
						(%)	(%)	(/hour)		(%)	(%)
Yam peel, Ghana					DM	45.6	32.1	0.0603			75.8	627
	[P (rumen degradability at time t) = a+b*(1-exp(-c*t))]