Evaluation ofcenchrus ciliaris: 1. Effects of nitrogen level and cutting frequency on digestibility and voluntary intake

Cenchrus ciliaris (cv. Molopo) was cut at 3, 5 and 7 week intervals and fertilized with 50, 160 and 270 kg N/ha respectively. The treatments provided hay of nine different qualities with a range of ash (8,5 to 10,6%), N (0,9 to 2,5%) crude fibre (38,5 to 45,4%), in vitro digestibility (53,8 to 70,5%) and voluntary intake (57,1 to 70,3 g/kg W0,75). Unfertilized C. ciliaris and C. ciliaris fertilized with 50 and 100 kg N/ha and cut at eight weeks provided three qualities of hay with a range of ash (8,5 to 10,1%), N (0,6 to 0,9%) and fibre (42,9 to 44,7%). The hay of the 0, 50 and 100 kg N/ha treatments varied in in vitro digestibility (61,2, 63,5 and 59,0%), in vivo digestibility (49,3, 57,9 and 59,3%), voluntary intake (50,1, 67,5 and 65,1 g/kg W0,75) and mean daily livemass gain/ sheep (—4,5, 57,3 and 52,8 g), respectively. It is concluded that voluntary intake provides one of the best measures for determining the nutritive value of C. ciliaris.