THE NUTRITIVE VALUE OF HAY FROM FOUR GRASS SPECIES CUT AT THREE STAGES OF GROWTH AT IBADAN

Abstract

Four grass species namely: Cynodon nlemfuensis var robustus (M); Pennisetum purpureum Schum (N); Cynodon nlemfuensis var nlemfuensis (P); and Panicum maximum Jacq. (Q), each between the 4th and 5th, 6th and 7th, and 8th and 9th week of regrowth, was cut in the fourth and fifth years of grazing for hay (i. e. in 1972 and 1973). Digestion trials with West African dwarf sheep showed that there were significant differences in the extent to which the dry matter of the different grass species was digested (P 0.001) and among the stages of growth (P 0.01). The differences between animals within and between treatments and the interactions between treatments and periods of cutting were statistically not significant. The differences among treatment means indicated that treatment Q (68.5 ± 2.73%) was digested better than treatment M (54.9 ± 7.18%, P 0.001), and treatments N and P (60.3 ± 5.37% and 58.7 ± 5.30% P 0.01) respectively. The digestibility of crude protein was generally low in each of the grass specie studied. This is probably a reflection of the low crude protein content of the grass hays which was below 9 percent of dry matter. It ranged from approximately 27.3 percent in treatment N for the 6th week regrowth hay to 51.9 percent in treatment Q for the hay harvested in the 8th week of regrowth. The differences among treatments, stage of maturity, and the interactions between treatments and stage of cutting were not statistically significant. Significant differences between treatments were observed in the digestion of the energy content of the feeds (P 0.001). Treatments N and Q were better digested than M and P (P 0.05). Expressed on metabolic size basis, the intakes of dry matter, crude protein, and energy showed significant differences between treatments and between ages at harvest. The intakes of dry matter in treatments Q, M, and P were significantly higher (P 0.05) than treatment N while there was more dry matter taken from the 4th and 8th week hays than from the hays made from the species harvested in the 6th week of regrowth (P 0.01). More crude protein was consumed per kg0.75 in treatments M, P and Q than in treatment N (P 0.01), and in treatment M than Q (P 0.05). There were higher protein intakes from hays made in the 4th and 8th than those made in 6th week of regrowth (P 0.05). Treatment Q supplied more energy per kgl. 75 than treatments M, P and N (P 0.05), while more energy was consumed per kilogramme of metabolic size in treatment P than in treatment N (P 0.05).
 Nutritive Value of Hay. The intake of digestible crude protein was relatively low and this probably accounted for the losses in the liveweight of the experimental animals. The results of the experiment are suggestive of the need for supplementary protein feed during the dry season if animals are to make any liveweight gains.