Effects of cutting height and age at harvest on chemical composition of elephant grass (pennisetumpurpureum “schumach.”) grown in the south-eastern Nigeria

The nutritive value of grass for livestock is influenced by the dry matter consumed, its chemical composition, and digestibility. The study, conducted at the Teaching and Research Farm of Michael Okpara University of Agriculture, Umudike, aimed to investigate the effect of cutting height and harvest age on the organic chemical composition of Elephant grass (Pennisetum purpureum Schumach). Using a 4 x 3 factorial layout in a Completely Randomized Block Design with three replicates, the study involved treatments of four cutting heights (0, 10, 20, and 30 cm) and three harvest ages (30, 60, and 90 days), totaling twelve treatments. Field underwent a standard preparation, divided into blocks (2.5m x 34.3m) and plots (2.5m x 2m). Basal NPK 15:15:15 applied at 100 – 150 kg/ha by broadcasting. Crown splits were planted at 50 x 40 cm spacing (5 rows/plot, 5 stands/row). Harvested forage was weighed, dried and the ground subsamples sent for chemical composition parameters analyses using a standard scientific method. Data collected were analyzed using Genstat statistical package and mean separation was carried out using Fishers’ least significant difference. Results showed that with a 90-day harvest, grass dry matter, carbohydrate, ether extract, and essential minerals contents, significantly increased (P<0.05), while phytate, cyanogenic glycoside, and flavonoid contents significantly decreased (P<0.05). Additionally, a 30-day harvest yielded higher crude44 protein and ash contents, with lower crude fiber, alkaloid, and saponin contents compared to 60 or 90 days. Therefore, cutting height and harvest age can significantly enhance the nutritive value of Elephant grass for livestock.