Effect of manure and harvesting age on physical and chemical properties of Pennisetum hybrid silage

Abstract

This study was conducted to investigate the combined effect of manure type and harvesting age on physical properties and chemical composition of silage produced from Pennisetum hybrid forage. The manure types were from cattle, poultry, swine, goat, while the harvesting times were 4 and 8 weeks after cutback (WAC). Colour results varied significantly (P < 0.05). Dry matter, ether extract, crude fibre, ash, crude protein (CP), neutral detergent fibre, acid detergent fibre and lignin contents of the silage varied significantly (P < 0.05). Higher CP content (91.0 g.kg-1) of the silage was obtained from the interactive effect of poultry or goat manure and 4 WAC harvesting age of Pennisetum hybrid. Higher ash content (330.0 g.kg-1) was recorded for the combined effect of goat manure and 4 WAC on the Pennisetum silage, while the least (70.0 g.kg-1) occurred in grass without manure application sampled 8 WAC. Higher Ca (7.14 g.kg-1) was recorded in silage from swine manure and 4 WAC harvesting age effect. Phosphorus content of the silage was higher (2.57 g.kg-1) with poultry manure and 8 WAC effect, while the least (1.01 g.kg-1 and 1.98 g.kg-1) were from no manure effect at both harvesting ages. Crude protein content of silage made from the Pennisetum hybrid fertilized with either poultry or goat manure and harvested at 4 WAC was the best. Physical properties of the silage were generally of acceptable/desirable grades. With or without the manure application, the minerals of the silage were generally higher than the recommendation of ruminants.