Effect of Organic Manure and Harvesting Age on Morphological Parameters, Yield and Physical Silage Quality of Brachiaria ruziziensis

Abstract

Forage productivity and quality in ruminant nutrition depend on factors such as organic manure application and harvesting age, necessitating evaluation of their combined effects on Brachiaria ruziziensis yield and morphology.The aim of this study was to evaluate the impact of different organic manure (poultry manure, cattle manure and pig manure) and harvesting age (8, 12 and 16 weeks after planting) on the morphological parameters, yield and physical silage quality of Brachiaria ruziziensis. The experiment was conducted in Pasture unit of the College of Animal Science Teaching and Research farm, Joseph Sarwuan Tarka University Makurdi, Benue State, Nigeria. The research was laid out in a randomized complete block design (RCBD) in a 4 x 3 factorial arrangement, 4 different manure application (no manure application, poultry manure, cattle manure and pig manure) and 3 harvesting age (8, 12 and 16 weeks after planting). Data on morphological parameters (plant height, leaf length, leaf width and leaf to stem ration) and dry matter yield of Brachiaria ruziziensis were subjected to analysis of variance using SPSS version 20 at 95% probability level. Previous studies largely focused on the effect of manure on forage growth and yield but limited attention has been given to how nutrient sources affect the physical characteristics and preservation quality of silage. This study therefore expands existing knowledge by linking organic nutrient management not only to forage productivity but also to post-harvest feed quality. Forages harvested at 12 and 16WAP was ensiled for 21 days after which it was opened and evaluated, the physical examinations employ a subjective analysis and checked for odor, structure, color, pH and moisture content of the silage. The silage quality class according to the physical properties of the silage was determined by the DLG (Deutsche Landwirtschafts-Gesellschaft) score. All morphological parameters and DMY were not affected (P>0.05) by manure type while plant height and DMY increased (P<0.05) as harvesting age progressed. However, the interaction effect of manure type and harvesting age showed that forages established with poultry and cattle manure and harvested at 12 WAP gave a higher (P<0.05) DMY compared to those established with pig manure and harvested at the same period. Manure type adopted in this study did not interfere with silage production process as they all gave pasture suitable substrate for successful fermentation resulting in good silage.  Silage harvested at 16 WAP was rated very good silage, while that from 12 WAP was rated good.