Ensilage potential and nutritional value of Columbus grass (Sorghum almum Parodi) at different phenology and storage duration in the derived savanna zone of Nigeria

Abstract

Insufficient forage supply from natural rangelands during the dry season hampers ruminants' performance in the derived savanna zone of Nigeria. Therefore, to provide alternative feed resources, we evaluated silage potential of Columbus grass (Sorghum almum Parodi) at boot, dough and maturity stages for 4-, 8-, 12- and 16-week ensiling durations, in a 3 × 4 factorial experiment. The dry matter yield (DMY) was determined at each harvest stage, and the forages were subsequently ensiled. The results revealed that the DMY of S. almum at maturity was 8.98% and 18.67% higher than at dough and boot stages, respectively (p < 0.05). The silages were ranked “good silage” based on physical characteristics. Silage pH decreased with advancing ensiling duration from 4 to 16 weeks in boot (5.25–4.63), dough (5.63–4.11) and maturity (5.42–4.91), with a corresponding increase in lactic and volatile fatty acids. Crude protein (CP) was higher in forages ensiled at maturity and increased with ensiling duration after initial decline from 4 to 8 weeks. Neutral detergent fiber (NDF) and hemicellulose increased quadratically from boot to dough and subsequently declined at maturity. Growth stage, ensiling duration and their interactions influenced the macrominerals' content (p < 0.05). Silages' dry matter intake (DMI) declined from boot to dough stage across the ensiling durations, and except for 8 weeks, the DMI increased at maturity by 6.71%, 5.54% and 7.19% in 4, 12 and 16 weeks, respectively. Therefore, owing to the lower NDF and high DMY, CP and DMI of S. almum ensiled at maturity for 16 weeks, it could guarantee a quantitative and qualitative forage supply to maintain optimum animal performance throughout the dry season.