Effect of harvest stage and additives on fermentative and nutritional quality from dualpurpose sorghum (Sorghum bicolor) silage in livestock production systems

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Résumé

To address the shortage of animal feed in Burkina Faso, we looked at the potential for producing silage
from forage sorghum and the main factors affecting the fermentation process. The aim of this study was to evaluate the chemical composition, fermentation quality, and microbial dynamics of silage prepared from dual-purpose sorghum (Sorghum bicolor, variety Sariaso 16) harvested at two stages of maturity (soft dough and mature stover) under Sudanian agro-ecological conditions in Burkina Faso. Sorghum forage was ensiled with different additives (molasses, salt, molasses + salt) and compared with untreated control silages. Results revealed that sorghum harvested at the soft dough stage had higher levels of crude protein (3.79), metabolizable energy (7.64), and digestibility (52.37), while mature stover stage showed higher fiber. In general, forages harvested at the soft doughhad better nutritional quality and lower fiber levels than those harvested at the mature stover. After 120 days of ensiling, the combination of molasses and salt as additives improved the best fermentation profile, characterized by lower pH, higher lactic acid production, reduced microbial spoilage (yeasts, molds, and aerobic flora), and improved nutritive value compared to control silages. The study concludes that harvesting sorghum at the soft dough stage and treating it with molasses plus salt enhances silage quality, offering a viable strategy for improving livestock feed and addressing fodder shortages in Burkina Faso

Mots-clés

additives, Burkina Faso, fermentation, growth stage, silage, sorghum.