Evaluation of silage quality of three sorghum varieties using in livestock systems of Burkina Faso.

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Résumé

This study aims to evaluate the physicochemical, microbiological and nutritional quality of silage from three improved sorghum varieties (Sariaso 14, Sariaso 15 and Sariaso 16) used in livestock farming systems in Burkina Faso. The sorghum stover were harvested after the grain harvest and ensiled with four treatments: without additives, with molasses, with salt, and with molasses + salt for 120 days. After 120 days, the fermentation parameters differed according to the varieties and additives. The pH of the silages ranged from 3.71 to 4.64, with the lowest values observed in Sariaso 16 ensiled with salt. The highest titratable acidity (18.36 g/kg DM) was obtained in the molasses + salt treatments, indicating more intense fermentation. From a microbiological perspective, the aerobic bacteria loads were lowest in molasses + salt silage (3.41×10⁶ CFU/g DM) compared to the control (1×10⁸ CFU/g FM). In addition, there was a reduction in yeasts and moulds, especially in the molasses + salt treatment (4.06×10⁵ CFU/g FM). Bromatological analysis showed significant differences (p<0.05) between varieties and treatments. Sariaso 16 sorghum stalks treated with molasses/molasses + salt had the best nutritional values: high crude protein (3.33–3.41% DM), higher metabolisable energy (≈7.5 MJ/kg DM) and high digestibility (IVDOM > 51%). The results of the study show that improved varieties, particularly Sariaso 16, combined with the use of additives, are an effective strategy for producing high-quality silage. These results also demonstrate that variety selection, combined with the addition of additives, is a major lever for optimising the quality of sorghum silage and securing feed for ruminants during the dry season in Burkina Faso’s livestock systems.

Mots-clés

Sorghum bicolor, Livestock, Silage, Quality, Sorghum varieties