Climate change and socio-economic challenges require greater production efficiency in the agricultural sector. Using microbial additives and biodiesel byproducts in silage production improves quality, reduces losses, and adds value to agro-industrial byproducts, thereby reducing environmental impacts. This study aimed to evaluate the potential of including cottonseed cake (CSC) and microbial inoculant isolated from forage cactus on the fermentation profile and quality of forage sorghum silage. The experimental design used was a completely randomized design, with four treatments: Control: sorghum (SS); sorghum + 10% CSC (% natural matter) (SSCSC); sorghum + Weissella cibaria (SSWC); and sorghum + 10% CSC + W. cibaria (SSCSCWC). There were increases of 15.1% in lactic acid bacteria, 11.4% in dry matter, and 62.9% in crude protein for SSCSC than SS (p = 0.001). There was a decrease of 96.4% in effluent losses (p = 0.002) and 21.6% in acid detergent fiber content (p = 0.005) in SSCSCWC compared to SS. Including 10% CSC and Weissella cibaria in sorghum silage was effective in improving nutritional composition with increased protein content and reduced fermentation losses. The cottonseed cake inclusion promotes greater efficiency in sorghum silage production, which can result in higher profitability and sustainability.