Determination of Nutritional Quality and Aerobic Stability of Sorghum, Maize, and Sorghum-Maize Mixture Silages

Abstract

The current study aimed to determine the nutritional quality and aerobic stability of sorghum, maize, and their mixture silages without any additives. Sorghum and maize were harvested at dough stage from a local farm in Tekirdag. Fresh plant materials were chopped to a length of 2-3 cm and packed into polythene bags, and vacuumed. A total of 12 vacuum-packed silos (4 replications in each treatment) were prepared with sorghum (S), maize (M), and a mixture of sorghum-maize (SM) forage (w:w, 50:50 according to dry matter) and stored at room temperature for 60 days. The chemical and microbiological composition of silages with the rate of aerobic deterioration upon aerobic exposure were evaluated. Based on the pH and ammonia nitrogen concentration, all silages could be classified as good quality. The water-soluble carbohydrate level of the SM group increased due to mixing S and M forages, leading to improved lactic acid content. The NDF and ADF values of silages varied between 520.52-588.32 and 234.98-309.01 g kg(-1), and the differences between silages were significant (P<0.01). The Hemicellulose/Cellulose ratio of S, M, and SM silages were found 0.94, 1.49, and 1.18, respectively. The lactobacilli and yeast content of silages were significant and varied between 5.18-7.41 and 5.18-7.29 log cfu g -1 , and the highest and lowest values were observed in SM and S silages, respectively (P<0.01). No visible mold was detected in all silages after 5 days of aerobic exposure (P>0.05). The pH, CO2, and yeast numbers were varied in groups between 4.88-6.74, 55.71-119.33 g kg(-1), and 8.40-9.01 log cfu g(-1). It was concluded that it is possible to improve the nutritional and fermentation characteristics of sorghum and maize silage by ensiling their mixture. However, it is highly recommended that silage additives should be used to guarantee and strengthen the fermentation and aerobic stability of silage mostly made by a mixture of these two energetic forage crops.