Organic Acids as Silage Additive: Effects on Fermentation Dynamics and Aerobic Stability of Sorghum Silage and Performance of Growing Cattle

This study aimed to evaluate the effect of organic acids on fermentation characteristics and aerobic stability of silage and performance of growing cattle. Sorghum fodder either ensiled without organic acid (Sc) or with 0.50% formic acid (S_0.5%FA), 0.50% propionic acid (S_0.5%FA) and 0.25% combination of formic and propionic acid (S_{0.25%FA+0.25%PA}). Twenty-Four Sahiwal heifers were randomly allocated into four groups (n=6) on body weight (117±5.0 kg) and age basis (10±2.0 months). The heifers either received a basal diet having silage without additives (S_C) or were fed on diet having three silages preserved with 0.5% formic acid (S_0.5%FA), 0.5% propionic acid (S_0.5%FA) or 0.25% formic acid and 0.25% propionic (S_{0.25%FA+0.25%PA}). Silages in all the groups were well preserved, as indicated by high lactic acid content and low pH value, ammonia-nitrogen and butyric acid contents. S_0.5%PA silage showed better (P<0.05) aerobic stability. Treatments had no adverse effect on dry matter intake and nutrients digestibility while average daily gain was greater (P<0.05) in S_0.5%FA group. There was no difference in plasma total protein, albumin, non-esterified fatty acid and beta-hydroxybutyric acid levels. The plasma urea nitrogen, glucose and cholesterol were higher (P<0.05) in S_0.5%PA group. Treatments had no effect on triiodothyronine (T₃) but tetraiodothyronine (T₄) and insulin like growth factor-1 were higher in S_0.5%FA group. The findings of this study revealed that feeding silage preserved with formic and propionic acid alone or in combination had no adverse effect on feed intake and nutrient digestibility while growth performance was better in the cattle fed on 0.5% formic acid added silage.