Search

This study determined the effectiveness of two Lactobacillus buchneri strains (commercial and indigenous) and sodium benzoate ( SB) in improving the aerobic stability of corn silage under laboratory and field conditions. Two experiments were carried out to test the following treatments: untreated forage, commercial L. buchneri ( CLB), indigenous L. buchneri ( ILB) and SB at a 2 g kg−1 concentration. Both inoculants were applied at a rate of 1 × 106 colony forming units of bacteria per gram of forage. In experiment 1, five replicates of each treatment were ensiled in 15-L laboratory silos. The nutritional, fermentation and microbiological characteristics and aerobic stability of the silage were determined. In experiment 2, the top of a bunker silo was divided into four parts (blocks) along its length before it was sealed, and the treatments were randomly applied. Three bags were buried in each experimental unit (two at the top and one at the core) to determine the loss of dry matter ( DM) and the silage characteristics. In experiment 1, ILB exhibited a lower lactic acid concentration and higher 1,2-propanediol and acetic acid levels, which provided intermediate aerobic stability (67 h). In both experiments, treatment SB exhibited higher residual water-soluble carbohydrate levels and longer aerobic stability relative to the other treatments. In experiment 2, there were lower DM losses and higher digestibility coefficients when SB was applied, similar to that found at the core. Overall, SB was the most effective additive for improving fermentation, preserving nutrients and reducing the aerobic deterioration of corn silage at the top of a bunker silo in a hot-climate environment. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of a blend of different sources of magnesium oxide associated or not with monensin, on productive, ruminal, and nutritional parameters of steers. Eighty-four Nellore steers with an initial body weight (BW) of 367.3 ± 37.9 kg were allocated to one of 28 pens, with three steers per pen. Each pen was considered an experimental unit. Using a completely randomized design with a 2 × 2 factorial arrangement, the following treatments were assigned to each pen: 1) Control (CON)-a basal diet without additive inclusion; 2) Magnesium oxide blend (MG)-basal diet plus a magnesium-based product (pHix-up, Timab Magnesium, Dinard, France) provided at 0.50% of dry matter (DM); 3) Monensin (MON)-basal diet plus 25 mg/ kg of DM of sodium monensin (Rumensin, Elanco Animal Health, Greenfield, IN); and 4) MG association with MON-basal diet plus MG + MON, at the same doses of the individual treatments. The experimental period lasted 100 d. Blood samples were collected on days 0, 13, and 70 to determine d-lactate levels. Daily feed intake was recorded, and animal ingestive behavior was visually observed on days 66 and 67. On day 70, skeletal muscle tissue samples were obtained through biopsy for gene expression analysis. At the end of the experimental period, carcass ultrasonography was conducted. Subsequently, the steers were slaughtered, and rumen epithelium samples were collected for morphometric analysis. The use of monensin, of magnesium oxide blend, and their interactions, were treated as fixed effects, while the pens were considered as a random effect. Statistical differences were considered when P  < 0.05. Steers-fed MG-containing diets consumed approximately 0.6 kg more DM per day than those fed diets without this additive ( P  = 0.01; 11.3 vs. 11.9 kg/d). The inclusion of MG in the diet increased ( P  = 0.02) the average daily gain. There was a greater Longissimus muscle area (LMA) and LMA per 100 kg of BW ( P  ≤ 0.03) for steers-fed diets with MG. Steers-fed MON exhibited reduced mRNA expression of the Atrogin-1 and mTOR compared to steers-fed MG + MON diets (MON × MG: P  ≤ 0.04). Steers-fed MON had 6.9% greater feed efficiency ( P  = 0.02). Papillae width was lesser for CON than other treatments (MON × MG: P  = 0.02). In conclusion, the magnesium oxide blend improved performance and carcass traits in high-energy feedlot diets, while monensin enhanced feed efficiency, suggesting potential for their use as alternatives or complements in beef cattle nutrition., Competing Interests: The authors declare no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)