This study determined whether Canopeo and GreenSeeker measurements in Megathyrsus maximus can estimate plant height, dry matter mass, morphological components, and content of crude protein and neutral detergent fiber at different days of growth. Five plots of 5 × 25m M. maximus grass were defined: subplots of 1×1m were evaluated every three days, in which the pasture shows 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 days of regrowth. The subplot was evaluated for canopy height and mass accumulation. The canopeo index (CI) obtained at a higher height was lower than those obtained at a smaller height. Higher measurement height increased the normalized difference vegetation index (NDVI) relative to 0.10 m. The highest indexes were observed since 18 d of regrowth. Except for the CI evaluated at 0.10 m of height, the indexes were not correlated to the chemical composition of the forage. The CI and NDVI were positively correlated to plant height, dry matter mass, and leaf index, whereas both were negatively correlated with stalk index. Thus, lower evaluation heights for CI and NDVI can be a good predictor of forage height. Values of 0.83 and 85.8 for NDVI and CI, respectively, indicated an appropriate time to start the grazing of M. maximus.

The aim of this study was to determine, through meta-analysis, the effects of malic acid/malate addition on ruminal and blood parameters and diet digestibility in cattle. The literature search was conducted in Web of Science, Science Direct, and Google Scholar using the terms “organic acids”, “malic acid”, “malate”, and “bovine”. The database was composed of papers published between 1980 and 2023. The average effect of malate/malic acid inclusion was calculated using the “DerSimonian and Laird” random effects model. Meta-regression and subgroup analyses were conducted to explore sources of heterogeneity. Overall, malic acid (MAC) addition did not significantly affect rumen pH (ES = 0.310, p = 0.17), but subgroup analysis showed that malate increased pH (ES = 1.420, p < 0.01). MAC increased rumen propionate (ES = 0.560, p < 0.01) and total volatile fatty acids (VFAs; ES = 0.508, p = 0.03), while reducing the acetate-to-propionate ratio (p < 0.01). Starch and NDF intake were significant covariates affecting pH and VFA-related variables. MAC improved total-tract digestibility of dry matter (DM; ES = 0.547, p ≤ 0.05), crude protein (CP; ES = 0.422, p ≤ 0.05), and acid detergent fiber (ADF; ES = 0.635, p ≤ 0.05). It increased glucose levels (Overall ES = 0.170, p = 0.05) and reduced NEFA (Overall ES = −0.404, p = 0.03). In conclusion, the effectiveness of MAC depends on its chemical form. Improvements in rumen pH, fiber degradation, and blood parameters suggest more efficient energy use and potential metabolic benefits. The influence of diet-related covariates suggests that the response to MAC may vary depending on the nutritional composition of the diet.

Lemongrass essential oil (LEO) has been evaluated as a silage additive to improve silage fermentation and reduce fermentative losses. The present study aimed to evaluate the effects of increasing levels of LEO on whole-plant sorghum silage (WPSS) fermentation profile, fermentation losses, chemical composition, dry matter (DM) and neutral detergent fibre (NDF) in vitro degradation and aerobic stability. Five cultivars and fifty experimental silos were used to evaluate the following LEO levels: 0, 1, 2, 3 and 4 ml kg⁻¹ DM of WPSS. The material was compacted (650 kg m⁻²) and the silos were sealed, weighed and stored at room temperature for 167 days. The addition of LEO linearly decreased butyric acid content and the ratio between lactic and acetic acids. Intermediate levels of LEO increased NH₃-N and reduced lactic and acetic acids content. LEO linearly decreased silage gas losses. However, LEO did not affect total silage losses and DM recovery. Intermediate levels of LEO addition decreased organic matter and crude protein in the WPSS. The addition of LEO did not affect other chemical composition parameters, DM and NDF in vitro degradation, and pH and temperature of the silage after aerobic exposure. Thus, LEO supply in WPSS reduces gas losses, butyric acid concentration, and the ratio between lactic and acetic acids. However, LEO does not improve the chemical composition, in vitro degradation, and aerobic stability of WPSS.

Ensilage of rehydrated corn kernels (RC) has been used to improve nutritional value and facilitate on-farm storage. This study evaluated the effects of chitosan and lactic acid microbial inoculants on rehydrated corn silage microbiology, fermentation profile and losses, chemical composition, in vitro degradation, and aerobic stability. Forty experimental silos were used in a completely random design to evaluate the following treatments: 1) Control (CON): RC silage without additives; 2) Chitosan (CHI): RC silage with 6 g/kg dry matter (DM) of chitosan; 3) Lactobacillus buchneri (LB): RC ensiled with 5 × 10⁵ colony forming units (CFU) of L. buchneri per gram fresh weight; and 4) Lactobacillus plantarum and Pediococcus acidilactici (LPPA): RC ensiled 1.6 × 10⁵ of L. plantarum and 1.6 × 10⁵ P. acidilactici per gram fresh weight. Additives increased lactic acid bacteria and concentration of lactic and propionic acid, decreased mold and yeast count and gas and fermentative losses, and improved DM recovery. The CHI-silos had lower silage pH, Ammonia-N concentration, fermentative losses, and higher acetic acid concentration compared to microbial inoculated-silos. In addition, CHI and LB decreased silage pH and temperature after aerobic exposure. Although, treatments showed slight effects on the nutritional value of RC, CHI improved aerobic stability and decreaseds fermentation losses.

Fiber fragility is defined as the particle size reduction rate during chewing and can help to explain the effects on feed intake and animal performance of different fiber sources. This study aimed to estimate the fiber fragility of corn silage and cool-season pasture based on their chemical composition. Between June and December 2022, 25 samples of corn silage and 25 samples of cool-season pasture were collected from dairy farms in the state of Rio Grande do Sul. The samples were analyzed for particle size distribution, chemical composition, and fiber fragility. Contents of dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and fiber fragility were greater in corn silages compared to cool-season pasture. However, the ADF–NDF ratio was similar in forages. Crude protein (CP) content and the in situ degradation of DM and NDF were greater in cool-season pasture than corn silage. Dry matter and NDF in situ degradation were negatively correlated with increased contents of ADF, NDF, and ADL and the ADF–NDF ratio in forages. Fiber fragility was negatively correlated with DM degradation and positively correlated with contents of ADF, NDF, ADL, and DM. Fiber fragility decreased as CP content increased. Thus, greater fiber fragility may jeopardize nutrient degradation, and levels of fiber fragility are directly associated with fiber content.

Context: The ensiling process presents losses that are associated with the fermentative profile, resulting in lower nutritional value, and lower aerobic stability of silages. Aims: This study aimed to evaluate the effects of chitosan and microbial inoculants addition in Mombasa grass (Megathyrsus maximus) silage (MGS) fermentation profile and losses, chemical composition, in situ degradation, and aerobic stability. Methods: Forty experimental silos (PVC tubing with 28-cm inner diameter and 25-cm height) were used in a randomised block (n = 5) design to evaluate the following treatments: (1) MGS without additives (control, CON); (2) MGS treated with 5.0 × 104 colony-forming units (CFU) of Lactobacillus buchneri (NCIM 40788) per gram of fresh matter (LBB); (3) MGS treated with 1.6 × 105 CFU of L. plantarum and 1.6 × 105 CFU of Pediococcus acidilactici per gram of fresh matter (LPP); and (4) MGS treated with 6 g/kg DM of chitosan (CHI). Key results: The treatments did not alter the pH, ammonia-N, butyric, and lactic acid concentrations in the silage. The use of LPP reduced the ethanol content, while CHI increased propionic and branched-chain fatty acids compared with other treatments. Fermentation losses and dry-matter recovery were not affected by treatments. Chitosan reduced the organic matter of the MGS in relation to the other treatments, without having an impact on the other variables of chemical composition. The treatments did not influence the in vitro degradation, nor the pH and temperature after aerobic exposure of the silage. Conclusions: Chitosan increases ethanol compared with homofermentative lactic acid bacteria inoculation and does not affect ammonia-N of Mombasa grass silage. In addition, chitosan and microbial inoculants have limited effects on Mombasa grass silage fermentation losses, nutritional value, and aerobic stability. Implications: Chitosan does not reduce fermentation losses or improve the nutritional value of grass silage.