To better understand the ensiling characteristics of sorghum stalk, the dynamic changes of fermentation parameters, nutrient components and bacterial community of sorghum stalk silage were analyzed by intermittently sampling on day 0, 1, 3, 7, 14, 28, and 56 of ensiling duration. The results showed that high-moisture sorghum stalk was well preserved during ensiling fermentation, with the DM loss of 4.10% and the little difference between the nutrients of sorghum stalk before and after ensiling. The pH value of silage declined to its lowest value of 4.32 by Day 7 of ensiling, and other fermentation parameters kept steady since Day 28 of ensiling. The amplicon sequencing analysis revealed that the alpha diversity parameters of silage bacterial community including Shannon index, observed features, Pielou evenness and Faith PD gradually declined (P < 0.01) with ensiling duration. Principal coordinate analysis (PCoA) revealed that bacterial profiles of raw material would experience a succession becoming a quite different community during ensiling fermentation. Taxonomic classification revealed a total of 10 and 173 bacterial taxa at the phylum and genus level, respectively, as being detected with relative abundances higher than 0.01% and in at least half samples. LEfSe analysis revealed that 26 bacterial taxa were affected by sampling timepoint (P < 0.05 and LDA score > 4). When focusing on the dynamic trend of silage bacterial taxa, lactic acid bacteria successfully dominated in the bacterial community on Day 1 of ensiling, and the bacterial community almost came to a plateau by Day 28 of ensiling, with Lactobacillus and Leuconostoc as the dominant genera. In a word, the succession of fermentation parameters, nutrient components and bacterial community indicate a successful dominance establishment of LAB and a fast advent of fermentation plateau, suggesting that high-moisture sorghum stalk can be ensiled directly, but the pH of mature silage is a little high.

To investigate the source of the bitter almond taste in whole corn silage (WPCS), headspace solid-phase microextraction combined with gas chromatography–mass spectrometry (HS-SPME-GC-MS), headspace gas chromatography–ion migration spectrometry (HS-GC-IMS), and electronic nose (E-nose) technology were employed. The study analyzed the differences in volatile compounds between two WPCS samples with distinct odors from the same cellar. GC-IMS and GC-MS identified 32 and 101 volatile organic compounds (VOCs), respectively, including aldehydes, alcohols, esters, ketones, and other compounds. Three characteristic volatile organic compounds associated with the bitter almond taste were detected: benzaldehyde, cyanide, and isocyanate. The electronic nose demonstrated varying sensitivities across its sensors, and principal component analysis (PCA) combined with variable importance projection (VIP) analysis revealed that W5S (nitrogen oxides) could differentiate between the two distinct silage odors. This finding was consistent with the GC-MS results, which identified 34 nitrogen-containing heterocyclic compounds in the abnormal silage sample, accounting for 77% of the total nitrogen-containing compounds. In summary, significant differences in aroma composition were observed between the bitter almond-flavored silage and the other silage in the same cellar. These differences were primarily attributed to changes in volatile organic compounds, which could serve as indicators for identifying bitter almond-flavored silage.

Forage scarcity in semi-arid regions necessitates the identification of optimal sorghum cultivars for high-quality silage production. This study systematically evaluated varietal differences in agronomic characteristics, nutritive value, fermentation quality, and bacterial community structure of whole-plant sorghum silage. A completely randomized design was implemented with four sorghum cultivars representative of semi-arid northwestern China: Liaotian1 (LT1), Jinnuo3 (JN3), Jinza2001 (JZ2001), and Jinza1531 (JZ1531). Five quadrats per cultivar in experimental fields were randomly designated as biological replicates for silage production. The plants were harvested at the dough stage, chopped, and ensiled in laboratory-scale silos (n = 20, 4 cultivars × 5 replicates) for 120 days. Analyses included agronomic measurements, chemical composition, fermentation parameters, microbial plate enumeration, and bacterial community profiling via 16S rRNA gene amplicon sequencing of the V3–V4 hypervariable region. The results showed that cultivar significantly influenced (p < 0.01) all agronomic traits and most nutritional parameters. The forage-type cultivar LT1 showed the highest biomass yield but the lowest nutritional quality, with higher neutral detergent fiber (47.77% vs. 29.21–32.35%; p < 0.05) and lower starch (10.94% vs. 18.10–24.30%; p < 0.05) contents as well as higher dry matter losses (1.39% vs. 0.91–1.23%; p < 0.05) than grain-type cultivars. In contrast, the grain-type cultivar JN3 exhibited balanced yield-quality traits with the highest (p < 0.05) starch (24.30%) and crude protein (7.50%) contents. Most fermentation parameters differed significantly (p < 0.01) among cultivars, with JN3 showing elevated ammonia-nitrogen (0.24 g/kg) but within acceptable ranges. Microbial diversity analysis revealed cultivar-driven differences in bacterial communities, with JN3 enriched in Leuconostoc and early-colonizing taxa (p < 0.05 and LDA Score > 4). It is concluded that the grain-type cultivar JN3 is the most suitable cultivar for whole-plant sorghum silage production in water-limited regions due to its optimal yield-quality balance. The findings underscore the importance of integrated cultivar evaluation and suggest the potential of targeted microbial inoculants for enhancing silage quality.

Genomic selection (GS) plays a crucial role in livestock breeding. However, its implementation in Chinese beef cattle breeding is constrained by a limited reference population and incomplete data records. To address these challenges, this study aimed to identify more effective models for multi-population genomic selection. We simulated five different beef cattle populations and selected three populations with varying levels of kinship to investigate the impact of population relationships on genomic prediction. Utilizing results from a genome-wide association study (GWAS), we preselected different proportions of single nucleotide polymorphism (SNP). Subsequently, we employed three models—genomic best linear unbiased prediction (GBLUP), multi-genomic best linear unbiased prediction (MGBLUP), and weighted multi-genomic best linear unbiased prediction (WMGBLUP)—for within-population and multi-population genomic prediction. Our results showed that increasing the size of the training set improved within-population prediction accuracy. Furthermore, both MGBLUP and WMGBLUP outperformed GBLUP in terms of prediction accuracy for both within-population and multi-population analyses. Among the models evaluated, the WMGBLUP model, which utilized the top 5% of preselected SNPs based on GWAS findings, demonstrated superior performance, yielding an improvement of up to 11.1% in within-population prediction and 16.5% in multi-population prediction. In summary, both WMGBLUP and MGBLUP models exhibit enhanced efficacy in improving genomic prediction accuracy, and the incorporation of GWAS results can further optimize their performance.

The present experiment aimed to investigate the effects of harvest stages on the fermentation quality and nutritional value of sorghum stalk silage. Sorghum stalks were harvested at the three stages (milk, dough, and ripe), chopped, and ensiled for 60 d. Each treatment had five replicates, and the silages were evaluated for fermentation quality, nutritional composition, in vitro rumen fermentation characteristics, and bacterial community profiles. The results showed that the crude protein, neutral detergent fiber, and acid detergent fiber contents decreased significantly with harvest maturity (p < 0.05). Consequently, silage from the ripe stage possessed the highest dry matter, relative feed value, and total digestible nutrients (p < 0.05). In vitro rumen fermentation indicated that the ripe stage silage exhibited the greatest gas production, and the lowest concentrations of ruminal ammonia–nitrogen (p < 0.05). Microbial analysis revealed a shift from dominant epiphytic Proteobacteria to fermentative Firmicutes post-ensiling, with the ripe stage community co-dominated by Lactobacillus and Leuconostoc, in contrast to the milk stage’s enrichment with Klebsiella. In conclusion, harvesting sorghum at the ripe stage is the optimal strategy as it establishes a beneficial microbial community, resulting in silage with superior nutritional value and rumen fermentation efficiency.