This study investigates the genetic structure of Belgian Red (BR), Belgian Red and White (BWR), and Qinchuan (QinC) cattle, with a focus on identifying genes associated with reproductive functions, growth, and development. A total of 270 Belgian cattle (91 BR and 179 BWR) and 286 Qinchuan cattle were genotyped using the Illumina Bovine SNP 50K microarray. Data analysis was conducted using PLINK and Beagle 5.1 to estimate linkage disequilibrium (LD) and effective population size (Ne). Candidate SNP loci were identified by selecting the top 5% based on the weighted fixation index (Fst) and nucleotide diversity (θπ ratio), followed by gene annotation. The analysis revealed 160 candidate genes under selection between Qinchuan and Belgian Red cattle, and 98 candidate genes between Qinchuan and Belgian Red and White cattle. Key genes associated with reproductive functions, including NFKBIA, PTHLH, UGT2B10, TRPC4, and ALOX5AP, were identified. Additionally, genes involved in growth and muscle development were highlighted, particularly those influencing protein synthesis, fatty acid metabolism, and collagen synthesis. These findings provide valuable molecular markers for enhancing reproductive efficiency, growth, and meat production through genetic selection and selective breeding strategies.

Objective: The X/Y sperm separation technique plays a crucial role in gender control. The objective of this experiment is to investigate the effect of polyvinylpyrrolidone (PVP) concentration (A: 0%, B: 1%, C: 3%, D: 5%, E: 7%, vol/vol) on Y sperm sorting efficiency, based on the specific binding of Resiquimod (R848) to toll-like receptor (TLR)7/8 receptors on the tail of X sperm.Methods: The different concentrations of PVP were added to the R848 sperm sorting solution to facilitate the separation of Y sperm. Subsequently, the isolated sperm were subjected to quantification and motility assessment using computer-assisted semen analysis system. The X/Y sperm ratio is then analyzed by flow cytometry. The sorted sperm were evaluated for acrosomal and plasma membrane integrity. The spermatozoa were then subjected to immunofluorescent staining through immunofluorescence (IF) techniques, which preceded the quantification of the negative sperm rate. The proportion of male embryos was determined through embryonic sex identification after in vitro fertilization.Results: Flow cytometry analysis results showed that when the PVP concentrations were 3%, 5% and 7%, the proportion of Y sperm was not statistically significant, (p≥0.05). However, these percentages were significantly elevated compared to those obtained with 0% and 1% PVP concentrations (p<0.05). The IF staining results demonstrated that the proportion of TLR7/8-negative sperm remained statistically unchanged across PVP concentrations of 3%, 5%, and 7% (p≥0.05). However, these percentages were significantly elevated compared to those obtained with 0% and 1% PVP concentrations (p<0.05). The generation of male blastocysts was significantly higher at a PVP concentration of 3% compared to 0% and 1% (p<0.05), but showed no significant difference from 5% and 7% (p≥0.05).Conclusion: Selecting a 3% PVP concentration not only ensures sufficient sperm yield but also promotes effective selection of Y-sperm. These findings provide empirical evidence supporting the high-efficiency separation of X/Y sperm in livestock.

The maturation of oocytes is a critical step in mammalian reproduction, involving dynamic regulation of gene expression. Therefore, investigating how gene expression varies during different stages of oocyte maturation is highly important. This study employed single-cell RNA sequencing (scRNA-seq) to analyze bovine oocytes at the germinal vesicle (GV) and metaphase II (MII) stages. The results identified 1787 differentially expressed genes (DEGs) between the two stages, with 1556 genes upregulated and 231 downregulated in the GV stage. Further investigation using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that the upregulated genes are mainly involved in mitochondrial functions and energy metabolism, whereas the downregulated genes are primarily associated with signaling pathways. Validation through RT-qPCR confirmed that COA4, TKT and GPX4 were significantly higher in GV-stage oocytes, while ISG15, MAP1LC3C and ZEB2 were notably downregulated. This study highlights significant gene expression differences between GV and MII bovine oocytes, underscoring the vital roles of genes related to energy metabolism and signaling during oocyte maturation. The expression patterns of these genes provide important molecular markers for further elucidating the mechanisms underlying oocyte maturation.

Objective: Semen quality plays a crucial role in embryo formation in cattle. This study aims to compare the effects of 0°C refrigerated semen and liquid nitrogen-frozen semen on the quality of in vitro fertilized embryos in Simmental cattle.Methods: Semen from six bulls was devidedt equally into two groups. One was diluted with cold storage solution and stored at 0°C for 72 h; the other with cryopreservation solution and preserved in liquid nitrogen for 72 h. Post-storage, sperm quality (motility, progressive motility via computer-assisted sperm analysis, and acrosome/plasma membrane integrity) was assessed, along with malondialdehyde, reactive oxygen species, adenosine triphosphate, and mitochondrial membrane potential levels. For in vitro fertilisation (IVF), oocytes from Simmental cows (>50 per group) were inseminated with the two semen groups. At 45 h post-IVF, embryo cleavage rate was recorded; on day 8, blastocyst rate was determined. Embryos then underwent BrdU staining (proliferation) and TUNEL staining (apoptosis), with proliferation and apoptosis levels quantified via marker genes.Results: The results showed that compared with liquid nitrogen-frozen semen, 0°C refrigerated semen exhibited significantly higher sperm motility, forward motility rate, acrosome integrity, and plasma membrane integrity (p<0.05). in vitro fertilized embryos also exhibited significant increases in quality and quantity (cleavage rate and blastocyst rate) (p<0.05), and embryos derived from 0°C refrigerated semen contained significantly more proliferating cells (p<0.05) and fewer apoptotic cells (p<0.05) than those from frozen semen.Conclusion: These findings suggest that 0°C refrigerated semen is superior to liquid nitrogen frozen semen in terms of sperm quality parameters and in vitro embryo development.

Background: Chinese Red Steppe cattle (CRS) combine indigenous environmental resilience with moderate dairy performance, whereas Holstein cattle (HOL), despite their high milk yield, suffer reduced genetic diversity and compromised adaptation. A comparative analysis of their population genetic architecture and selection signatures can reveal valuable targets for CRS dairy improvement. Methods: We genotyped 61 CRS and 392 HOL individuals using the Illumina GGP Bovine 100K SNP array and performed stringent quality control. Population structure was assessed via principal component analysis, neighbor-joining trees, and sparse nonnegative matrix factorization. Historical effective population size (Ne) and divergence time were inferred with SMC++. Genome-wide selection scans combined Fixation Index (FST) and Cross-Population Composite Likelihood Ratio test (XP-CLR); overlapping high-confidence regions were annotated and subjected to GO and KEGG enrichment analyses. Results: CRS and HOL were clearly separated along PC1 (explaining 57.48% of variance), with CRS exhibiting high internal homogeneity and weak substructure, versus greater diversity and complex substructure in HOL. SMC++ indicated a split approximately 3500 years ago (700 generations) and a pronounced recent decline in Ne for both breeds. Joint selection mapping identified 767 candidate genes; notably, the ACSM1/2B/3/4 cluster on chromosome 25—key to butanoate metabolism—showed the strongest signal. Enrichment analyses highlighted roles for proteasome function, endoplasmic reticulum stress response, ion homeostasis, and RNA processing in regulating milk fat synthesis and protein secretion. Conclusion: This study delineates the genetic divergence and demographic history of CRS and HOL, and pinpoints core genes and pathways—particularly those governing butanoate metabolism and protein quality control—underlying dairy traits. These findings furnish molecular markers and theoretical guidance for precision breeding and sustainable utilization of Chinese Red Steppe cattle.