Based on our results of genome-wide association analysis, we performed gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis; three candidate genes (ABCG2, CD44, SPP1) were screened in this study for SNPs association analysis with production traits in 999 Holstein cattle. In this research, flight mass spectrometry genotyping was used to detect the polymorphism of SNP seats. It was shown that four, four, and two single nucleotide polymorphisms (SNP) loci were detected for the ABCG2, CD44, and SPP1 genes, respectively, and the different genotypes of these 10 SNPs significantly affected the milk production performance of Chinese Holstein cattle in terms of milk yield, milk fat percentage, milk protein percentage, somatic cell score, and urea nitrogen content. Among them, ABCG2-G.80952G > T locus, ABCG2-G.120017G > A locus and CD44-G.2294G > C locus had significant effects on somatic cell score (p < 0.01). Cows with GG genotypes at ABCG2-G.80952G > T locus, AA and GG genotypes at ABCG2-G.120017G > A locus, and GG genotypes at CD44-G.2294G > C locus had lower somatic cell scores. The present study elucidated that ABCG2, CD44, and SPP1 could be selected for marker-assisted selection and will benefit for future precise molecular breeding.

Meat quality and meat composition are not separated from the influences of animal genetic improvement systems; the growth and development of skeletal muscle are the primary factors in agricultural meat production and meat quality. Though the muscle-type cofilin (CFL2) gene has a crucial influence on skeletal muscle fibers and other related functions, the epigenetic modification mechanism of the CFL2 gene regulating meat quality remains elusive. After exploring the spatiotemporal expression data of CFL2 gene in a group of samples from fetal bovine, calf, and adult cattle, we found that the level of CFL2 gene in muscle tissues increased obviously with cattle age, whereas DNA methylation levels of CFL2 gene in muscle tissues decreased significantly along with cattle age by BSP and COBRA, although DNA methylation levels and mRNA expression levels basically showed an opposite trend. In cell experiments, we found that bta-miR-183 could suppress primary bovine myoblast differentiation by negatively regulated CFL2. In addition, we packaged recombinant adenovirus vectors for CFL2 gene knockout and overexpression and found that the CFL2 gene could promote the differentiation of primary bovine myoblasts by regulating marker genes MYOD, MYOG and MYH3. Therefore, CFL2 is an essential mediator for promoting myogenic differentiation by regulating myogenic marker genes in cattle myoblasts.

Reproductive traits are essential in dairy cattle breeding, and improving body conformation is considered beneficial for reproductive performance. This study systematically analyzed the genetic relationships between six key conformation traits—stature (ST), body depth (BD), loin strength (LS), rump angle (RA), rump width (RW), bone quality (BQ)—and reproductive performance in 1631 Jersey cattle from China. Heritability estimates for conformation traits ranged from 0.05 to 0.62. We identified significant phenotypic and genetic correlations between conformation and reproductive traits, and regression analyses confirmed the predictive value of conformation traits for reproductive outcomes. Genome-wide association studies detected 24 significant SNPs associated with ST, RW, RA, and BQ. Subsequent bioinformatics analysis revealed seven candidate genes (AZIN1, OR2H1, HS6ST3, ERCC4, KCNH5, KRT19, KRT35) involved in embryonic development and estrous cycle regulation. Notably, incorporating six SNPs, which are linked to these candidate genes, into genomic prediction models significantly improved the accuracy for predicting Age at First Calving (AFC) and Gestation Length (GL). These results elucidate the shared genetic basis of conformation and reproduction, providing theoretical support for using conformation traits in marker-assisted selection to enhance reproductive efficiency in Jersey cattle.

Bovine mastitis causes significant economic losses in the dairy industry. Emerging evidence highlights the critical role of long non-coding RNAs (lncRNAs) in inflammation-associated epigenetic regulation through competing endogenous RNA (ceRNA) networks. In this study, we established a bovine mastitis model in three healthy primiparous Holstein cows by intramammary infection with S. aureus. Infected and control mammary tissue samples were then collected for transcriptomic profiling, which identified 2005 differentially expressed lncRNAs. Among them, BMNCR was significantly upregulated in S. aureus-infected mammary tissues and S. aureus-stimulated BMECs. We evaluated the coding potential of BMNCR and confirmed its non-coding nature. Functional studies in BMECs demonstrated that knockdown of BMNCR suppressed proliferation, promoted apoptosis, and altered the expression of inflammatory factors, including IL-2, IL-6, IL-8, and IL-12. Mechanistically, BMNCR acted as a sponge for bta-miR-145, thereby leading to the derepression of ANO6. Silencing ANO6 partly recapitulated the effects of BMNCR knockdown, impairing proliferation and increasing IL-8 expression. Collectively, these findings suggest that the BMNCR/miR-145/ANO6 axis is involved in the regulation of inflammatory responses and epithelial homeostasis during bovine mastitis, with BMNCR functioning as a protective regulator in this process.

This study characterized the genetic basis of reproductive and calving traits in Jersey cattle at different physiological stages and identified potential candidate genes. After quality control, 2716 records were available for heifer reproductive traits, 2707 for multiparous cow reproductive traits, and 5423 calving records for calving ease (CE) and calf birth weight (CBW). CE and CBW were analyzed from the maternal perspective, with records assigned to the corresponding dams. Genetic parameters were estimated using AI-REML in DMU with animal, repeatability, and bivariate models. Genome-wide association analyses were performed using a mixed linear model based on 1,660,477 SNPs from 1578 genotyped Jersey cattle. Heritability estimates for age at first service (AFS) and age at first calving (AFC) were 0.416 and 0.380, respectively, whereas estimates for reproductive traits in multiparous cows were generally low (0.072–0.154). Calving interval (CI) and days open (DO) showed a strong positive genetic correlation (0.781). GWAS identified five significant loci associated with AFC, number of services per conception in heifers, CI, and dam-associated genetic variation in CE. Candidate genes included PIK3C2G, DGKI, ABCC1, CCDC85A, CRMP1, EVC, and EVC2. Exploratory KEGG enrichment suggested potential involvement of phosphatidylinositol signaling, Hedgehog signaling, ABC transporters, and inositol phosphate metabolism. Overall, reproductive traits showed distinct genetic characteristics between heifers and multiparous cows, and AFS and AFC exhibited relatively greater potential for genetic improvement. The identified genomic regions provide preliminary candidates for further validation and potential future application in genomic breeding.