Since milk yield is a highly important economic trait in dairy cattle, the genome-wide association study (GWAS) is vital to explain the genetic architecture underlying milk yield and to perform marker-assisted selection (MAS). In this study, we adopted a haplotype-based empirical Bayesian GWAS to identify the loci and candidate genes for milk yield. A total of 1 092 Holstein cows were sequenced by using the genotyping by genome reducing and sequencing (GGRS) method. After filtering, 164 312 high-confidence SNPs and 13 476 haplotype blocks were identified to use for GWAS. The results indicated that 17 blocks were significantly associated with milk yield. We further identified the nearest gene of each haplotype block and annotated the genes with milk-associated quantitative trait locus (QTL) intervals and ingenuity pathway analysis (IPA) networks. Our analysis showed that four genes, DLGAP1, AP2B1, ITPR2 and THBS4, have relationships with milk yield, while another three, ARHGEF4, TDRD1 and KIF19, were inferred to have potential relationships. Additionally, a network derived from the IPA containing one inferred (ARHGEF4) and all four confirmed genes likely regulates milk yield. Our findings add to the understanding of identifying the causal genes underlying milk production traits and could guide follow up studies for further confirmation of the associated genes, pathways and biological networks.

The objective of this study was to screen probiotic lactic acid bacteria (LAB) with beneficial properties such as acid and bile salt tolerance, antibacterial activity, autoaggregation ability, and cholesterol‐lowering capacity from fermented Cornus officinalis fruits. Eleven probiotic LAB strains, identified as ten Lactobacillus plantarum and one Lactobacillus casei, were screened out and evaluated by in vitro tests. The results of principal component analysis (PCA) based on probiotic characteristics suggested that L. plantarum 2519, 3725, and 3735 were promising probiotic candidates, which were better than the probiotic reference strain, Lactobacillus rhamnosus GG. Among them, L. plantarum 2519 showed the hightest autoaggregation value of 94.62%, and L. plantarum 3725 showed a cholesterol assimilation percentage of 47.83% and remarkable antimicrobial activity against five foodborne pathogens with the cell number decrease from 3.68 to 4.60 log cfu/mL. These results indicate that these three LAB strains are good candidates as probiotic starters. Practical applications Cornus officinalis is known as a kind of medicinal plant with fruits having many pharmacological activities, such as improving liver and kidney function, potent hpyerglycemic and antioxidant effect. C. officinalis is rich in endophytes, and its pharmacological activities may be associated with the metabolic products of endophytic bacteria. Therefore, the exploitation of microbial resources in spontaneous fermented C. officinalis fruits is beneficial to select probiotics. Moreover, the fruits from a natural reserve should be an excellent resource, attributing to the low impact of antimicrobial contamination may guarantee non or low intensity of antibiotic activity of their endophytic bacteria.