Heat stress (HS) severely significantly reduces milk yield and causes substantial economic losses of dairy cows. TMT-based proteomes and an untargeted metabolomics approach were used to conduct the proteomics and metabolomics in heat-stressed (HS, n = 6) and heat-resistant (HR, n = 6) Chinese Holstein. The proteomics showed that 29 differentially expressed proteins (DEPs), with SERPINA3-7, ACTN4, and PLOD1 up-regulated, and GSN down-regulated in HR cows. The metabolomics showed that 168 differential positive metabolites and 170 differential negative metabolites were identified, with HR cows exhibiting lower levels of anti-inflammatory compounds, such as N6-Acetyl-L-lysine. In addition, 29 DEPs and 338 metabolites revealed four key pathways, including the lysine degradation (ko00310) and metabolic pathway (ko01100) with underlying protein–metabolite interactions, where up-regulated PLOD1 and ACTN4 and down-regulated EXT1 and GSN were observed to be interacting with the down-regulated N6-Acetyl-L-lysine, citric acid, 4-Pyridoxic acid, uracil, and uric acid, and the up-regulated arachidonic acid was enriched, which could be used for rapid and noninvasive screening of heat-tolerant cows. Functional validation through cell experiments, qPCR, and Western blot analyses showed that the interference of the ACTN4 gene could induce dairy cow mammary epithelial cell apoptosis, which could be regarded as a potential biomarker for HS in Chinese Holstein. Our results facilitate a better understanding of the molecular mechanism underlying the HS issue in dairy cows and provide a crucial insight into the alternative strategies to enhance animal welfare and productivity under high-temperature conditions.

Heat stress has detrimental effects on the production and reproduction of dairy cows. The present work reveals the role of differentially expressed (DE) miRNAs on the heat stress tolerance of bovine blood using RNA sequencing. Twelve dairy cows were divided into heat-resistant and heat-stressed groups according to rectal temperature and reduction of milk yield. Using the ACGT101-miR program, 1262 known miRNAs and 719 novel miRNAs were identified. Of the 719 novel miRNAs, 144 significantly DE miRNAs (67 up-regulated and 77 down regulated) (P < 0.05) were screened between heat-resistant and heat-stressed cows using edgeR software. Eleven high DE miRNAs (bta-miR-455-3p, bta-miR-455-5p, mmu-mir-6240, bta-miR-106b, bta-miR-11,971, bta-miR29a, bta-miR-142-5p, bta-miR-15b, bta-miR-342, bta-miR-32, and bta-miR-6524) were verified by qRT-PCR, an outcome which was consistent with the sequencing results. The target genes related to heat tolerance of the heat shock protein (HSP) family, malonyl CoA-acyl carrier protein transacylase (MACT), and prolactin receptor (PRLR), were predicted using the TargetScan and miRanda software. Furthermore, KEGG analyses with the R package OmicStudio and on the basis of DE miRNAs revealed an enriched MAPK signaling pathway, endocytosis, Th17 cell differentiation, cellular senescence, peroxisome, and Fc gamma R-mediated phagocytosis. These findings could help in screening for heat tolerance genes for improved dairy cow heat tolerance.

本文从牛奶产量、乳制品产量、生鲜乳价格、饲料行情、奶牛生产性能测定、规模化牧场建设等几个方面分析了2021年山东省奶业整体发展情况,探讨了当前奶业发展面临的问题,并结合山东省奶业现状提出了促进奶业持续、健康发展的建议.

A Correction to this paper has been published: https://doi.org/10.1038/s41467-021-21014-9

夏季高温对奶牛繁殖性能影响较大.当温湿度指数(THI)大于一定阈值时,奶牛就会产生热应激反应.缓解奶牛热应激是提高繁殖效率的关键,需要多种降温措施共同施行.本文介绍了牛体降温、合理饲喂、选择适合的公牛及采用同期发情等夏季提高奶牛繁殖力的措施,奶牛场可以结合本地气候情况选择使用.

F-box and WD-40 domain protein 11 (FBXW11) is an important component of the E3 ubiquitin-ligase enzyme that plays a key role in the ubiquitin-dependent regulation of spermatogenesis. In our previous research, the mRNA expression of FBXW11 in bull sperm with high motility is significantly higher than that with low motility. In the present study, the protein expression levels of FBXW11 in bull testicular tissues with low-performance sperm quality groups were significantly higher than those in normal performance groups. The immunohistochemistry result demonstrated that FBXW11 protein was located in the periphery of Leydig cells and seminiferous tubules. Three splice variants of the FBXW11 gene, namely, FBXW11-tv1, FBXW11-tv2, and FBXW11-tv3, were identified in testicular tissues. The splicing patterns of the three variants are exon skipping. The transcript FBXW11-tv2 expressions were the highest in each sample. The low-performance groups displayed higher FBXW11-tvl and FBXW11-tv2 transcript expressions than the normal performance groups. Two CpG islands were located within the 5' UTR and exon 1-2 region of the FBXW11 gene. Bisulfite sequencing PCR results demonstrated that the methylation levels of 11 methylation sites in the CpG island 2 from -99 to -43 in the normal performance groups were significantly lower than those in the low-performance groups. Pearson correlation analysis suggested that the CpG island 2 methylation level was negatively correlated with sperm motility and the transcript FBXW11-tv2 expression level. Our data revealed that alternative splicing and DNA methylation jointly regulated FBXW11 gene expression and were correlated with sperm quality traits during spermatogenesis in Holsteins.

Domestication and subsequent selection of cattle to form breeds and biological types that can adapt to different environments partitioned ancestral genetic diversity into distinct modern lineages. Genome-wide selection particularly for adaptation to extreme environments left detectable signatures genome-wide. We used high-density genotype data for 42 cattle breeds and identified the influence of Bos grunniens and Bos javanicus on the formation of Chinese indicine breeds that led to their divergence from India-origin zebu. We also found evidence for introgression, admixture, and migration in most of the Chinese breeds. Selection signature analyses between high-altitude (≥1800 m) and low-altitude adapted breeds (<1500 m) revealed candidate genes (ACSS2, ALDOC, EPAS1, EGLN1, NUCB2) and pathways that are putatively involved in hypoxia adaptation. Immunohistochemical, real-time PCR and CRISPR/cas9 ACSS2-knockout analyses suggest that the up-regulation of ACSS2 expression in the liver promotes the metabolic adaptation of cells to hypoxia via the hypoxia-inducible factor pathway. High altitude adaptation involved the introgression of alleles from high-altitude adapted yaks into Chinese Bos taurus taurus prior to their formation into recognized breeds and followed by selection. In addition to selection, adaptation to high altitude environments has been facilitated by admixture and introgression with locally adapted cattle populations.

本研究旨在对荷斯坦牛的牛奶脂肪酸指标表型以及遗传规律进行挖掘,为该性状的选择提供理论基础.本实验收集2019年12月到2020年7月山东及周边地区49个牧场30016头健康荷斯坦牛的53172条测定日记录,包含饱和脂肪酸(Saturated Fatty Acid,SFA)、不饱和脂肪酸(Unsaturated Fatty Acid,UFA)、单不饱和脂肪酸(Monounsaturated Fatty Acid,MUFA)、多不饱和脂肪酸(Polyunsaturated Fatty Acid,PUFA)、棕榈酸C16:0(Palmitic Acid,PA)、硬脂酸C18:0(Stearic Acid,SA)、油酸C18:1 cis-9(Oleic Acid,OA)7种脂肪酸的预测表型信息,利用SAS的GLM过程进行多因素方差分析,探究对脂肪酸含量存在显著影响的环境因素;使用DMU软件估计各脂肪酸的遗传力及其之间的表型相关和遗传相关.结果显示,场年月、泌乳阶段、产犊月份、体细胞评分对各脂肪酸均存在极显著影响(P<0.01),而胎次只对MUFA、OA、PUFA存在显著影响;各脂肪酸估计遗传力在0.04～0.10之间、估计重复力为中低水平(0.16～0.26);各脂肪酸之间均呈正的中高遗传相关(0.32～0.97);各脂肪酸之间表型相关范围为0.44～0.99,和遗传相关方向一致且多数性状间表型相关大于遗传相关.本研究结果显示牛奶脂肪酸比例存在遗传变异,说明荷斯坦牛脂肪酸性状有望通过选择进行遗传改良,获得的遗传参数为牛奶脂肪酸的选择提供了参考.

本文从液态奶产量、生鲜乳行情、饲料价格、乳制品企业发展及奶源基地建设等方面介绍了2019年山东省奶业发展情况,分析了当前山东省奶业面临的问题,并结合山东省奶业发展的实际,提出了促进山东省奶业健康发展的建议.

BACKGROUND:Neutrophils are the first effectors of inflammatory response triggered by mastitis infection, and are important defense cells against pathogenic Escherichia coli (E. coli). DNA methylation, as a critical epigenetic mechanism for regulating gene function, is involved in bovine mastitis.RESULTS:In this study, we sequenced the blood neutrophils of healthy and E. coli-infected mastitic half-sib cows for the overall DNA methylation levels using transcriptome sequencing and reduced representation bisulfite sequencing. The methylation levels in the mastitis cows (MCs) were decreased compared with healthy cows (HCs). A total of 494 differentially methylated regions were identified, among which 61 were up-methylated and 433 were down-methylated (MCs vs. HCs). The expression levels of 1094 differentially expressed genes were up-regulated, and 245 genes were down-regulated. Twenty-nine genes were found in methylation and transcription data, among which seven genes' promoter methylation levels were negatively correlated with expression levels, and 11 genes were differentially methylated in the exon regions. The bisulfite sequencing PCR and quantitative real-time PCR validation results demonstrated that the promoter methylation of CITED2 and SLC40A1 genes affected differential expression. The methylation of LGR4 exon 5 regulated its own alternative splicing. The promoter methylation of bta-miR-15a has an indirect effect on the expression of its target gene CD163. The CITED2, SLC40A1, and LGR4 genes can be used as candidates for E. coli-induced mastitis resistance.CONCLUSIONS:This study explored the roles of DNA methylation in affecting transcription of protein-coding genes and miRNAs in E. coli-induced mastitis, thereby helping explain the function of DNA methylation in the pathogenesis of mastitis and provided new target genes and epigenetic markers for mastitis resistance breeding in dairy cattle.

本文从液态奶产量、饲料价格、乳制品企业发展及奶源基地建设等方面介绍了2018年山东省奶业发展情况,分析了当前山东省奶业面临的问题,并结合山东省奶业发展的实际,提出了促进山东省奶业健康发展的建议.

本文简述了牛场大通铺卧床的含义及国内外应用情况,并通过牛场实例较为详细地介绍了大通铺卧床的建设、管理及使用效果,总结了这种卧床的优点及应用限制条件,为奶牛场从源头减少粪污量提供一种思路.

我国大规模开展奶牛生产性能测定(DHI)工作已有十多年的时间,目前已形成了一套完整的工作流程,包括奶样采集与资料上报、样品检测、仪器校准与保养、质量控制、数据处理、报告分析及应用等内容.奶样采集作为DHI工作的关键环节,其工作好坏影响着DHI技术在牛场应用的效果.山东省农业科学院奶牛研究中心在传统DHI奶样采集方法的基础上,初步研发了一套基于奶牛电子耳标和采样瓶条形码识别的系统,并利用互联网+现代信息技术,提高DHI采样工作效率和准确性,实现了DHI奶样采集的信息化.现将信息化采样系统进行介绍,并就其在DHI中的应用前景进行分析.

Single-nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) and their target binding sites affect miRNA function and are involved in biological processes and diseases, including bovine mastitis, a frequent inflammatory disease. Our previous study has shown that bta-miR-2899 is significantly upregulated in the mammary gland tissue of mastitis-infected cow than that of healthy cows. In the present study, we used a customized miRNAQTLsnp software and identified 5252 SNPs in 691 bovine pre-miRNAs, which are also located within the quantitative trait loci (QTLs) that are associated with mastitis and udder conformation-related traits. Using luciferase assay in the bovine mammary epithelial cells, we confirmed a candidate SNP (rs109462250, g. 42,198,087 G > A) in the seed region of bta-miR-2899 located in the somatic cell score (SCS)-related QTL (Chr.18: 33.9–43.9 Mbp), which affected the interaction of bta-miR-2899 and its putative target Spi-1 proto-oncogene (SPI1), a pivotal regulator in the innate and adaptive immune systems. Quantitative real-time polymerase chain reaction results showed that the relative expression of SPI1 in the mammary gland of AA genotype cows was significantly higher than that of GG genotype cows. The SNP genotypes were associated with SCS in Holstein cows. Altogether, miRNA-related SNPs, which influence the susceptibility to mastitis, are one of the plausible mechanisms underlying mastitis via modulating the interaction of miRNAs and immune-related genes. These miRNA-QTL-SNPs, such as the SNP (rs109462250) of bta-miR-2899 may have implication for the mastitis resistance breeding program in Holstein cattle.

This study compared six models, namely the Gaines, Sikka, Nelder, Wood, Dhanoa and Hayashi models, for the estimation of 305 days milk yield in Chinese Holstein cattle. We compared their ability to reliably predict 305-day lactation yield from incomplete (3 or 6 test-day (TD)) records. Our findings revealed that the accuracies (ACC) were 0.6655-0.9948, 0.8652-0.9977 and 0.9169-0.9968, whereas the mean square errors (MSE) were 0.0121-2.4807, 0.0139-1.0716 and 0.0170-0.5528 when 3 TD records were used in the first, second and higher lactations, respectively; when 6 TD records were used, the ACC were 0.8800-0.9992, 0.8742-0.9998 and 0.7950-0.9996, whereas the MSE values were 0.0017-0.3348, 0.0011- 0.8605 and 0.0021-1.4869 in the first, second and higher lactations, respectively. All the models were fitted more accurately with 6 TD than 3 TD records. Further analysis revealed that the curves made by the Nelder, Wood and Dhanoa models were close to the actual curves. These three models can be used to predict the 305-day yield for management decisions in farms and for the genetic evaluation of Chinese Holstein cattle.

本文介绍了山东省2017年奶业发展情况,分析了当前山东奶业在发展中面临的问题,如环保压力、土地资源约束、乳企限量等,并对这些问题进行剖析,提出了促进山东省奶业健康发展的对策与建议.

本文简述了乳中真蛋白和粗蛋白的定义、关系及测定方法,介绍了凯氏定氮和近红外光谱分析两种常见的乳蛋白测定方法及各自优势.分析了部分DHI参测牛场的乳蛋白测定数据,比较了真蛋白和粗蛋白一年的变化情况,以及在不同牛群测定结果的差异.结合国外计价体系的变化,分析了利用真蛋白计价的优势.

山东省农业科学院DHI测定实验室建成于2006年,现有专业技术人员15人,实验室拥有乳成分分析仪、流量计校准仪、尿素氮标定仪、牛B超妊娠检测仪、挤奶机检测仪等配套仪器设施,技术装备先进,技术力量雄厚.历经12年发展,实验室技术团队励精图治,团结一心,勇于进取,综合能力持续提升,业界影响不断扩大,取得一系列可喜成绩和丰富成果,为加快推动山东省奶业转型升级,促进奶牛养殖提质增效,做出了重要贡献.

喷淋是奶牛场常用的夏季防暑降温措施。本文选择了15个DHI奶牛场，其中8个没有喷淋装置，7个有喷淋装置，对比分析夏季产奶量变化程度。结果表明，正确使用喷淋能有效降低热应激水平，减小产奶量降幅；对于不使用喷淋的牛场，高产牛群的奶量降幅高于低产牛群。

[This corrects the article DOI: 10.1371/journal.pone.0159719.].