Month-Wise Prevalence of Subclinical Mastitis in Dairy Cows in Guangdong Province,China

To evaluate the month-wise prevalence of subclinical mastitis （SM） and its relations with climatic temperature and humidity, and to provide references for control and prevention of mastitis in dairy cows in Guangdong, China, California mastitis test method was used to determine the monthly prevalence of SM （MPSM, %） of lactating Holstein cows from 11 dairy farms in Guangdong Province, China, including about 516 cows per monthly examination. The average MPSM on a cow and a quarter basis were 30 and 13% respectively, and there was a positive linear correlation between monthly mean air temperature （MT, °C） and MPSM on a cow basis （r=0.763, P=0.004） or a quarter basis （r=0.577, P=0.049）, but there were no correlations between MT and MPSM on a cow or a quarter basis （P〉0.05）. There was a shift in MPSM trend that the highest MPSM （38.4%） was not for the hottest July with MT at 30.8°C, but for the later September at 27.9°C. The farms need to develop new housing conditions to control cowshed temperatures in the hot season to reduce the mastitis prevalences in the post-hot months.

Mastitis Pathogens Isolated from Samples of Milk in Dairy Cows and Their Resistance against Antimicrobial Agents

The objective of this study was to evaluate the effectiveness of different antibiotics against mastitis causing microorganisms during first phase of lactation in herd of 320 Holstein cows in east of Slovakia. Milk samples from quarters were cultured and identified bacteria were subjected to antimicrobial susceptibility test by disc diffusion method to a large number of antibiotics. The results revealed higher sensitivity against tetradelta (100% of Strep. Agalactiae and Strep. uberis, Coagulase Negative Staphylococci), (94.4% of Stap. aureus) with highest number of bacterial isolates, followed by cefalexin + kanamycin amoxicillin plus clavulanat acid and ceftiotur (100% of Strep. agalactiae and Strep. uberis). Resistance was observed against penicillin (22.2% of Stap. aureus) amoxicillin (22.2% of Stap. aureus and 10.5% of Strep. uberis) and streptomycin (22.2% of Stap. aureus and 52.7% of Strep. uberis).

Molecular characteristics,antibiogram and prevalence of multi-drug resistant Staphylococcus aureus (MDRSA) isolated from milk obtained from culled dairy cows and from cows with acute clinical mastitis

To study the molecular characteristics, antibiogram and prevalence of multi-drug resistant Staphylococcus aureus (S. aureus) (MDRSA) isolated from milk obtained from culled dairy cows and from cows with acute clinical mastitis.MethodsBacteria were cultured from 188 quarter milk samples obtained from cows before culling (n = 139) and from cows affected with acute mastitis (n = 49) belonging to 10 dairy farms. The bacteria were identified using colony morphology, Gram staining and biochemical characteristics. S. aureus isolates were then subjected to molecular characterization using PCR targeting 16S rRNA and mecA gene to identify Methicillin resistant S. aureus (MRSA). The antibiogram of all isolates was performed using the Kirby-Bauer disk diffusion method against 10 commonly used antibiotics in dairy farms.ResultsS. aureus was isolated from 19 (13.7%) samples obtained from culled cows and 11 (22.4%) samples obtained from cows with acute mastitis. In both culled cows and cows with acute mastitis, in vitro antibiogram revealed that 100% of S. aureus isolates were resistant to erythromycin, penicillin G, streptomycin, doxycyclin, and trimethoprim/sulpha. The prevalence of MRSA in milk of culled cows and cows with acute mastitis was 26.3% and 18.2%, respectively, with an overall prevalence of 3.7% among all samples. All MRSA isolates were completely resistant to all tested antibiotics. All MRSA isolates were positive for the presence of the mecA gene.ConclusionsMRSA carrying the mecA gene were isolated from mastitic milk from dairy cows in Jordan for the first time. MRSA may pose a potential health risk to the public, farm workers and veterinarians.

Multiple PCR for Detection of Subclinical Mastitis in Dairy Cow

[ Objective] To develop a rapid, sensitive, specific and accurate diagnostic method for subclinical mastitis in dairy cow. [ Method] A total of 70 samples of suspected clinical mastitis cows were detected in gene level by multiple PCR. [Result] The 58 samples were positive with the developed multiple PCR method and the positive rate was 82.5% （58/70）. The 53 samples were positive with the traditional biochemical method and the positive rate was 75.5% （53/70）. As a result, the coincidence rate of both methods was 92%. [ Conclusion] The multiple PCR method is rapid and specific for the detection of pathogenic subclinical mastitis in dairy cow.

Effects of Xiaoruling on Subclinical Mastitis in Dairy Cows

[Objective] TO investigate the effects of traditional Chinese medicine （TCM） preparation ＂Xiaoruling＂ on the subclinical mastitis in dairy cows. [Method] A total of 28 dairy cows suffering from subclinical mastitis were randomly divided into experimental group （n =20） and control group （ n =8）. The dairy cows in the experimental group were treated with Xiaoruling for 2 weeks. [ Rsults] The cure rate of subclinical mastitis in dairy cows was up to 89.47% and milk yield increased greatly （ P 〈 0.05）. Meanwhile, the milk somatic cell count （SCC） was greatly decreased （ P 〈 0.01 ）. SOD and GSH-Px activities in plasma were increased greatly （ P 〈 0.01 ）. [ Conclusion] Xiaoruling has an effective treatment on subclinical mastitis in dairy cows.

Rumen microbiome structure and metabolites activity in dairy cows with clinical and subclinical mastitis

Background:Due to the high prevalence and complex etiology,bovine mastitis(BM)is one of the most important diseases to compromise dairy cow health and milk quality.The shift in milk compositions has been widely investigated during mastitis,but recent studies suggested that gastrointestinal microorganism also has a crucial effect on the inflammation of other peripheral tissues and organs,including the mammary gland.However,research focused on the variation of rumen inner-environment during mastitis is still limited.Therefore,the ruminal microbial profiles,metabolites,and milk compositions in cows with different udder health conditions were compared in the present study.Furthermore,the correlations between udder health status and ruminal conditions were investigated.Based on the somatic cell counts(SCC),California mastitis test(CMT)parameters and clinical symptoms of mastitis,60 lactating Holstein dairy cows with similar body conditions(excepted for the udder health condition)were randomly divided into 3 groups(n=20 per group)including the healthy(H)group,the subclinical mastitis(SM)group and the clinical mastitis(CM)group.Lactation performance and rumen fermentation parameters were recorded.And rumen microbiota and metabolites were also analyzed via 16S rRNA amplicon sequencing and untargeted metabolomics,respectively.Results:As the degree of mastitis increased,rumen lactic acid(LA)(P<0.01),acetate,propionate,butyrate,valerate(P<0.001),and total volatile fatty acids(TVFAs)(P<0.01)concentrations were significantly decreased.In the rumen of CM cows,the significantly increased bacteria related to intestinal and oral inflammation,such as Lachnospiraceae(FDR-adjusted P=0.039),Moraxella(FDR-adjusted P=0.011)and Neisseriaceae(FDR-adjusted P=0.036),etc.,were accompanied by a significant increase in 12-oxo-20-dihydroxy-leukotriene B4(FDR-adjusted P=5.97×10^(−9))and 10beta-hydroxy-6beta-isobutyrylfuranoeremophilane(FDR-adjusted P=3.88×10^(−10)).Meanwhile,in the rumen of SM cows,the Ruminiclostridium_9(FDR-adjusted P=0.042)and Enterorhabdus(FDR-adjusted P=0.043)were increased along with increasing methenamine(FDR-adjusted P=6.95×10^(−6)),5-hydroxymethyl-2-furancarboxaldehyde(5-HMF)(FDR-adjusted P=2.02×10^(−6))and 6-methoxymellein(FDR-adjusted P=2.57×10^(−5)).The short-chain fatty acids(SCFAs)-producing bacteria and probiotics in rumen,including Prevoterotoella_1(FDRadjusted P=0.045)and Bifidobacterium(FDR-adjusted P=0.035),etc.,were significantly reduced,with decreasing 2-phenylbutyric acid(2-PBA)(FDR-adjusted P=4.37×10^(−6)).Conclusion:The results indicated that there was a significant shift in the ruminal microflora and metabolites associated with inflammation and immune responses during CM.Moreover,in the rumen of cows affected by SM,the relative abundance of several opportunistic pathogens and the level of metabolites which could produce antibacterial compounds or had a competitive inhibitory effect were all increased.

Feeding a Saccharomyces cerevisiae fermentation product improves udder health and immune response to a Streptococcus uberis mastitis challenge in mid-lactation dairy cows

Background:We aimed to characterize the protective effects and the molecular mechanisms of action of a Saccharomyces cerevisiae fermentation product(NTK)in response to a mastitis challenge.Eighteen mid-lactation multiparous Holstein cows(n=9/group)were fed the control diet(CON)or CON supplemented with 19 g/d NTK for 45 d(phase 1,P1)and then infected in the right rear quarter with 2500 CFU of Streptococcus uberis(phase 2,P2).After 36-h,mammary gland and liver biopsies were collected and antibiotic treatment started until the end of P2(9 d post challenge).Cows were then followed until day 75(phase 3,P3).Milk yield(MY)and dry matter intake(DMI)were recorded daily.Milk samples for somatic cell score were collected,and rectal and udder temperature,heart and respiration rate were recorded during the challenge period(P2)together with blood samples for metabolite and immune function analyses.Data were analyzed by phase using the PROC MIXED procedure in SAS.Biopsies were used for transcriptomic analysis via RNA-sequencing,followed by pathway analysis.Results:DMI and MY were not affected by diet in P1,but an interaction with time was recorded in P2 indicating a better recovery from the challenge in NTK compared with CON.NTK reduced rectal temperature,somatic cell score,and temperature of the infected quarter during the challenge.Transcriptome data supported these findings,as NTK supplementation upregulated mammary genes related to immune cell antibacterial function(e.g.,CATHL4,NOS2),epithelial tissue protection(e.g.IL17C),and anti-inflammatory activity(e.g.,ATF3,BAG3,IER3,G-CSF,GRO1,ZFAND2A).Pathway analysis indicated upregulation of tumor necrosis factorα,heat shock protein response,and p21 related pathways in the response to mastitis in NTK cows.Other pathways for detoxification and cytoprotection functions along with the tight junction pathway were also upregulated in NTK-fed cows.Conclusions:Overall,results highlighted molecular networks involved in the protective effect of NTK prophylactic supplementation on udder health during a subclinical mastitic event.

Identification of novel molecular markers of mastitis caused by Staphylococcus aureus using gene expression profiling in two consecutive generations of Chinese Holstein dairy cattle

Background: Mastitis in dairy cows caused by Staphylococcus aureus is a major problem hindering economic growth in dairy farms worldwide. It is difficult to prevent or eliminate due to its asymptomatic nature and long persistence of infection. Although transcriptomic responses of bovine mammary gland cells to pathogens that cause mastitis have been studied, the common responses of peripheral blood leukocytes to S. aureus infection across two consecutive generations of dairy cattle have not been investigated.Methods: In the current study, RNA-Seq was used to profile the transcriptomes of peripheral blood leukocytes sampled from S. aureus-infected mothers and their S. aureus-infected daughters, and also healthy non-infected mothers and their healthy daughters. Differential gene expression was evaluated as follows: 1) S. aureus-infected cows versus healthy non-infected cows(S vs. H, which include all the mothers and daughters), 2) S. aureus-infected mothers versus healthy non-infected mothers(SM vs. HM), and 3) S. aureus-infected daughters versus healthy noninfected daughters(SMD vs. HMD).Results: Analysis of all identified expressed genes in the four groups(SM, SMD, HM, and HMD) showed that EPOR,IL9, IFNL3, CCL26, IL26 were exclusively expressed in both the HM and HMD groups, and that they were significantly(P < 0.05) enriched for the cytokine-cytokine receptor interaction pathway. A total of 17, 13 and 10 differentially expressed genes(DEGs)(FDR Padj. < 0.1 and |FC| > 1.2) were detected in the three comparisons, respectively. DEGs with P < 0.05 and |FC| > 2 were used for functional enrichment analyses. For the S vs. H comparison, DEGs detected included CCL20, IL13 and MMP3, which are associated with the IL-17 signaling pathway. In the SM vs. HM and SMD vs. HMD comparisons, five(BLA-DQB, C1 R, C2, FCGR1 A, and KRT10) and six(BLA-DQB, C3 AR1, CFI, FCAR, FCGR3 A, and LOC10498484) genes, respectively, were involved in the S. aureus infection pathway.Conclusions: Our study provides insights into the transcriptomic responses of bovine peripheral blood leukocytes across two generations of cattle naturally infected with S. aureus. The genes highlighted in this study could serve as expression biomarkers for mastitis and may also contain sequence variation that can be used for genetic improvement of dairy cattle for resilience to mastitis.

Development of a PCR Diagnostic Kit for Cryptosporidium andersoni in Dairy Cow

Cryptosporidiosis is an important zoonosis caused by the Cryptosporidium species. To develop a PCR diagnostic kit for molecular detection and differential diagnosis of Cryptosporidium spp., a portion of ITS-1 sequence of Cryptosporidium. andersoni was chosen as the target DNA for designing the species-specific primers （ZRQF/ZR）. The kit components were determined after the PCR amplification conditions were serially optimized. A series of tests were conducted in the specificity, sensitivity, stability, reproducibility, and stored period of the kit, respectively. The results showed that only C. andersoni were amplified specific band of about 500 bp, while Cryptosporidium. parvum, Cryptosporidium. baileyi, Eimeria sp of dairy cow, Toxoplasma gondii, Eimeria sp of pig, Ascaris suum, Cyclospora sp, and E. coli could not be amplified. 254 oocysts of C. andersoni was the lowest number that could be detected using the kit. The kit worked well after being stored at room temperature, 4 and -20℃ for nine months. Fecal specimens, which were collected from a total of 243 calves on four different dairy farms in Guangdong Province, China, and one dairy farm in Henan Province, China, were examined using the kit; the positive rate of the kit was 2-13% higher than that of the routine methods. The results indicated that the kit can detect fecal samples faster, more sensitively, and conveniently, and can provide a useful tool for the identification and differentiation of C. andersoni from the other Cryptosporidium species; it also has implications for further studies on molecular epidemiology and differential diagnostics of cryptosporidiosis in animals.

Comparative Proteomic Analysis of Plasma from Clinical Healthy Cows and Mastitic Cows

The current research presents the protein changes in plasma from healthy dairy cows and clinical mastitic cows using two- dimensional gel electrophoresis （2-DE）. After staining with silver nitrate and Coomassie Blue, differential expression proteins were detected by PDQuest 7.4 software, and then subjected to ion trap mass spectrometer equipped with a Surveyor HPLC System, differential spots of protein were identified. Three protein spots that originated from preparation gels were identified to be two proteins. Overall, haptoglobin precursor was up-regulated in cows infected with clinical mastitis and could be a mastitis-associated diagnostic marker, whereas SCGB 2A1 （secretoglobin, family 2A, member 1） was down-regulated protein. Plasma protein expression patterns were changed when cows were infected with mammary gland inflammation; it suggests that analysis of differential expression protein might be useful to clarify the mechanisms involved in the pathophysiology, and find new diagnostic markers of mastitis and potential protein targets for treatment.

Experimental Intramammary Infection with a Strain of <i>Escherichia coli</i>Isolated from a Cow with Persistent <i>E. coli</i>Mastitis

Transient E. coli intramammary infections (IMI) are usually associated with rapid onset of clinical signs including mammary gland swelling and abnormal milk with rapid clearance of bacteria from milk. Conversely, reports have described strains of E. coli showing very different clinical trends. Persistent E. coli IMI are associated with mild clinical symptoms that disappear shortly after the onset of infection, possibly flaring-up intermittently during lactation. In the present study, we evaluated a strain of E. coli isolated from a cow with persistent mastitis to determine if the experimental infection model mimics naturally occurring persistent E. coli IMI. Uninfected mammary quarters of 7 Holstein heifers were infused within 10 days of calving with 50 colony-forming units of a persistent E. coli strain. Six of 7 heifers developed mild clinical mastitis with elevated rectal temperatures within 9 to 36 h after infusion. The challenge strain was isolated intermittently in milk from all infected mammary quarters during the first two weeks after infusion and 3 animals continued to shed E. coli periodically during the sampling period. One animal shed E. coli intermittently in milk for 172 d after challenge and developed clinical mastitis four times during this period. The isolated strain had an identical pulsed-field gel electrophoresis profile as the E. coli strain used to infuse mammary glands. The experimental IMI model described here mimics very closely naturally occurring persistent E. coli IMI, thus providing an excellent in vivo model to better understand pathogenesis and to facilitate development of control strategies for this important mastitis pathogen.

Differences in severity of mastitis and the pathogens causing various oxidative product levels

Differences in severity of mastitis and their causing pathogens might be associated with oxidative product levels occurring during the inflammatory process in infected udders. The objectives of this study were to determine the relationship of oxidative product levels, using malondialdehyde (MDA) as a marker on both mastitis severity and its causing pathogens. Quarter milk samples of all lactating cows in the selected farms were primarily tested for mastitis severity levels including clinical and subclinical mastitis. All quarter milk samples from mastitis cows were separately collected for MDA measurement and bacteriological analyses. Results showed that MDA in clinical mastitis quarters was highest in comparison to sub-clinical mastitis and healthy quarters. MDA in milk samples with Strep. uberis and coagulase negative staphylococci was higher than in milk samples without any pathogens (p < 0.05). In conclusion, differences in both severity of mastitis and mastitis pathogens were associated with differences of oxidative products in infected udders.

Isolation and Identification of Pathogenic Bacteria Causing Bovine Subclinical Mastitis in Eastern Hebei Province

In this study, the milk samples of 1 021 cows in eight dairy farms in Eastern Hebei Province were collected and detected with LMT reagent and somatic cell count for subclinical mastitis. Pathogenic bacteria in subclinical mastitis positive milk samples were isolated and identified.The results showed that 60.63%（619/1 021） of the sampled cows were diagnosed with subclinical mastitis, and mixed infections accounted for 88.21%（546/619） of the cases. In addition, 82 strains of 14 species were isolated from the subclinical mastitis positive milk samples, including 36 strains of Staphylococcus（43.90%）, 33 strains of Streptococcus（40.24%）, 8 strains of Enterobacteriaceae（9.76%） and 5 strains of Corynebacterium（6.10%）, respectively. The results proved that Staphylococcus aureus and Streptococcus agalactiae are the main pathogenic bacteria causing bovine subclinical mastitis in Eastern Hebei Province.

国外奶牛乳房炎研究进展——基于Web of Science核心数据库

随着人类社会工业化现代化进程的加快和经济的高速发展,人类对牛奶的需求量逐渐加大,高产奶牛的选育和替代人工的挤奶设备应用开始进入发展的快车道,与此同时也带来了奶牛乳房炎的“爆发式”增长,成为了当代奶牛养殖业的三大最主要疾病之一。国内外的专家学者也在不断地寻求有效方法,以最大限度地减少奶牛乳房炎的发生。国外在乳房炎方面的研究走在了国内的前面,他们的先进技术理念、手段和方法非常值得国内的借鉴。本文基于web of science核心数据库,用CiteSpace软件对近3年乳房炎相关的文献进行检索,并将其中经典文献进行总结归纳,以展示国外最新的乳房炎研究进展。

Association between Single Nucleotide Polymorphism in RelA with Somatic Cell Count and Longevity Supports Importance of NF-κB Signalling in Cattle Health

Mastitis reduces milk production and causes culling. The NF-κB transcription factor RelA plays a central regulatory role in innate immunity. This study used a candidate gene approach to investigate associations between the synonymous C/G SNP rs48035703 in RELA with somatic cell count (SCC) and survival time. Blood samples were collected from 337 Holstein-Friesian heifers on 19 farms and genotyped by PCR-restriction fragment length polymorphism. Animals were monitored from 6 months until 2340 d of age. Pedigree, milk production and disease records were obtained. Genotype frequencies were CC 0.63, CG 0.30 and GG 0.06. The C allele had a favourable additive effect on survival: average longevities from birth were CC, 1872 d;CG, 1745 d and GG 1596 d (P < 0.003). Log transformed first lactation somatic cell count (SCC)data showed a significant association with this SNP using an allele substitution model (mean residuals ± SD: GG 0.30 ± 1.263;CG 0.22 ± 0.994, CC -0.04 ± 0.803, P < 0.05). More CC cows than expected were classified as intermediate and fewer as mastitic (30.4% v 45.9%) with respect to SCC class when categorised as 0 (unaffected), 1 (intermediate) and 2 (mastitic), whereas for CG heterozygotes fewer were intermediate and more were mastitic (12.1% v 60.3%) (p = 0.05). RELA rs48035703 CC genotype cows were therefore less likely to experience a high SCC and survived longer. These results support a role for RelA in combating mammary gland infection and warrant further studies in additional populations.

Automatic lameness detection in dairy cows based on machine vision

This study proposed a method for detecting lameness in dairy cows based on machine vision,addressing the challenges associated with manual detection.Data from a dairy farm in Taigu,Shanxi,China were collected and divided into two parts.The first part was utilized to precisely position the cow’s back by employing a dedicated deep learning model named GhostNet_YOLOv4,which can be implemented on mobile or embedded devices.The second part was used with the Visual Background Extractor(Vibe)algorithm,incorporating additional morphological processing techniques.Enhancing the Vibe algorithm,a widely used background subtraction algorithm for image sequences,achieved more accurate recognition of the specific pixel areas of cows.Subsequently,cow shape-related feature parameters were extracted from the back area using the combined approach.These parameters were used to calculate the average curvature,which describes the degree of curvature of the cow’s back contour during walking.The differences in curvature values were employed for classification to detect lameness.Through extensive experimentation,distinct average curvature ranges of[−0.025,−0.125],[−0.025,+∞],and[−∞,−0.125]were established for normal cows,early lameness,and moderate-severe lameness,respectively.The algorithm’s effectiveness was validated by processing 600 image sequences of dairy cows,resulting in a lameness detection accuracy of 91.67%.These findings can serve as a reference for the timely and accurate recognition of lameness in dairy cows.

湖南某规模奶牛场乳房炎病原菌的分离鉴定与耐药性分析

为明确湖南某规模奶牛场临床型乳房炎病原菌种类及耐药情况,对32份临床型乳房炎患牛乳样进行传统细菌培养、生化试验、16S rDNA核苷酸序列检测和药敏试验。结果共分离鉴定大肠杆菌23株,乳房链球菌12株,肺炎克雷伯氏菌5株,样品检出率分别为71.9%(23/32)、37.5%(12/32)、15.6%(5/32);药敏试验显示,大部分大肠杆菌和乳房链球菌对青霉素、阿莫西林、头孢他啶、庆大霉素、林可霉素耐药严重,耐药率达50%~86.9%,对亚胺培南、四环素及红霉素较敏感,敏感率达75%~82.6%;肺炎克雷伯氏菌对大部分抗生素耐药程度较低,对亚胺培南、阿米卡星、四环素、红霉素敏感率为100%。建议该养殖场抓好环境卫生、提高生物安全,建立科学、合理治疗方案。

基于网络药理学探究金银花-连翘治疗奶牛乳房炎的作用机制及体外验证

为了探究金银花-连翘治疗奶牛乳房炎的作用机制,试验采用中药系统药理学分析(TCMSP)数据库获得金银花-连翘的活性成分及相关作用靶点蛋白,并将作用靶点蛋白进一步转化为靶点基因;利用DisGeNET数据库、GeneCards数据库和NCBI数据库检索奶牛乳房炎相关基因靶点;通过String数据库和Cystoscape v3.7.1软件构建金银花-连翘的有效活性成分靶点与奶牛乳房炎疾病靶点蛋白互作(PPI)网络图;采用David数据库进行金银花-连翘与奶牛乳房炎交集靶点所涉及的GO功能注释与KEGG信号通路富集分析,进而探究金银花-连翘治疗奶牛乳房炎的作用机制;建立奶牛乳腺上皮细胞炎症模型,采用ELISA检测金银花-连翘水提物对相关细胞因子表达的影响。结果表明:金银花-连翘主要活性成分包括β-谷甾醇、山奈酚、木犀草素、槲皮素等;共筛选获得239个药物活性成分主要涉及基因靶点及296个奶牛乳房炎基因靶点,其中交集靶点38个,以肿瘤坏死因子(TNF)、白细胞介素-6(IL-6)、白蛋白(ALB)、白细胞介素-1β(IL-1β)、白细胞介素-8(CXCL8)等为主。GO功能注释到的生物进程主要包括MAP激酶活性的正调控、炎症反应、一氧化氮生物合成过程的正调控等;细胞组分主要包括细胞核、细胞质、细胞表面等;分子功能主要包括细胞因子活性、转录因子活性等。KEGG信号通路主要富集在脂质与动脉粥样硬化、IL-17信号通路等;金银花-连翘水提物在体外可显著降低IL-6、IL-1β和CXCL8水平(P<0.05),发挥抗炎作用。说明金银花-连翘可能通过β-谷甾醇、山奈酚、木犀草素、槲皮素等活性成分调节IL-17信号通路,并作用于IL-6、IL-1β、CXCL8等靶点来治疗奶牛乳房炎。

Potential of an activity index combining acceleration and location for automated estrus detection in dairy cows

The objective of this study was to assess the effectiveness and practicability of an activityindex combining acceleration and location data for automated estrus detection in dairycows. By using a wearable neck tag, measurements of acceleration and location were gathered from 22 multiparous cows monitored incessantly for 6 days to derive activity recordsof each cow. The maximum-minimum distance clustering (MMDC) method was used todivide hourly activity data into low, medium, high, and intensity level groups. The weightedsum of the proportions of the low, medium, high, and intensity activities in an hour constituted the activity level. The activity index was defined as the ratio of the variation inhourly activity level compared to the same time period during the previous three days. Furthermore, whether the cow was in estrus was judged above a set threshold. The studyshowed that the power consumption and communication effects of the neck tags wereacceptable for indoor-housing conditions. For the two consecutive time periods, theactivity-index-based detection algorithm achieved 90.91% for accuracy, 100% for precision,100% for specificity, 83.33% for recall, 90.91% for F1 score, and 0.82 for Kappa coefficient. Onthe basis of these results, it can be concluded that the combination of acceleration andlocation in the activity index can promote estrus detection in dairy cows.

奶牛乳房炎金黄色葡萄球菌免疫逃避机制研究进展

奶牛乳房炎是奶牛养殖业最常见的疾病之一,严重影响奶牛泌乳量和奶品质,增加奶牛淘汰率。饲养条件、环境因素及病原菌等都可诱发奶牛乳房炎,其中金黄色葡萄球菌(Staphylococcus aureus)导致的奶牛乳房炎最难治愈。金黄色葡萄球菌是一种具有高致病性、高耐药性且能通过自身分泌的酶、毒力因子介导免疫逃避作用的致病菌,其在宿主体内长期存活可导致长期慢性奶牛乳房炎的发生。笔者首先从奶牛乳腺免疫防御方面揭示奶牛乳腺在金黄色葡萄球菌入侵时所产生的一系列免疫防御手段;其次从金黄色葡萄球菌依靠自身表达的毒力因子、生物膜、表面蛋白及进化过程中产生小菌落变种、持留菌等不断增强其致病性和高耐药性方面进行阐述,揭示金黄色葡萄球菌高致病性和高耐药性的原因,以及金黄色葡萄球菌导致的奶牛乳房炎难以治愈的原因;最后进一步阐明金黄色葡萄球菌是如何在宿主强大的免疫防御作用下存活,以及通过荚膜多糖和纤维连接蛋白在乳腺定植并逃避吞噬,分泌中性粒细胞丝氨酸蛋白酶抑制蛋白、葡萄球菌蛋白A、产生细胞外囊泡等毒力因子逃避机体的免疫吞噬作用,揭示金黄色葡萄球菌具有高度环境适应力及众多免疫逃避手段。笔者从以上三方面对金黄色葡萄球菌逃避乳腺天然免疫的机制及相关研究进行综述,为维护奶牛健康、预防奶牛乳房炎疾病发生、抵御病原入侵机体等方面的机制研究提供依据。