The growth-stimulating factor of Treponema phagedenis from bovine digital dermatitis lesions.

Bovine digital dermatitis (BDD) is an infectious skin disease of the hoof characterized by painful ulcerations that cause lameness in dairy cattle. Cell-free supernatants (CFS) of Falsiporphyromonas endometrii predominantly isolated from BDD lesions had the highest growth-stimulating effect on Treponema phagedenis among BDD-associated bacteria. Butyric acid was detected at a concentration of 45.4 mM in CFS of F. endometrii, and the growth of T. phagedenis was significantly promoted by butyric acid supplementation.

The roles of Braun Lipoprotein in inducing tolerance of bovine endometrium infected by Escherichia coli.

Escherichia coli (E. coli), a Gram-negative bacterium, is the primary pathogen responsible for endometritis in dairy cattle. The outer membrane components of E. coli, namely lipopolysaccharide (LPS) and bacterial lipoprotein, have the capacity to trigger the host's innate immune response through pattern recognition receptors (PRRs). Tolerance to bacterial cell wall components, including LPS, may play a crucial role as an essential regulatory mechanism during bacterial infection. However, the precise role of Braun lipoprotein (BLP) tolerance in E. coli-induced endometritis in dairy cattle remains unclear. In this study, we aimed to investigate the impact of BLP on the regulation of E. coli infection-induced endometritis in dairy cattle. The presence of BLP was found to diminish the expression and release of proinflammatory cytokines (IL-8 and IL-6), while concurrently promoting the expression and release of the anti-inflammatory cytokine IL-10 in endometrial epithelial cells (EECs). Furthermore, BLP demonstrated the ability to impede the activation of MAPK (ERK and p38) and NF-κB (p65) signaling pathways, while simultaneously enhancing signaling through the STAT3 pathway in EECs. Notably, BLP exhibited a dual role, acting both as an activator of TLR2 and as a regulator of TLR2 activation in LPS- and E. coli-treated EECs. In E. coli-infected endometrial explants, the presence of BLP was noted to decrease the release of proinflammatory cytokines and the expression of HMGB1, while simultaneously enhancing the release of anti-inflammatory cytokines. Collectively, our findings provide evidence that the bacterial component BLP plays a protective role in E. coli-induced endometritis in dairy cattle.

Bovine Digital Dermatitis: Treponema spp. on trimming equipment and chutes - effect of washing and disinfection.

BACKGROUND: Digital dermatitis (DD) is a contagious bovine foot disease causing reduced animal welfare and negative economic consequences for the farmer. Treponema spp. are the most important causative agents. Studies indicate that trimming equipment can transfer DD-associated treponemes between cows. The aim of this observational study in 22 DD-positive Norwegian dairy herds was to investigate the risk of transferring Treponema spp. with trimming equipment and chutes after claw trimming, and after washing and disinfection. Swabs from the trimming equipment and chutes were collected from nine different locations, at five different time points. Bacterial DNA was extracted from 647 swabs and analysed by qPCR for Treponema spp. In addition, 172 swabs taken immediately after trimming, were analysed by a multiplex qPCR targeting T. phagedenis, T. pedis and T. medium/vincentii. Biopsy sampling from DD lesions was performed on cows in the same herds during trimming. Altogether 109 biopsies were analysed by FISH for confirmation of the DD diagnosis and identification of Treponema phylotypes (PTs). RESULTS: High numbers of Treponema spp. were detected from all nine locations on the trimming equipment and chutes immediately after trimming, and T. phagedenis was detected on two or more locations in all but two herds, 1 and 19. There was a decline in the amount of Treponema spp. after washing and disinfection. The belly belt, the cuff, and the footrest on the chute had the highest proportion of positive samples after disinfection. The belly belt had the highest copy numbers of all nine locations (median = 7.9, max = 545.1). No Treponema spp. was detected on the hoof knives after disinfection. Treponema phagedenis, T. pedis, and Treponema phylotype 3 (T. refringens) were detected by FISH analysis of the biopsies. Treponema phagedenis was detected in biopsies from all herds except 1 and 19. CONCLUSION: This study shows that DD-associated Treponema spp. were present on the trimming equipment and chutes after trimming cows in DD-positive herds. Washing and disinfection reduced the load of Treponema spp. However, large differences in Treponema spp. between different locations were documented. High copy numbers on the grinder and the chute after disinfection, indicates that sufficient cleaning and disinfection of these locations is difficult, and that passive transfer of DD-associated treponemes (viable or not) is possible.

Evaluating the impact of application of anaerobic bacterial fermentation enhancer on digital dermatitis.

The control of digital dermatitis (DD) among cattle is crucial; however, effective and environmentally-sound control measures have yet to be identified. From the monitoring data of DD which were recorded during regular hoof trimmings in a farm in Hokkaido, Japan, we detected a decrease in the DD prevalence in a herd where an anaerobic bacterial fermentation enhancer (ABFE) was distributed. The possible effect of ABFE was analyzed using a retrospective repeated cross-sectional design. The prevalence of DD decreased over time in the ABFE-distributed group. Furthermore, a selected regression model indicated the time-dependent enhancement of the decreasing trend. While potential coincidental factors may influence, this study provides a basis for further research on the preventive effect of ABFE against DD.

A survey of foot disinfection practices for control of bovine digital dermatitis: Evaluating solution depth, footbath hygiene, and the potential of footbaths as infection reservoirs for Treponema species.

Bovine digital dermatitis remains a widespread endemic disease of dairy cattle worldwide. Footbathing is commonly used as a control measure and has significant economic and environmental impacts. Few studies document footbathing practices on dairy farms or evaluate their suitability for achieving foot disinfection. This study describes footbathing practices on 32 farms observed in the United Kingdom, Ireland, and the Netherlands. We measured solution depth throughout footbathing and observed levels below 7 cm on 9 out of 32 farms, which leads to inadequate foot coverage. Solution depth was associated with the number of cow passages and decreased by 1.2 cm for every 100 cow passages. We also describe levels of OM content (g/L) throughout footbathing as a proxy for footbath hygiene. Our data indicates that almost half of footbaths (15/32) became contaminated above the 20 g/L threshold to which veterinary biocides are tested for efficacy, and that OM content is associated with the number of cow passages per liter of footbathing solution provided. A multivariable mixed model predicted that 1 L of footbathing solution per cow should be sufficient to prevent excess contamination. As a further measure of hygiene, we tested a subset of footbath samples to quantify the amount of DNA present from the Treponema species which are considered instrumental in the etiology of digital dermatitis. We did not detect Treponema DNA in footbath samples, which suggested they are unlikely to act as infection reservoirs for this disease. Multivariable mixed models including farm identity as a random effect demonstrated that for both change in solution depth and OM content the effect of farm-level factors was large. Because of the magnitude of this farm effect, applying model predictions will not translate to adequate solution depth and hygiene on all farms. Our data highlights the importance of footbath auditing on individual farms.

Adherence and metal-ion acquisition gene expression increases during infection with Treponema phagedenis strains from bovine digital dermatitis.

Digital dermatitis (DD) is an ulcerative foot lesion on the heel bulbs of dairy cattle. DD is a polymicrobial disease with no precise etiology, although Treponema spirochetes are found disproportionally abundant in diseased tissue. Within Treponema, several different species are found in DD; however, the species Treponema phagedenis is uniformly found in copious quantities and deep within the skin layers of the active, ulcerative stages of disease. The pathogenic mechanisms these bacteria use to persist in the skin and the precise role they play in the pathology of DD are widely unknown. To explore the pathogenesis and virulence of Treponema phagedenis, newly isolated strains of this species were investigated in a subcutaneous murine abscess model. In the first trial, a dosage study was conducted to compare the pathogenicity of different strains across three different treponemes per inoculum (TPI) doses based on abscess volumes. In the second trial, the expression levels of 11 putative virulence genes were obtained to gain insight into their involvement in pathogenesis. During the RT-qPCR analysis, it was determined that genes encoding for two metal-ion import lipoproteins and two adherence genes were found highly upregulated during infection. Conversely, two genes involved in motility and chemotaxis were found to not be significantly upregulated or utilized during infection. These results were supported by gene expression data from natural M2 lesions of dairy cattle. This gene expression analysis could highlight the preference in strategy for T. phagedenis to persist and adhere in the host rather than engage in motility and disseminate.

Metritis and the uterine disease microbiome are associated with long-term changes in the endometrium of dairy cows†.

Cows with metritis (uterine disease) during the first 1 to 2 weeks postpartum have lower pregnancy rates when inseminated later postpartum (typically >10 weeks). We hypothesized that metritis and the disease-associated uterine microbiome have a long-term effect on endometrial gene expression. Changes in gene expression may inform a mechanism through which disease lowers pregnancy rates. A total of 20 cows were enrolled at 1 to 2 weeks postpartum to either metritis (clinical disease; n = 10) or healthy (control; n = 10) groups and randomly assigned to be slaughtered at approximately 80 and 165 dpp (mid-lactation). The microbiome of the reproductive tract was sampled to confirm the presence of pathogens that are typical of metritis. In addition to the original clinical diagnosis, study cows were retrospectively assigned to uterine-disease and control groups based on the composition of their microbiome. There was no effect of early postpartum uterine disease on the uterine microbiome at mid-lactation (time of slaughter). Nonetheless, early postpartum metritis and the disease microbiome were associated with a large number of differentially-expressed genes at mid-lactation primarily in the caruncular compared with the inter-caruncular endometrium. Gene enrichment analysis identified oxidative phosphorylation as the primary pathway increased in caruncular endometrium of diseased cows whereas growth factor signaling pathways were reduced. The current study demonstrated that metritis and a uterine disease microbiome leave a sustained imprint on gene expression in the caruncular endometrium that may explain lower fertility in cows with postpartum uterine disease.

Digital dermatitis in Swedish dairy herds assessed by ELISA targeting Treponema phagedenis in bulk tank milk.

BACKGROUND: Digital dermatitis (DD) is a contagious hoof infection affecting cattle worldwide. The disease causes lameness and a reduction in animal welfare, which ultimately leads to major decreases in milk production in dairy cattle. The disease is most likely of polymicrobial origin with Treponema phagedenis and other Treponema spp. playing a key role; however, the etiology is not fully understood. Diagnosis of the disease is based on visual assessment of the feet by trained hoof-trimmers and veterinarians, as a more reliable diagnostic method is lacking. The aim of this study was to evaluate the use of an enzyme-linked immunosorbent assay (ELISA) on bulk tank milk samples testing for the presence of T. phagedenis antibodies as a proxy to assess herd prevalence of DD in Swedish dairy cattle herds. RESULTS: Bulk tank milk samples were collected in 2013 from 612 dairy herds spread across Sweden. A nationwide DD apparent prevalence of 11.9% (8.1-14.4% CI95%) was found, with the highest proportion of test-positive herds in the South Swedish regions (31.3%; 19.9-42.4% CI95%). CONCLUSIONS: This study reveals an underestimation of DD prevalence based on test results compared to hoof trimming data, highlighting the critical need for a reliable and accurate diagnostic method. Such a method is essential for disease monitoring and the development of effective control strategies. The novelty of ELISA-based diagnostic methods for DD, coupled with the disease's polymicrobial origin, suggests an avenue for improvement. Developing an expanded ELISA, incorporating antigens from various bacterial species implicated in the disease, could enhance diagnostic accuracy. The significance of this study is underscored by the extensive analysis of a substantial sample size (612). Notably, this investigation stands as the largest assessment to date, evaluating the application of ELISA on bulk tank milk for DD diagnosis at the herd level.

Comparison of two serological diagnosis tests for bovine paratuberculosis.

Mycobacterium avium subsp. paratuberculosis (MAP) is the causal agent of paratuberculosis (PTBC), a chronic infectious granulomatous enteritis of ruminants. The PTBC diagnosis with commercial ELISA has limitations in sensitivity and specificity, and its results depend on the state of progress of the disease. This research aimed to evaluate two different ELISAs: (a) an "in-house" ELISA with a sonicated antigen obtained from a MAP I47 strain, and (b) a commercial ELISA. In total, the evaluated sample consisted of 394 bovine serum samples from 12 farms in Argentina with high (5-9%) and low (≤ 0.05%) prevalence of PTBC. The evaluation of the new antigen (2.5 µg/mL) was against a 1:50 dilution of the M. phlei faced sera. The cut-off point, sensitivity, and specificity determinations of both techniques were by ROC curve analysis. The area under the curve for the I47 ELISA was 0.9 (CI 95%, 0.93-0.97). With a cut-off point of 8.8%, the sensitivity was 84.3% and the specificity 96.6%. The agreement between both techniques was 0.7 (CI 95%, 0.6-0.8). These results indicate a high discriminative capacity to differentiate positive and negative bovine sera of MAP infection with the I47 ELISA. This result would represent an advantage to dispense with the imported kit.

Exploring oxidative stress, immunological and metabolic biomarkers in dairy cows with postpartum pyometra.

Pyometra is a prevalent and severe infectious disease that affects the reproductive systems of cattle worldwide. This study's main goal was to investigate the biomarkers for oxidative stress (OS), adiponectin, leptin and neopterin (NPT) in cows suffering from postpartum pyometra. The study also aimed to determine which bacteria were most commonly implicated in the development of the disease. A total of 74 cows with pyometra were examined and compared to a control group of healthy cows (n = 20). In comparison to the healthy control and post-treatment groups, the pyometra group showed higher mean values of leptin, adiponectin and malondialdehyde (MDA). In contrast, the glutathione (GSH) and superoxide dismutase (SOD) mean values were lower in the pyometra group as compared to the post-treatment and control groups. NPT levels in the post-treatment groups were lower than those in cows with pyometra but comparable to the healthy control group (p > .05). When compared to the other biomarkers, NPT, leptin and adiponectin showed higher sensitivity and specificity in identifying pyometra cases (AUC ≥0.99). The predominant bacterial isolates from the ptomtra-affected cows consisted of Escherichia coli (N = 29; 39.2%), Arcanobacterium pyogenes (N = 27; 36.5%) and Fusobacterium necrophorum (N = 13; 17.6%). Mixed infection was determined in nine samples (12.2%). Conclusively, OS, adiponectin, leptin and NPT play crucial roles in comprehending the development of postpartum pyometra in cows and have the potential to serve as biomarkers for the disease.

The Fur-like regulatory protein MAP3773c modulates key metabolic pathways in Mycobacterium avium subsp. paratuberculosis under in-vitro iron starvation.

Johne's disease (JD) is a chronic enteric infection of dairy cattle worldwide. Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of JD, is fastidious often requiring eight to sixteen weeks to produce colonies in culture-a major hurdle in the diagnosis and therefore in implementation of optimal JD control measures. A significant gap in knowledge is the comprehensive understanding of the metabolic networks deployed by MAP to regulate iron both in-vitro and in-vivo. The genome of MAP carries MAP3773c, a putative metal regulator, which is absent in all other mycobacteria. The role of MAP3773c in intracellular iron regulation is poorly understood. In the current study, a field isolate (K-10) and an in-frame MAP3773c deletion mutant (ΔMAP3773c) derived from K-10, were exposed to iron starvation for 5, 30, 60, and 90 min and RNA-Seq was performed. A comparison of transcriptional profiles between K-10 and ΔMAP3773c showed 425 differentially expressed genes (DEGs) at 30 min time post-iron restriction. Functional analysis of DEGs in ΔMAP3773c revealed that pantothenate (Pan) biosynthesis, polysaccharide biosynthesis and sugar metabolism genes were downregulated at 30 min post-iron starvation whereas ATP-binding cassette (ABC) type metal transporters, putative siderophore biosynthesis, PPE and PE family genes were upregulated. Pathway analysis revealed that the MAP3773c knockout has an impairment in Pan and Coenzyme A (CoA) biosynthesis pathways suggesting that the absence of those pathways likely affect overall metabolic processes and cellular functions, which have consequences on MAP survival and pathogenesis.

Biochemical and molecular characterization of Campylobacter fetus isolates from bulls subjected to bovine genital campylobacteriosis diagnosis in Spain.

BACKGROUND: Bovine genital campylobacteriosis (BGC) is caused by Campylobacter fetus subsp. venerealis (Cfv) including its biovar intermedius (Cfvi). This sexually transmitted disease induces early reproductive failure causing considerable economic losses in the cattle industry. Using a collection of well-characterized isolates (n = 13), C. fetus field isolates (n = 64) and saprophytic isolates resembling Campylobacter (n = 75) obtained from smegma samples of breeding bulls, this study evaluated the concordance of the most used phenotypic (H2S production in cysteine medium and 1% glycine tolerance) and molecular (PCR) methods for the diagnosis of BGC and assessed possible cross-reactions in the molecular diagnostic methods. RESULTS: Characterization at the subspecies level (fetus vs. venerealis) of C. fetus isolated from bull preputial samples using phenotypic and molecular (PCR targeting nahE and ISCfe1) methods showed moderate concordance (κ = 0.462; CI: 0.256-0.669). No cross-reactions were observed with other saprophytic microaerophilic species or with other Campylobacter species that can be present in preputial samples. Whole genome sequencing (WGS) of discrepant isolates showed 100% agreement with PCR identification. For the differentiation of Cfv biovars, comparison of the H2S test (at 72 h and 5 days of incubation) and a PCR targeting the L-cysteine transporter genes showed higher concordance when H2S production was assessed after 5 days (72 h; κ = 0.553, 0.329-0.778 CI vs. 5 days; κ = 0.881, 0.631-1 CI), evidencing the efficacy of a longer incubation time. CONCLUSIONS: This study confirmed the limitations of biochemical tests to correctly identify C. fetus subspecies and biovars. However, in the case of biovars, when extended incubation times for the H2S test (5 days) were used, phenotypic identification results were significantly improved, although PCR-based methods produced more accurate results. Perfect agreement of WGS with the PCR results and absence of cross-reactions with non-C. fetus saprophytic bacteria from the smegma demonstrated the usefulness of these methods. Nevertheless, the identification of new C. fetus subspecies-specific genes would help to improve BGC diagnosis.

Prevalence and spatial distribution of infectious diseases of dairy cattle in Ontario, Canada.

We investigated the prevalence and spatial distribution of selected pathogens associated with infectious diseases of dairy cattle in Ontario, Canada. The cross-sectional study surveyed bulk tank milk for antibodies against bovine leukemia virus (BLV), Mycobacterium avium ssp. paratuberculosis (MAP), and Salmonella Dublin, and for the presence of mastitis pathogens (Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis). Between October 2021 and June 2022, bulk tank milk samples were obtained from every commercial dairy farm in Ontario (n = 3,286). Samples underwent ELISA testing for the presence of BLV, MAP, and S. Dublin antibodies, and quantitative PCR testing for the detection of specific antigens of pathogens associated with mastitis. Bayesian models were used to estimate prevalence, and spatial analysis was carried out to identify regional clusters of high pathogen prevalence. Prevalence varied for different pathogens, and BLV was widespread across dairy farms in Ontario, with an estimated prevalence of 88.3%. The prevalence of MAP, Staph. aureus and S. Dublin in Ontario dairy herds was 39.8%, 31.5%, and 5.1%, respectively. The vast majority of dairy herds in Ontario were free of intramammary infections caused by Strep. agalactiae and M. bovis. Clusters of increased positive test rates were detected for S. Dublin, MAP, and Staph. aureus, indicating potential geographic risk factors for pathogen transmission. For S. Dublin, an area of increased test positivity rates was detected in southwestern Ontario, close to the Canada-United States border where most of the dairy herds in Ontario are located. Conversely, a localized cluster of positive test outcomes involving 14 subdivisions located in the southeastern region of Ontario was detected for Staph. aureus. Findings from our survey highlight the importance of the testing of aggregated samples and conducting spatial analysis as part of disease surveillance programs, and for implementing risk-based trading approaches among dairy producers.

Etiology and epidemiology of digital dermatitis in Australian dairy herds.

Bovine digital dermatitis (BDD) is an important cause of lameness in dairy cows worldwide. However, very little is known about this disease in Australian herds, which are predominantly managed on pasture. The primary objectives of this cross-sectional study were to describe the presence and prevalence of BDD in Australian dairy herds and to characterize the microbiota of healthy skin and M4 lesions of BDD-affected, pasture-managed cows. Cows from 71 dairy herds were examined at milking time to identify the presence of BDD lesions. True prevalence was estimated using Bayesian methods with informative priors for sensitivity and specificity. Biopsy samples (n = 60) were collected from cows with and without BDD lesions in 7 pasture-based herds. The microbiota in the superficial and deep strata of each tissue biopsy were characterized via sequencing of the V3-V4 region of the bacterial ribosomal RNA gene. Lesions were detected in 1,817 (11.5%) of 15,813 cows and in 68 of 71 (95.8%) herds. The median herd-level apparent and true prevalences of BDD were 8.5% and 18.1%, respectively, but prevalences varied considerably between farms. On farms with BDD, M4 lesions accounted for 70% to 100% of all lesions (interquartile range = 95.1%-100%, median = 100%); M2 lesions (i.e., large ulcerative lesions) were observed at low prevalence (<2.2%) in the few herds (7/71, 9.9%) where they were found. There was a significant difference in the composition of the microbiota between healthy skin and M4 lesions but not between superficial and deep tissue layers. Several gut- and effluent-associated bacterial taxa, including Lentimicrobium and Porphyromonas, which have previously been associated with BDD, were abundant in BDD lesions but not in control biopsies. Our study supports the idea that such taxa are involved in, although possibly not essential to, lesion development and persistence in pasture-managed cows in Australia. Our results also suggest that Dichelobacter may contribute to the disease process. We conclude that BDD is likely to occur in most Australian dairy farms, but that further studies are needed to identify its effect on cow welfare and productivity. Further investigation of the etiology of BDD in Australian dairy herds is also necessary to inform prevention and control strategies.

Phenotypic and genotypic assessment of iron acquisition in diverse bovine-associated non-aureus staphylococcal strains.

Although the role of iron in bacterial infections has been well described for Staphylococcus (S.) aureus, iron acquisition in (bovine-associated) non-aureus staphylococci and mammaliicocci (NASM) remains insufficiently mapped. This study aimed at elucidating differences between four diverse bovine NASM field strains from two species, namely S. chromogenes and S. equorum, in regards to iron uptake (with ferritin and lactoferrin as an iron source) and siderophore production (staphyloferrin A and staphyloferrin B) by investigating the relationship between the genetic basis of iron acquisition through whole genome sequencing (WGS) with their observed phenotypic behavior. The four field strains were isolated in a previous study from composite cow milk (CCM) and bulk tank milk (BTM) in a Flemish dairy herd. Additionally, two well-studied S. chromogenes isolates originating from a persistent intramammary infection and from a teat apex were included for comparative purpose in all assays. Significant differences between species and strains were identified. In our phenotypical iron acquisition assay, while lactoferrin had no effect on growth recovery for all strains in iron deficient media, we found that ferritin served as an effective source for growth recovery in iron-deficient media for S. chromogenes CCM and BTM strains. This finding was further corroborated by analyzing potential ferritin iron acquisition genes using whole-genome sequencing data, which showed that all S. chromogenes strains contained hits for all three proposed ferritin reductive pathway genes. Furthermore, a qualitative assay indicated siderophore production by all strains, except for S. equorum. This lack of siderophore production in S. equorum was supported by a quantitative assay, which revealed significantly lower or negligible siderophore amounts compared to S. aureus and S. chromogenes. The WGS analysis showed that all tested strains, except for S. equorum, possessed complete staphyloferrin A (SA)-synthesis and export operons, which likely explains the phenotypic absence of siderophore production in S. equorum strains. While analyzing the staphyloferrin A and staphyloferrin B operon landscapes for all strains, we noticed some differences in the proteins responsible for iron acquisition between different species. However, within strains of the same species, the siderophore-related proteins remained conserved. Our findings contribute valuable insights into the genetic elements associated with bovine NASM pathogenesis.

Proinflammatory CD14highCD16low monocytes/macrophages prevail in Treponema phagedenis-associated bovine digital dermatitis.

Digital dermatitis (DD) is a skin disease in cattle characterized by painful inflammatory ulcerative lesions in the feet, mostly associated with local colonization by Treponema spp., including Treponema phagedenis. The reason why most DD lesions remain actively inflamed and progress to chronic conditions despite antibiotic treatment remains unknown. Herein, we show an abundant infiltration of proinflammatory (CD14highCD16low) monocytes/macrophages in active DD lesions, a skin response that was not mitigated by topical treatment with oxytetracycline. The associated bacterium, T. phagedenis, isolated from DD lesions in cattle, when injected subcutaneously into mice, induced abscesses with a local recruitment of Ly6G+ neutrophils and proinflammatory (Ly6ChighCCR2+) monocytes/macrophages, which appeared at infection onset (4 days post challenge) and persisted for at least 7 days post challenge. When exploring the ability of macrophages to regulate inflammation, we showed that bovine blood-derived macrophages challenged with live T. phagedenis or its structural components secreted IL-1ß via a mechanism dependent on the NLRP3 inflammasome. This study shows that proinflammatory characteristics of monocytes/macrophages and neutrophils dominate active non-healing ulcerative lesions in active DD, thus likely impeding wound healing after antibiotic treatment.

Quantifying and mapping digital dermatitis-associated bacteria in lesion and nonlesion body sites and dairy farm environment.

The source of infection of digital dermatitis (DD), an infectious lameness condition, is still uncertain. In this cross-sectional study, we aimed to identify potential reservoirs of DD bacteria in dairy cattle body sites with different stages of the disease and farm environments. We collected skin swabs from 85 dairy cows from 5 herds, 3 with and 2 without DD, from foot, hock, and udder cleft skin (with lesions or not), saliva, urine, and feces. We also obtained environmental samples. Real-time quantitative PCR targeted Treponema phagedenis, Treponema medium, Treponema pedis, Porphyromonas levii, Bacteroides pyogenes, Fusobacterium necrophorum, and Fusobacterium mortiferum. Digital dermatitis-associated Treponema spp. were exclusively detected in DD-affected herds in DD-foot and other skin lesions, healthy skin, saliva, and environmental samples. In contrast, the non-Treponema spp. were found in samples from both DD-negative and affected herds. As expected, DD lesions had higher bacterial loads than healthy skin. Interestingly, similar counts were observed in udder cleft lesions, indicating a potential opportunistic behavior on compromised skin. None of the targeted species were detected in fecal samples, but P. levii, B. pyogenes, and F. necrophorum were detected in urine. All 7 species were detected in saliva, although in low quantities. No associations were observed between the presence of each bacterial species in DD lesions and urine; however, there was an association between the presence of DD-Treponema spp. in lesions and saliva, hock, and udder skin. Feces and urine do not seem to be a DD bacteria primary source, but saliva and other skin lesions may play a role. Longitudinal studies would improve our understanding of DD-associated bacteria's transient or persistent presence in these sites. Investigating the sources of DD-associated bacteria will guide future interventions to minimize bacterial shedding and transmission, ultimately more effectively reducing bacterial load, transmission, and sources of infection in dairy herds.

Evaluation of the clinical efficacy of racecadotril in the treatment of neonatal calves with infectious diarrhea.

Racecadotril, used as an antidiarrheal drug in humans and some animals such as the dog, inhibits peripheral enkephalinase, which degrades enkephalins and enkephalinase inhibition induces a selective increase in chloride absorption from the intestines. The study material consisted of 46 calves with infectious diarrhea and 14 healthy calves in the age 2-20 days. The calves were divided into eight groups; healthy calves (HG), healthy calves administered racecadotril (HRG), calves with E.coli-associated diarrhea (ECG), calves with E.coli-associated diarrhea administered racecadotril (ECRG), calves with bovine Rotavirus/Coronavirus-associated diarrhea (VG), calves with bovine Rotavirus/Coronavirus-associated diarrhea administered racecadotril (VRG), calves with C. parvum-associated diarrhea (CG) and calves with C. parvum-associated diarrhea administered racecadotril (CRG). Calves in the racecadotril groups received oral racecadotril at a dose of 2.5 mg/kg twice a day for 3 days. A routine clinical examination of all calves was performed. Hemogram and blood gas measurements were made from the blood samples. Standard diarrhea treatment was applied to the HG, ECG, CG, and VG groups. Clinical score parameters such as appetite, feces quality, dehydration, standing and death and some blood gas and hemogram parameters were evaluated to determine the clinical efficacy of racecadotril. Clinical score parameters were determined observationally. Blood gas measurements were performed using a blood gas analyzer. The hemogram was performed using an automated hematologic analyzer. Statistically significant differences were determined in the blood pH, bicarbonate, base deficit, lactate, and total leukocyte count in calves with diarrhea compared to healthy calves. After the treatments, these parameters were found to be within normal limits. At the end of treatment, 42 of the 46 diarrheal calves recovered, while 4 died. We found that racecadotril was effective in improving both clinical recovery and feces consistency in neonatal calves with diarrhea caused by E. coli. As a result, it can be stated that racecadotril, which has an antisecretory effect, is beneficial in the treatment of bacterial diarrhea caused by such as E. coli.

Comparison of blood parameters according to fecal detection of Mycobacterium avium subspecies paratuberculosis in subclinically infected Holstein cattle.

BACKGROUND: Mycobacterium avium subspecies paratuberculosis (MAP) causes a chronic and progressive granulomatous enteritis and economic losses in dairy cattle in subclinical stages. Subclinical infection in cattle can be detected using serum MAP antibody enzyme-linked immunosorbent assay (ELISA) and fecal polymerase chain reaction (PCR) tests. OBJECTIVES: To investigate the differences in blood parameters, according to the detection of MAP using serum antibody ELISA and fecal PCR tests. METHODS: We divided 33 subclinically infected adult cattle into three groups: seronegative and fecal-positive (SNFP, n = 5), seropositive and fecal-negative (SPFN, n = 10), and seropositive and fecal-positive (SPFP, n = 18). Hematological and serum biochemical analyses were performed. RESULTS: Although the cows were clinically healthy without any manifestations, the SNFP and SPFP groups had higher platelet counts, mean platelet volumes, plateletcrit, lactate dehydrogenase levels, lactate levels, and calcium levels but lower mean corpuscular volume concentration than the SPFN group (p < 0.017). The red blood cell count, hematocrit, monocyte count, glucose level, and calprotectin level were different according to the detection method (p < 0.05). The SNFP and SPFP groups had higher red blood cell counts, hematocrit and calprotectin levels, but lower monocyte counts and glucose levels than the SPFN group, although there were no significant differences (p > 0.017). CONCLUSIONS: The cows with fecal-positive MAP status had different blood parameters from those with fecal-negative MAP status, although they were subclinically infected. These findings provide new insights into understanding the mechanism of MAP infection in subclinically infected cattle.

Prevalence of paratuberculosis in cattle based on gross and microscopic lesions in Ethiopia.

BACKGROUND: Paratuberculosis, caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic progressive granulomatous enteritis mainly affecting domestic and wild ruminants worldwide. Although paratuberculosis could be prevail in Ethiopia, there is a scarcity of epidemiological data on paratuberculosis in the country. Thus, this study was conducted to estimate the prevalence of paratuberculosis based on gross and microscopic lesions in cattle slaughtered at ELFORA Abattoir, central Ethiopia. Small intestines and associated lymph nodes of 400 apparently healthy cattle which were slaughtered at ELFORA export abattoir were examined for gross and microscopic lesions of paratuberculosis. The microscopic lesions were classified into four grades (I-IV) based on the type and number of cells infiltrated into the lesion. The prevalence of paratuberculosis was estimated on the basis of gross as well as microscopic lesion of paratuberculosis. RESULTS: The prevalence of paratuberculosis was 11.25% (95% Confidence interval, CI = 0.083-0.148) on the basis of gross lesion. However, relatively lower prevalence (2.0%, 95% CI = 0.01, 0.039) was recorded based on microscopic lesion. The gross lesions were characterized by intestinal thickening, mucosal corrugations and enlargement of associated mesenteric lymph nodes. On the other hand, the microscopic lesions were characterized by granuloma of different grades ranging from grade I to grade III lesions. CONCLUSIONS: The present study indicated the occurrence of paratuberculosis in cattle of Ethiopia based on the detection of gross and microscopic lesions consistent with the lesion of paratuberculosis. The result of this study could be used as baseline information for future studies on the epidemiology and economic significance of paratuberculosis.