Digital Dermatitis Lesions Research Articles

Evaluation of ‘In-Parlour Scoring’ (IPS) to Detect Lameness in Dairy Cows during Milking

The objective of this study was to evaluate the potential of ‘In-Parlour Scoring’ (IPS) as an alternative to locomotion scoring in herringbone, side-by-side, and tandem milking parlours in Austria. Between January and May 2023, a total of 990 observations were conducted on 495 cows across eleven Austrian dairy farms by two investigators working simultaneously but independently of each other. The observation criteria included shifting weight, claw conformation, and obvious disorders of the distal limb. Locomotion scoring was conducted on all cows within 24 h of assessment in the milking parlour using a scale of 1 to 5 (LCS 1: not lame; LCS 5: severely lame). Functional hoof trimming was performed within ten days after IPS. The following indicators were identified as useful for predicting lameness (LCS ≥ 3): shifting weight, abnormal weight distribution, swollen heel, hock joint or interdigital space, skin lesion on the lateral hock, claw position score, digital dermatitis lesions, short dorsal claw wall, and hyperextension of one claw. The reliability of the individual indicators for intra- and inter-rater assessment exhibited considerable variation ((weighted) kappa values: −0.0020–0.9651 and −0.0037–1.0, respectively). The specificity and sensitivity for the prediction of lame cows were calculated to be ≥ 96% and ≤ 24%, respectively. It was demonstrated that a one-time IPS has limited suitability for lameness assessment on Austrian dairy farms with herringbone, side-by-side, and tandem milking parlours.

Benchmarking analysis of computer vision algorithms on edge devices for the real-time detection of digital dermatitis in dairy cows

Digital dermatitis (DD) is a bovine claw disease responsible for ulcerative lesions on the coronary band of the foot. It causes significant animal welfare and economic losses to the cattle industry. Early detection of DD can lead to prompt treatment and decrease lameness. Current detection and staging methods require a trained individual to evaluate the interdigital space on each foot for clinical signs of DD. Computer vision (CV), a type of artificial intelligence for image analysis, has demonstrated promising results on object detection tasks. However, farms require robust solutions that can be deployed in harsh conditions including dust, debris, humidity, precipitation, other equipment issues. The study aims to train, deploy, and benchmark DD detection models on edge devices. Images were collected from commercial dairy farms with the camera facing the interdigital space on the plantar surface of the foot. Images were scored for M-stages of DD by a trained investigator using the M-stage DD classification system. Models were trained to detect and score DD lesions and embedded on an edge device. The Tiny YOLOv4 model deployed on a CV specific integrated camera module connected to a single board computer achieved a mean average precision (mAP) of 0.895, an overall prediction accuracy of 0.873, and a Cohen’s kappa of 0.830 for agreement between the computer vision model and the trained investigator. The model reached a final inference speed of 40 frames per second (FPS) and ran stably without any interruptions. The CV model was able to detect DD lesions on an edge device with high performance and speed. The CV tool can be used for early detection and prompt treatment of DD in dairy cows. Real-time detection of DD on edge device will improve health outcomes, while simultaneously decreasing labor costs. We demonstrate that the deployed model can be a low-power and portable solution for real-time detection of DD on dairy farms. This result is a step towards applying CV algorithms to veterinary medicine and implementing real-time detection of health outcomes in precision farming.

Characterization of the Hoof Bacterial Communities of Active Digital Dermatitis Lesions in Feedlot Cattle.

Digital dermatitis (DD) is a costly hoof infection, causing lameness and pain in feedlot cattle. DD lesions can develop nonlinearly through a series of clinical stages, which can be classified by Dopfer's M-stage scoring system. This widely adopted lesion scoring system recognizes five DD stages, where M1 (early lesion), M2 (acute ulcerative lesion), and M4.1 (chronic proliferative lesion with new developing lesion) are considered active but separate stages of the disease. This study assessed the skin surface microbiota of the active DD lesions of feedlot cattle. The DD lesions from three commercial feedlots were swabbed and then scored according to Dopfer's M-stage scoring system. Swab samples were collected from 12 M2- and 15 M4.1-stage lesions. A total of 21 control swab samples from healthy contralateral feet (DD control) were classified as stage M0. An additional six skin swabs (M0) were collected from completely healthy (CH control) cattle with no lesions. The bacterial communities of active DD lesions (M2 and M4.1) and healthy skin (M0) were profiled using 16S amplicon sequencing. Diversity analyses showed that the hoof bacterial communities of M2 and M4.1 lesions were each distinct from those of M0 skin. However, the bacterial communities between the two active lesion stages were not different from each other. A significant increase in the relative abundance of Spirochaetota and Fusobacteriota and an overall decrease in bacterial diversity contributed to the altered bacterial communities in M2 and M4.1 lesions compared to those of healthy skin (M0). Although stages M2 and M4.1 are considered clinically different stages, the lesion-associated bacterial community is similar between the two active stages.

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.

Comparative analysis of computer vision algorithms for the real-time detection of digital dermatitis in dairy cows

Digital dermatitis (DD) is a bovine claw disease responsible for ulcerative lesions on the planar aspect of the hoof. DD is associated with massive herd outbreaks of lameness and influences cattle welfare and production. Early detection of DD can lead to prompt treatment and decrease lameness. Computer vision (CV) provides a unique opportunity to improve early detection. The study aims to train and compare applications for the real-time detection of DD in dairy cows. Eight CV models were trained for detection and scoring, compared using performance metrics and inference time, and the best model was automated for real-time detection using images and video. Images were collected from commercial dairy farms while facing the interdigital space on the plantar surface of the foot. Images were scored for M-stages of DD by a trained investigator using the M-stage DD classification system with distinct labels for hyperkeratosis (H) and proliferations (P). Two sets of images were compiled: the first dataset (Dataset 1) containing 1,177 M0/M4H and 1,050 M2/M2P images and the second dataset (Dataset 2) containing 240 M0, 17 M2, 51 M2P, 114 M4H, and 108 M4P images. Models were trained to detect and score DD lesions and compared for precision, recall, and mean average precision (mAP) in addition to inference time in frame per second (FPS). Seven of the nine CV models performed well compared to the ground truth of labeled images using Dataset 1. The six models, Faster R-CNN, Cascade R-CNN, YOLOv3, Tiny YOLOv3, YOLOv4, Tiny YOLOv4, and YOLOv5s achieved an mAP between 0.964 and 0.998, whereas the other two models, SSD and SSD Lite, yielded an mAP of 0.371 and 0.387 respectively. Overall, YOLOv4, Tiny YOLOv4, and YOLOv5s outperformed all other models with almost perfect precision, perfect recall, and a higher mAP. Tiny YOLOv4 outperformed all other models with respect to inference time at 333 FPS, followed by YOLOv5s at 133 FPS and YOLOv4 at 65 FPS. YOLOv4 and Tiny YOLOv4 performed better than YOLOv5s compared to the ground truth using Dataset 2. YOLOv4 and Tiny YOLOv4 yielded a similar mAP of 0.896 and 0.895, respectively. However, Tiny YOLOv4 achieved both higher precision and recall compared to YOLOv4. Finally, Tiny YOLOv4 was able to detect DD lesions on a commercial dairy farm with high performance and speed. The proposed CV tool can be used for early detection and prompt treatment of DD in dairy cows. This result is a step towards applying CV algorithms to veterinary medicine and implementing real-time DD detection on dairy farms.

Molecular Screening for Digital Dermatitis-Associated Treponemes in Bovine Ischaemic Teat Necrosis Lesions and Milk in Dairy Cattle

Bovine ischaemic teat necrosis (ITN) is a disease affecting the skin of the teats of dairy cows with an unknown aetiopathogenesis. Digital dermatitis (DD)-associated treponemes have previously been suggested as a potential aetiological agent in ITN, although the sample size was small. The current study, using established PCR techniques, aimed to examine the association with the presence of DD-associated treponemes in a large number of ITN samples from a wider geographical area, and surveyed the potential of milk as an infection reservoir. From 95 ITN lesions, 35.8% (n = 34) were positive for at least one DD-associated treponeme compared with only 5.6% (n = 1) of 18 non-lesioned teats from cows with ITN lesions on a different teat using a nested PCR approach. All 10 age- and production-matched control cows were negative for DD-associated treponemes via PCR. No DD-associated treponemes could be detected from foremilk of cows with (n = 19) and without (n = 31) a DD lesion on the hind feet. DD-associated treponemes could be detected via PCR after incubation in milk for up to 2 h. Therefore, milk does not appear to be a competent reservoir for transmission of DD-associated treponemes. Moreover, in the current study DD-associated treponemes were only detected in a subset of ITN samples, so it is unlikely these opportunistic skin-associated pathogens are the major or sole agent of ITN.

Comparative efficacy of stannous fluoride and zinc sulfate solution to copper sulfate footbath solutions for the treatment and prevention of digital dermatitis in lactating dairy cows

The objective of this study was to determine whether a novel footbath solution containing stannous fluoride (SnF2) was superior to 5% copper sulfate solution for the treatment and prevention of digital dermatitis (DD) in dairy cattle. Study 1 was conducted over 4 weeks in Missouri and involved 34 lactating Holstein-Friesian cows with hind feet DD lesions. Cows in group SF walked through a footbath containing a proprietary formulation of SnF2 once weekly, whereas cows in group CS walked through a 5% CuSO4 footbath once daily for 5 d each week. Study 2 was conducted over 8 weeks in California and involved 40 lactating Holstein-Friesian cows with hind feet DD lesions. Cows in group SF walked through a SnF2 footbath for 3 consecutive days then once a week for the following 7 weeks. Cows in group CS walked through a 5% CuSO4 footbath 3 times each week for 8 weeks. Data collection included lesion type, lesion area, locomotion score, and pain score. Digital dermatitis was actively transmitted in study 1, and lesion area and locomotion scores were lower in group SF than group CS. In contrast, DD was not actively transmitted in study 2, and lesion area and locomotion scores were similar in groups SF and CS. Stannous fluoride delayed the development of active DD lesions in study 1 compared with copper sulfate, with a lower relative risk (0.57, P < 0.001) of a hind foot developing an active DD lesion over 28 d. However, SnF2 decreased the rate that active DD lesions transitioned to M3, M4, or M0 lesions compared with 5% copper sulfate in both studies, with the relative risk of a hind foot with an active DD lesion transitioning to M3, M4, or M0 in group SF being slightly lower in study 1 (0.83, P = 0.042) and study 2 (0.90, P = 0.020) than group CS. Our findings demonstrated that walking cows through a stannous fluoride footbath once per week in a herd undergoing active transmission of infection was more effective in preventing active DD lesions, but less effective in treating active DD lesions, than walking cows through a copper sulfate footbath 4 times per week. The novel SnF2 footbath solution shows promise for controlling DD in dairy herds that want an alternative footbath solution to CuSO4 and are interested in limiting the environmental accumulation of copper.

Evaluation of potassium monopersulfate footbath solution for controlling digital dermatitis in lactating dairy cattle. A randomized clinical trial.

Our objective was to assess potassium monopersulfate as a disinfectant used in footbath to control digital dermatitis (DD) in dairy cows. We hypothesized that a potassium monopersulfate solution would control DD. A 180-day randomized negative controlled trial was conducted in a 265-Holstein free-stall facility. Throughout the trial, foot bathing was performed bi-weekly using a split (left vs. right feet) footbath: one tub filled with 1% potassium monopersulfate (treatment), the other with tap water (control). Digital dermatitis lesions were scored during trimming chute examinations of the unwashed hind heels every 90 days using the modified M-scoring system. Digital dermatitis lesions were re-categorized into four variables: 1) inactive; 2) active; 3) any; 4) inactive or absence of DD lesions. Three longitudinal outcomes were characterized: risks of 1) developing a DD lesion; 2) reactivating an inactive DD lesion; 3) development of an inactive or the absence of the DD lesion. A generalized linear model was used to compare the variables and longitudinal outcomes between treated and control groups. Prevalence of active DD lesions increased from 12.5% to 39.9% between days 0 and 90. This significant increase in prevalence justified the discontinuation of the study on day 90 for ethical reasons. There was no statistical difference between treated and control groups for the first outcome (RR: 1.0; 95% CI: 0.62, 1.7), the second outcome (RR: 1.0; 95% CI: 0.62,–1.7); or the third outcome (RR: 0.88; 95% CI: 0.37, 2.1). A 1% potassium monopersulfate footbath solution appears ineffective to control DD in this study.

Immunohistochemical Demonstration of Mast Cells in Bovine Papillomatous Digital Dermatitis of Holstein-Friesian Dairy Cattle

Mast cells (MC)are unique members of immune system; their location and functions are of great importance in health and disease status. This study aims to evaluate MCs distribution and heterogenity in healthy and digital dermatitis lesions of dairy cattle for the first time. A total of 50 skin samples, 25 healthy and 25 with digital dermatitis (DD) lesions were sampled in Holstein-Friesian dairy cattle. All samples were stained with hematoxylin-eosin (H&amp;E) for microscopic examination and also stained with Toluidine blue for MCs demonstration. Epidermal acanthosis and hyperkeratosis with dermal inflammatory cell infiltrations were in consistent with digital dermatitis lesions. Spirochetal agents were successfully demonstrated with Warthin-Starry staining in 22 out of 25 DD samples. Increased number of mast cell were observed in digital dermatitis samples when compared with healthy skin samples. The average number of intact MCs were 4.6 ± 2 and 9.3 ± 1 in healthy and digital dermatitis samples, respectively. Two-fold increase in the number of intact MCs in digital dermatitis samples was observed. Degranulated mast cell numbers in tissue sections were also higher in digital dermatitis samples and 4.25-fold increase was recorded in affected skin samples. Immunophenotype of MCs in skin samples were identified by immmunohistochemical stainings with anti-tryptase and chymase antibodies. Only tryptase positive MCs were observed in healthy and DD samples. In the statistical analysis, differences in the mean intact and degranulated MCs were found to be significant (mean intact: p&lt;0.05, mean degranulated: p&lt;0.01). Our results possibly suggest that MCs may have important roles in the pathogenesis of bovine digital dermatitis.

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-1β 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.

Risk factors for chronic perforating skin lesions in the area of the digits in cattle on Swiss alpine pastures

Diseases of the digits often occur in cattle on larger cattle mountain pastures. In the late spring 2020, at the time of the ascent of 1554 cattle to 11 high altitude alpine pastures in the Lower Engadine region, lesions in the area of the digits were clinically assessed and documented. 254 cattle were of non-cantonal and 1300 of local origin (Lower Engadine; postal code CH-75XX). Skin lesions in the area of the digits, identified as digital dermatitis (DD; Mortellaro's disease), were further classified according to the DD scoring system. Nonspecific skin lesions with clinical evidence of granulation tissue formation were termed chronic penetrating skin lesions (CPSL). At the end of the alpine pasturing season, in the early fall (descent of cattle from the alpine pastures), the procedure was repeated, and biopsies were taken from randomly selected cattle with CPSL. Digital dermatitis lesions were found in 34 of 1551 cattle at ascent, but no case of CPSL was found at that time. At descent, 19 of 1529 cattle had DD lesions and 88 cattle had CPSL. The clinical appearance of the CPSL was consistent with chronic skin lesions caused by penetrating skin lacerations. Histologically, the majority of the CPSL were classified as chronic hyperplastic dermatitis with granulation tissue formation. In all CPSL biopsies examined by PCR, Fusobacterium necrophorum and Porphyromonas levii, but neither Dichelobacter nodosus nor the tested Treponema species were detected. Fluorescence in situ hybridization revealed a negative result for Treponema species in all biopsies. In the regression analysis, cattle in the age group of 365 to 730 days had an increased risk for the presence of CPSL compared to the age group of 160 to 365 days (odds ratio (OR) = 4,95; confidence interval (CI) = 1,97-12,43). Holstein cattle had an increased risk of developing CPSL compared to Brown cattle (OR = 2,92; CI = 1,46-5,86) and cattle of non-cantonal origin showed a massively higher risk compared to local cattle (OR = 10,59; CI = 5,79 - 19,37). The statistically significant associations found in the present study can be taken into account in the selection of animals for summer pasturing on high altitudes in the future in order to reduce the prevalence of CPSL and consequently reduce the antimicrobial use. Spread of DD during the alpine pasturing season within the cattle groups examined was not found.

An In-House ELISA for Treponema Antibodies in Bulk Milk as Part of a Monitoring Tool for Claw Health in Dairy Herds.

Digital dermatitis (DD) is a painful inflammation at the coronary band of the claws, a major cause of lameness in cattle and associated with infections with several Treponema spp. Clinical inspection of the feet is the best way to diagnose DD, but this is laborious and stressful for cattle. A simple diagnostic tool was developed to monitor DD prevalence at the herd level. An antibody ELISA based on antigens from four different Treponema spp. has been developed and validated in two field studies. In one study, bulk milk and individual milk samples of seven dairy herds, of which clinical claw scores were obtained, were tested. In the second study, bulk milk was tested from 110 herds of which clinical scores were obtained. A weak correlation between clinical scores of cows and the ELISA results in individual milk samples was observed. The ELISA response in bulk milk was higher in herds with higher mean clinical scores. Using the ELISA results in bulk milk, herds with a low or high proportion of cattle with DD lesions could be distinguished. This ELISA is useful to obtain insight into the DD status at the herd level, and is nowadays being used in a claw health monitoring program for dairy cattle in the Netherlands.

Efficacy of quaternary ammonium salt-based disinfectant or chelated copper-zinc footbath solution in the treatment of digital dermatitis on one research dairy farm in Taiwan.

Footbaths can be used to manage digital dermatitis (DD), a common cause of lameness in dairy cattle. Copper sulfate and chelated copper-zinc (CZS) solutions in footbaths are potentially harmful to the environment. To determine if a quaternary ammonium salt-based disinfectant (QASD) footbath is as effective as a chelated CZS solution in controlling DD in dairy cows. Fifty-one lactating Holstein cows were randomly assigned to one of two treatment groups, with DD status based on the M-stage scoring system and locomotion score balanced between treatment groups. The groups were treated with a 1% QASD or a 2.5% chelated CZS. Footbaths were performed once per week for 15 weeks. Logistic regression was used to analyse clinical improvement. All cows received appropriate medical treatment for DD and other hoof diseases. Clinical improvement rates were 67% in the QASD group and 38% in the CZS group (p = 0.03). Logistic regression analysis showed that the odds (95% confidence interval) for clinical improvement rate in the CZS group were 0.30 (0.095-0.948) times that of the QASD group (p = 0.04). The M0 score in the QASD and CZS groups increased significantly (p < 0.05) at the end of the 15 week study period. In the QASD group, the proportion of M2, M3 and M4 scores were significantly decreased (p < 0.05). Over a 15 week period, QASD for footbathing was associated with a lower prevalence of active DD lesions than when using CZS.

A cross-sectional study of the prevalence of lameness and digital dermatitis in dairy cattle herds in Egypt

BackgroundLameness is a significant problem for the dairy industry worldwide. No previous studies have evaluated the prevalence of lameness or digital dermatitis (DD) in dairy cattle herds in Egypt. A total of 16,098 dairy cows from 55 dairy herds in 11 Egyptian governorates underwent visual locomotion scoring using a 4-point scoring system. Cows that had a lameness score ≥ 2 were considered clinically lame. Following manure removal with water and using a flashlight, the cows’ hind feet were examined in the milking parlour to identify DD lesions and classify with M-score. Furthermore, each cow was assigned a hock score (a 3-point scale) and a hygiene score (a 4-point scale). The cow-, within-and between-herd prevalence of lameness and DD and associated 95% confidence intervals (CI) were calculated. The prevalence of hock lesions and poor cow hygiene was also calculated.ResultsOf the examined cows, 6,883 were found to be clinically lame (42.8%, 95% CI = 42.0–43.5%). The average within-herd prevalence of lameness was 43.1% (95% CI = 35.9–50.3%). None of the dairy herds recruited into the study were found to be free from clinical lameness. The average within-herd prevalence of DD was 6.4% (95% CI = 4.9–8.0%). The herd-level prevalence of DD was 92.7% (95% CI = 85.9–99.6%). Active DD lesions (M1, M2, M4.1) were identified in 464 cows (2.9%) while inactive lesions (M3, M4) were identified in 559 cows (3.5%). The within-herd prevalence of hock lesions (score 2 or 3) was 12.6% (95% CI = 4.03–21.1%) while a severe hock lesion had within-herd prevalence of 0.31% (95% CI = 0.12–0.51%). Cow-level prevalence of hock lesions was 6.2% (n = 847, 95% CI = 5.8–6.2%). The majority of examined cows had a hygiene score of 4 (n = 10,814, prevalence = 70.3%, 95% CI = 69.5–71%).ConclusionsThe prevalence of lameness was higher than prevalence estimates reported for other countries which could be due to differing management and/or environmental factors. DD was identified at lower prevalence in most herds but with high herd-level prevalence. Poor cow hygiene was notable in most herds. Measures to reduce the prevalence of lameness and to improve cow hygiene in dairy cattle herds in Egypt are therefore needed.

Broad-spectrum infrared thermography for detection of M2 digital dermatitis lesions on hind feet of standing dairy cattle.

Low-effort, reliable diagnostics of digital dermatitis (DD) are needed, especially for lesions warranting treatment, regardless of milking system or hygienic condition of the feet. The primary aim of this study was to test the association of infrared thermography (IRT) from unwashed hind feet with painful M2 lesions under farm conditions, with lesion detection as ultimate goal. Secondary objectives were to determine the association between IRT from washed feet and M2 lesions, and between IRT from unwashed and washed feet and the presence of any DD lesion. A total of 641 hind feet were given an M-score and IRT images of the plantar pastern were captured. Multivariable logistic regression analyses were done with DD status as dependent variable and maximum infrared temperature (IRTmax), lower leg cleanliness score and locomotion score as independent variables, and farm as fixed effect. To further our understanding of IRTmax within DD status, we divided IRTmax into two groups over the median value of IRTmax in the datasets of unwashed and washed feet, respectively, and repeated the multivariable logistic regression analyses. Higher IRTmax from unwashed hind feet were associated with M2 lesions or DD lesions, in comparison with feet without an M2 lesion or without DD, adjusted odds ratio 1.6 (95% CI 1.2-2.2) and 1.1 (95% CI 1.1-1.2), respectively. Washing of the feet resulted in similar associations. Dichotomization of IRTmax substantially enlarged the 95% CI for the association with feet with M2 lesions indicating that the association becomes less reliable. This makes it unlikely that IRTmax alone can be used for automated detection of feet with an M2 lesion. However, IRTmax can have a role in identifying feet at-risk for compromised foot health that need further examination, and could therefore function as a tool aiding in the automated monitoring of foot health on dairy herds.

The bovine foot skin microbiota is associated with host genotype and the development of infectious digital dermatitis lesions

BackgroundBovine Digital Dermatitis (BDD) is a prevalent infectious disease, causing painful foot skin lesions and lameness in cattle. We describe herein the bovine foot skin microbiota and its associations with BDD using 16S rRNA gene amplicon and shotgun metagenomic sequencing on samples from 259 dairy cows from three UK dairy farms.ResultsWe show evidence of dysbiosis, and differences in taxonomy and functional profiles in the bovine foot skin microbiome of clinically healthy animals that subsequently develop BDD lesions, compared to those that do not. Our results suggest that taxonomical and functional differences together with alterations in ecological interactions between bacteria in the normal foot skin microbiome may predispose an animal to develop BDD lesions. Using genome-wide association and regional heritability mapping approaches, we provide first evidence for interactions between host genotype and certain members of the foot skin microbiota. We show the existence of significant genetic variation in the relative abundance of Treponema spp. and Peptoclostridium spp. and identify regions in the bovine genome that explain a significant proportion of this variation.ConclusionsCollectively this work shows early changes in taxonomic and functional profiles of the bovine foot-skin microbiota in clinically healthy animals which are associated with subsequent development of BDD and could be relevant to prevention of disease. The description of host genetic control of members of the foot skin microbiota, combined with the association of the latter with BDD development offer new insights into a complex relationship that can be exploited in selective breeding programmes.ApfTUdsqPmkzyTqVTTd38-Video

Treatment of digital dermatitis using salicylic acid in European bison (Bison bonasus) reveals promising results.

Digital dermatitis (DD) associated with the presence of multiple Treponema spp. was recently described for the first time in European bison (Bison bonasus). DD is characterized by skin inflammation in the distal foot area in various ungulates. The objective of this proof of concept study was to test a treatment protocol adopted from cattle for its applicability in this wildlife species using five animals. Keratolytic salicylic acid paste was administered topically under bandages for seven days to enable removal of the affected skin. All interventions were performed under general anesthesia. To evaluate the treatment efficacy, photographs and biopsies were taken pre- and post-treatment. The biopsies were examined histologically, by PCR for the presence of different bacterial species, by Treponema-specific fluorescent in situ hybridization (FISH), and by transmission electron microscopy. Based on photographs, complete clinical healing of the 15 feet with macroscopical DD lesions was achieved. Histological examination showed mild to moderate dermatitis in 17/20 feet before, and in 12/20 feet after treatment. 17/20 feet were Treponema spp. PCR positive before, and none was positive after treatment. Dichelobacter nodosus, Fusobacterium necrophorum, and Porphyromonas levii could not be detected in any of the samples. By FISH and electron microscopy, Treponema spp. could be visualized in the stratum corneum before, but not after treatment. These results suggest that this treatment method can be applied as standard practice prior to transporting DD affected European bison to prevent the spread of this contagious disease.

Detection and quantification of bacterial species DNA in bovine digital dermatitis lesions in swabs and fine-needle aspiration versus biopsies.

Digital Dermatitis (DD) is a polymicrobial disease characterized by ulcerative lesions on the heel bulb of cattle and for which, despite being reported almost 50 years ago, information on the causative agent is still lacking. Tissue biopsies are regularly collected to identify bacterial presence-absence and their relative abundance in the microbiome, with sufficient evidence for the high abundance of species of Treponema spp. and other anaerobes in lesions. However, it is unclear what the potential of less-invasive sampling methods is for bacterial detection and quantification. This study aimed to test whether less-invasive sampling techniques, such as swabs and fine-needle aspiration (FNA), can be a convenient alternative to tissue biopsies in detecting and quantifying seven DD-associated bacteria in active, ulcerative DD lesions by qPCR. Twenty-two M2 DD lesions were collected using corresponding swabs, aspirates, and biopsies from dairy cows. Presence/absence and quantities of Treponema phagedenis, Treponema medium, Treponema pedis, Porphryromonas levii, Bacteroides pyogenes, Fusobacterium necrophorum, and Fusobacterium mortiferum were correlated, and Bland-Altman plot, McNemar's test, and Cohen's kappa coefficient were used to calculate the agreement among the methods. The quantities of all species were larger in swabs and smaller in aspirates compared to biopsies; however, the differences in bacterial enumeration observed between biopsies and swabs were smaller than in biopsies and aspirates. A strong correlation was observed between the quantity of T. pedis, T. medium, P. levii, and F. mortiferum in biopsies, swabs, and FNA. Yet, T. phagedenis presented the smallest difference between biopsies and swabs, followed by T. pedis and T. medium. In conclusion, swabs, aspirates, and biopsies were equal in their capacity to detect Treponema species based on the good agreement for bacteria presence/absence, with a more limited agreement for the other anaerobes, which were more often present in M2 lesions swabs by qPCR. Bacterial numbers were higher in swabs and lower in aspirates compared to biopsies, with the amounts of treponemes in swabs being closer to biopsies than in aspirates to biopsies. Therefore, aspirates were less suitable for bacterial quantification in DD lesions compared to the other methods.

PSXIV-11 Microbial Characterization of Digital Dermatitis and Foot rot in Feedlot Cattle

Abstract Lameness is a significant health issue in feedlot cattle, having major economic, labor, and welfare implications. Digital dermatitis (DD), a lesion of the plantar surface of the foot, and foot rot (FR), which affects the interdigital cleft, are common infectious causes of feedlot lameness with bacterial origins. These hoof lesions can occur alone or in combination in the same hoof (DD+FR). Over a one-year period (2019-2020), 208 hoof swabs were obtained from cattle with FR (n = 55), DD (n = 18), and DD+FR (n = 29), and 5 completely healthy cattle (controls) from three southern Alberta commercial feedlots. 16S rRNA gene sequencing was used to characterize the bacterial microbiota of DD, FR, and DD+FR lesions relative to corresponding healthy skin controls found within the same affected animals. DD and FR lesion microbiotas showed reduced diversity compared with corresponding control skin. Multiple Treponema (members of Spirochaetaceae Family) species were differentially abundant in DD lesions compared with contralateral control skin. FR lesions are characterized by an abundance of Fusobacterium necrophorum and Porphyromonas levii, compared with contralateral control skin. The microbiome of DD+FR lesions was similar to FR lesions, where F. necrophorum and P. levii were increased compared with contralateral control skin. Other differentially abundant taxa (Helcococcus, Succiniclasticum spp.) found in FR and DD+FR lesions had been previously associated with DD, suggesting there may be an overlap of bacteria that have a role in both types of hoof lesions. The findings support previous literature showing that FR and DD are polybacterial in nature. The identification of novel bacterial species of DD and FR lesions could contribute information for the development of more targeted and effective prevention and treatment strategies. A novel finding of the sequencing analysis for hooves with concurrent DD and FR infection was characterized.