First report of the within-farm prevalence of bovine digital dermatitis in Chinese Holstein dairy cows in Jiangsu, China: A Bayesian modelling approach.

Digital dermatitis is one of the most important causes of lameness in dairy cattle, particularly in housed, intensively-managed cattle. The number of modern intensive dairy farms in China has increased markedly in recent years; however, we lack research on digital dermatitis in Chinese dairy cattle. This preliminary study aimed to estimate the prevalence of digital dermatitis on three conveniently selected farms in Jiangsu, China. The washed hind feet of all lactating cows on all three farms were examined during milking with the aid of a mobile phone light source. True prevalence was then estimated from the apparent prevalence using a Bayesian superpopulation approach to account for the imperfect nature of identifying digital dermatitis in cows during milking. Despite none of the farms having thought it necessary to implement routine digital dermatitis monitoring or control, the disease was found on all three sampled farms. All lesions observed were either chronic M4 or M4.1 type-lesions, with no M2 lesions (i.e. acute ulcerated lesions) observed. The estimated true prevalences on the farms were 7.3% (95% credible interval [CrI]: 5.4%-9.6%), 8.3% (95%CrI: 6.3%-10.8%), and 29.8% (95%CrI: 22.9%-37.2%).

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.

Evaluation of selected risk factors for different stages of digital dermatitis in Dutch dairy cows.

Digital dermatitis (DD) is a painful infectious disease in dairy cattle that causes ulcerative lesions of the skin just above the coronary band, mainly of the hind legs. Estimates for DD prevalence at cow level in the Netherlands range from 20% to 25%. In this study, risk factors for the various stages of DD were identified and quantified. The hind legs of 6766 cows on 88 farms were scored by trained interns, using the M-scoring system (M0-M4.1). Farms in this study were a convenience sample, based on the prevalence of DD as recorded at the latest herd trim, geographical location and willingness of the farmers to participate. A survey with questions about cow environment and herd management was conducted by the intern at the day of scoring. The data were collected between August 2017 and January 2018. DD was found on 38.6% of the scored legs; 49.8% of the cows had DD on at least one leg and M4 was the most frequent stage (20.9%). Not removing manure on a regular basis resulted in lower odds for M2, M4 and M4.1 compared to cleaning by automatic scrapers ten times a day or more (odds ratio [OR]= 0.16, 0.49 and 0.18, respectively). The odds for M2 and M4 lesions were higher in cows aged 3-5 years than in first-calved cows (OR> 1.5 and > 1.7, respectively). Rubber flooring in the passageways resulted in lower odds for both M1 and M2 (OR, 0.06 and 0.32, respectively). Prophylactic use of footbaths treatment with an alternative active compound resulted in significant higher odds for M4 lesions than formalin and a combination of formalin and copper sulphate (OR= 1.69 and 2.04 respectively). The odds for an M4.1 lesion were lower in cows from smaller herds (n = 50-100) compared to large herds (n >100; OR= 0.67).

Evidence of novel Treponema phylotypes implicated in contagious ovine digital dermatitis and association of treponemes with major lameness causing foot pathogens.

In this study 269 swabs collected from 254 ovine foot lesions and 15 apparently healthy ovine feet were screened by PCR for the presence of major lameness causing foot pathogens viz. Treponema species, D. nodosus, F. necrophorum and T. pyogenes with the presumption that ovine foot lesion positive for Treponema species alone or in association with other three pathogens were categorized as contagious ovine digital dermatitis (CODD). While samples positive for D. nodosus alone or its combination with F. necrophorum and T. pyogenes were considered as footrot (FR) and samples in which F. necrophorum or T. pyogenes was found either alone or in combination were considered as interdigital dermatitis (ID). The overall occurrence of Treponema sp. in ovine foot lesions was 48.0%, and ranged from 33 to 58%. In Treponema positive samples D. nodosus, F. necrophorum and T. pyogenes were present in 34 (27.4%), 66 (54.4%) and 84 (68.5%) in contrast to Treponema negative samples in which these were present in 15 (11.1%), 20 (14.12%) and 17 (12.6%) samples, respectively. The data signifies that Treponema sp. are significantly associated with these foot pathogens and their different combinations with Treponema sp. influence the severity of CODD lesion. The identification of Treponema phylotypes was done by sequencing the 16S rRNA gene fragment of ten representative samples. Out of ten sequences, four (Trep-2, Trep-4, Trep-7 and Trep-10) were identical to Treponema sp. phylotype 1 (PT1) that belongs to phylogroup T. refringens-like, one sequence (Trep-1) was genetically close (90% sequence homology) to Treponema brennaborense while five sequences (Trep-3, Trep-5, Trep-6, Trep-8 and Trep-9) matched with uncultured bacterium clones of treponemes forming separate monophyletic group in phylogenetic tree and could represent new digital dermatitis phylogroup presently containing five ovine specific phylotypes. This is the first report on the presence of Treponema phylotypes other than three digital dermatitis (DD) Treponema phylogroups viz. T. phagedenis-like, T. medium/T. vincentii-like, and T. pedis-like that are frequently detected in CODD lesions. Metagenomic analysis of two representative samples revealed the abundance of genus Treponema in CODD lesion while this genus was absent in swab collected from clinically healthy foot suggesting that it might play primary role in producing CODD. These findings may further aid in understanding the etiopathogenesis of CODD and could help to develop appropriate treatment and mitigation strategies to combat the disease.

Development of a multiplex quantitative PCR assay for simultaneous detection of Treponema phagedenis, Treponema pedis, Treponema medium, and 'Treponema vincentii' and evaluation on bovine digital dermatitis biopsies.

Bovine digital dermatitis (BDD) is a contagious foot disease with worldwide occurrence in dairy cattle. The disease causes lameness and reduced animal welfare as well as economic losses for the farmer. The aetiology is not fully established but associations have been made with Treponema spp. Today, BDD diagnosis is mainly based on visual inspection of cattle feet, therefore this study aimed to develop a multiplex quantitative PCR (qPCR) assay targeting Treponema phagedenis, Treponema pedis, Treponema medium, and 'Treponema vincentii' to aid in diagnosis. The assay was tested for specificity on 53 bacterial strains and in silico on 168 Treponema spp. genomes, representative of at least 24 species. In addition, 37 BDD biopsies were analysed and the results compared to another qPCR assay published during the study period, which we modified by combining into a multiplex qPCR. The qPCR developed herein had a detection limit of 10 copies of each target species per PCR reaction. Both qPCR assays showed 100% specificity when tested on bacterial strains, but the qPCR developed in this study detected 3.4% more T. phagedenis-positive biopsies of lesion category M1-M4.1 than the modified assay. To conclude, the developed qPCR assay detecting T. phagedenis, T. pedis, T. medium, and 'T. vincentii' has high analytical sensitivity and specificity and provides a useful complementary tool for diagnosis and epidemiological studies of BDD. The assay could possibly also be used for contagious ovine digital dermatitis (CODD) as similar bacteriological profiles have been suggested for BDD and CODD, especially regarding certain Treponema spp.

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

BACKGROUND: Lameness 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. RESULTS: Of 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%). CONCLUSIONS: The 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.

Farm-level risk factors for digital dermatitis in dairy cows in mountainous regions.

Reduction of risk factors for bovine digital dermatitis (BDD) is crucial in current disease control. However, risk factors that might arise especially in mountainous regions are unknown until now, and an adapted BDD control program is consequently missing. The objective of this observational case-control study was to identify farm-level risk factors for BDD in dairy herds in mountainous regions. To investigate predictors for the occurrence of BDD, 100 farms were visited and information about herd characteristics and management practices, potentially relevant explanatory variables for either introduction or establishment of BDD, were gathered by completing a questionnaire with the farmer or herd manager. Within-herd prevalences of BDD assessed during 3 routine claw trimmings with an interval of 6 mo before the survey were used to define cases (BDD within-herd prevalence of ≥26% during each claw trimming) and controls (no BDD cases in each of the 3 routine claw trimmings before the survey). Data were analyzed using 2 separate binomial generalized linear models according to either establishment or introduction of BDD. After prescreening, 15 of 23 explanatory variables were included in the final analysis, which showed 3 variables related to introduction and establishment, each being significantly associated with the occurrence of BDD within a farm. Results of model 1 (i.e., aspects related to BDD introduction) revealed that access to mountain pastures during the summer season (odds ratio, 95% confidence interval: 0.12, 0.04-0.35), participation in dairy shows (0.32, 0.11-0.94), and the number of new animals introduced into the farm during the last 2 yr (1.28, 1.12-1.52) were significantly associated with the occurrence of BDD. Model 2 (i.e., aspects related to BDD establishment) showed that cows kept in freestalls were at higher risk for BDD compared with those kept in tiestalls (20.65, 1.59-649.37). Furthermore, number of days between diagnosis and treatment of a BDD lesion (10.31, 3.55-81.21) and the amount of concentrate feeding (median 5 kg) per cow and day (7.72, 2.46-6.47) were positively associated with BDD occurrence. In conclusion, the findings of this study provide a set of risk factors that are associated with BDD status within herds in mountainous regions. These results may help in development of adapted control programs for BDD in dairy cows.

A case-control study regarding factors associated with digital dermatitis in Norwegian dairy herds.

BACKGROUND: Digital dermatitis (DD) is a contagious bovine foot disease causing painful lesions, lameness, and reduced animal welfare. Previous studies indicate a complex aetiology of the disease. The aim of this study was to compare DD negative and DD positive herds to identify factors associated with DD in Norwegian dairy herds by analysing data obtained in a questionnaire and data recorded in the Norwegian Dairy Herd Recording System (NDHRS). The questionnaire was e-mailed to the owners of all 380 herds recorded with DD in 2019 and to 1530 randomly selected herds with no recordings of DD. Altogether 559 dairy herds were included in the final study population, of which 113 was classified as DD positive (≥ one cow recorded with DD in NDHRS) and 446 as DD negative. When stratified by housing system, the ratio between DD positive and negative herds was 108/281 in free stalls and 5/165 in tie stalls. Multilevel logistic regression was used to model the association between potential risk factors and variables related to the detection and diagnosis of DD, and the outcome in the free-stall population. Geographical area (county) was included in the model as a random effect. RESULTS: In the final study population 108/113 (96%) of the DD positive herds were housed in free stalls versus 5/113 (4%) in tie stalls. The free-stall herds' DD status was associated with purchase of cattle during the last 5 years (baseline: 0 animals, OR = 2.30 for category 12-27 animals, OR = 4.34 for 28-52 animals, and OR = 5.39 for ≥ 53 animals). The DD status was also associated with claw trimming frequency (Baseline: 1 < 2/year, OR = 0.41 for category < 1/year, and OR = 4.09 for ≥ 3/year), whether the claw trimming was done by a certified professional trimmer or not (baseline: ≤ 90% of the cows, OR = 3.98 for category ≥ 90% of the cows), cleaning of feet in the chute before trimming (baseline: no cleaning, OR = 1.98 for category cleaning), and alley flooring (baseline: slatted floor, OR = 2.36 for category solid floor). CONCLUSIONS: Digital dermatitis was far more frequent in Norwegian dairy herds housed in free stalls versus those housed in tie stalls. In the free-stall herds purchase of cattle, increasing trimming frequency, use of certified professional trimmer, cleaning of the feet in the chute, and solid flooring in the alleys were associated with increased odds of recorded DD.

Prevalence of bacterial species associated with ovine footrot and contagious ovine digital dermatitis in Swedish slaughter lambs.

BACKGROUND: Ovine footrot and contagious ovine digital dermatitis (CODD) are contagious mixed bacterial infections with major impacts on animal health and production. In Sweden, ovine footrot and CODD were first detected in 2004 and 2019, respectively. In 2009, a voluntary control programme for footrot was established, and a prevalence study in slaughter lambs was conducted, however, the distribution of footrot and CODD-associated bacteria is still unknown. This study examined the prevalence of Dichelobacter nodosus, Fusobacterium necrophorum and Treponema spp., as well as the current prevalence of footrot and CODD, in Swedish slaughter lambs. RESULTS: A total of 2048 feet, from 512 slaughter lambs, were collected from eight slaughterhouses throughout Sweden in autumn 2020. All feet were visually examined for lesions of footrot and CODD and sampled for subsequent real-time polymerase chain reaction (PCR) analysis. Nine lambs (1.8%) had at least one foot affected with footrot (footrot score ≥ 2). A CODD grade 1 lesion was detected in a single lamb (0.2%). The prevalence of D. nodosus, F. necrophorum and Treponema spp. was 6.1%, 7.6% and 90.6%, respectively. The D. nodosus detected were benign strains. CONCLUSIONS: The prevalence of footrot in Swedish slaughter lambs has been significantly reduced, from 5.8 to 1.8%, during the past 11 years. This indicates that preventive measures, such as the national control programme and elimination of footrot from affected flocks, have been effective. A single lamb (0.2%) was found with a CODD lesion (grade 1). In Sweden, benign rather than virulent strains of D. nodosus seem to be the most common. Neither D. nodosus nor F. necrophorum were widespread among Swedish slaughter lambs, but both were more likely to be found in lambs with footrot. Treponema spp. was very commonly found in lambs with and without footrot, but there is a lack of information on the individual Treponema spp. present in Swedish slaughter lambs and their potential pathogenicity.

Status of claw recordings and claw health in Danish dairy cattle from 2013 to 2017.

Since 2009, Danish claw trimmers have been able to record claw health digitally during trimming. The records are owned by the farmer and can be used locally in the herd and on a large scale by breeding organisations to improve claw health. The objective of this study was to describe data on claw recording routines and describe the prevalence of digital dermatitis (DD), interdigital hyperplasia (IH), sole ulcer (SU) and white line abscess (WLA) recorded by claw trimmers (TrimmerID) at trimming. More than 5.18 million records of cows with claw recordings and 2.75 million records of claw trimming with 2.4 million concurrent claw diseases from 62 TrimmerIDs from 705,803 animals from 1635 herds over a 5-year period from 2013 to 2017 were included in the dataset. Data on cow level was used for the descriptive statistics. The data was restricted to, and grouped by, heifers from 12 months of age, first, second and third or older parity cows from the breeds Holstein, Danish Red Dairy, Jersey and crossbreds. The number of recorded trimmings per TrimmerID per year varied from 132 to 48,040 with a mean of 9556 and increased during the period studied. The overall prevalence across breed and parity groups of DD, IH, SU and WLA was 21%, 6%, 7% and 3%, respectively. The prevalence of the lesions remained quite constant during the 5-year period. DD was recorded in 95% of the herds in 2017. The prevalence of IH, SU and WLA increased with increasing parity. Digital recording of claw lesions may be a good indicator of claw health. However, the recording routines and quality of the recordings must be considered.

First report on outbreaks of contagious ovine digital dermatitis in Sweden.

BACKGROUND: Contagious ovine digital dermatitis (CODD) is considered widespread in the United Kingdom but was only recently reported in mainland Europe, as one outbreak in Germany. The disease can cause severe lameness in sheep and, if left untreated, can lead to total avulsion of the hoof capsule. CODD is considered to have multifactorial and polymicrobial aetiology, in which Treponema medium/Treponema vincentii phylogroup, Treponema phagedenis phylogroup and Treponema pedis are believed to play a significant role. Footrot and CODD have a close connection and footrot is considered an important risk factor for CODD. CASE: Lameness, mainly in lambs aged 1.5 months, was reported on a farm in Sweden in spring 2018. The animals showed no signs of footrot and the causative agent, Dichelobacter nodosus, was not found. CODD was suspected but not confirmed, and the clinical signs subsided when the animals were turned out to pasture. In February 2019, young lambs and ewes were lame again and this time CODD was diagnosed. After treatment, the whole flock was slaughtered later in 2019 due to CODD. In autumn 2020, CODD was diagnosed on another Swedish farm, this time as part of a mixed infection with D. nodosus. The animals were treated with footbaths in zinc sulphate 10% by the farmer, but lameness recurred soon afterwards. The animals were treated, but ultimately the whole flock was slaughtered. No connection was found between the two farms. CONCLUSION: The first two outbreaks of CODD in Sweden have been diagnosed and are described in this case report. If it spreads, CODD could have a negative impact on the Swedish sheep industry in terms of animal welfare, production and antibiotic use.

Prevalence of digital dermatitis using mirror scoring in Finnish freestall dairy herds.

Digital dermatitis (DD) is a severe bacterial hoof disease found worldwide. The disease can be classified into 5 different stages, denoted as M1 to M4 and M4.1, by clinical examination. The main objective of this study was to estimate prevalence of DD lesions in Finnish freestall dairy cattle population through hind feet inspection of standing cows with a mirror. Another aim was to estimate the sensitivity and specificity of mirror scoring on standing cows in a pen or in a milking parlor without washing the feet. Three veterinarians visited 81 randomly selected herds across the country. During the herd visits, hind feet of standing cows (n = 7,010) were scored with a mirror without washing the feet, either when the cows were standing in a pen (n = 4,992) or in the milking parlor (n = 2018). In total, 128 cows (111 from pen and 17 from milking parlor) including 256 feet were chosen with cross-sectional sampling and scored in a trimming chute. Animal-level sensitivity for scoring M2 lesions with a mirror was 55% and specificity was 97%; for all active DD lesions (M1, M2, or M4.1), sensitivity was 36% and specificity was 96%. Sensitivity for scoring any DD lesions was 90% and specificity was 82%. The bias-corrected sensitivity and specificity for scoring any DD lesions were 79% and 92%, respectively. The bias-corrected sensitivity and specificity for scoring M2 DD lesions were 10% and 100%. We found M2 lesions in 12.1% of the study herds, and true herd-level prevalence was the same. Altogether, 33.3% (true prevalence 28.4%) of the herds had either M1, M2, or M4.1 DD lesions. However, only 0.7% (true prevalence 5.4%) of cows in total had active M2 lesions. The within-herd prevalence of M2 lesions (in herds where at least 1 cow had a M2 lesion) was 5.7% and varied between 0.4% and 18.8%. Herds with active DD lesions also had more any DD lesions than herds without active DD lesions. The herd-level prevalence was higher than previously thought, with only 1 herd without any DD lesions. However, the animal-level prevalence of active DD lesions was relatively low. Farmers and veterinarians need to be informed of the disease and possible control measures. Because of the low within-herd prevalence, the control of the disease might be easier than in countries where DD is widespread. Further studies are needed to identify factors associated with DD prevalence in Finnish dairy herds.

Short communication: Screening stable flies and house flies as potential vectors of digital dermatitis in dairy cattle.

Digital dermatitis is a bacterial infection that causes lesions above the heel bulbs on cattle hooves, and several bacterial species from the genus Treponema are suspected to be causative agents of this polymicrobial condition. Transmission of the bacteria to healthy cows is understudied, particularly with regard to potential insect vectors. Therefore, the objective of this research was to determine if flies captured from a dairy farm known to have digital dermatitis are contaminated with Treponema bacteria. The DNA-based assays did not detect any Treponema phagedenis from stable flies and house flies collected at a dairy experiencing an outbreak of digital dermatitis. Other potential means of bacterial transmission are discussed.

Short communication: Informative value of an ELISA applied to bulk tank milk to assess within-herd prevalence of digital dermatitis in dairy herds.

The objective of this study was to assess whether an antibody ELISA applied to bulk tank milk (BTM) could be used to accurately estimate within-herd prevalence of digital dermatitis (DD). The ELISA was designed for the detection of antibodies against Treponema phagedenis-like strain V1 (PrrA antigen). The hind feet of all lactating cows from 40 commercial French dairy herds with a history of DD were scored by an observer in the milking parlor, using the 4 M-stage system. After milking, a BTM sample was collected and tested for anti-Treponema phagedenis-like antibodies using the antibody ELISA. Within-herd DD prevalence at the cow level was determined using 2 different approaches: (1) having DD lesion on at least 1 hind foot (Prev; prevalence of affected cows), and (2) having an M1 or M2 lesion on at least 1 hind foot (PrevA; prevalence of cows affected by DD in an active stage). Receiver operating characteristic analysis was used to determine both optimal within-herd DD prevalence and BTM sample to positive (S/P) ratio cut-off values. Two optimal cut-off values were identified. Herds with an S/P ratio of BTM ≤0.2 had a Prev ≤10% (sensitivity = 0.97, specificity = 1), whereas herds with an S/P ratio of BTM >0.38 had a Prev >40% (sensitivity = 0.94, specificity = 0.86). In the same way but with a slightly lower specificity, an S/P ratio >0.38 corresponds also to a PrevA >18% (sensitivity = 0.92, specificity = 0.70). The BTM antibody ELISA shows great promise for screening purposes during DD management programs.

An observational study on the management of digital dermatitis through a repeated risk assessment on 19 Dutch dairy herds.

The etiopathogenesis of bovine digital dermatitis (DD) is not well understood, but its risk factors on dairy farms have been studied extensively. The objective of this study was to identify associations between a DD risk score [determined by a DD risk assessment questionnaire (RAQ)] and DD prevalence (determined by an in-parlor M-score). We also investigated whether feedback for farmers on their DD management using the DD RAQ resulted in changes that decreased DD prevalence in their herds. The DD RAQ consisted of multiple-choice questions related to foot health, housing, and general management that were used to create a total risk score (TRS). In 2016 and 2018, the DD RAQ-together with a DD prevalence determination in the lactating herd-was used on 19 Dutch dairy farms from 1 veterinary practice. After each visit, farmers and their consulting veterinarians received a 1-page summary that identified herd-specific strengths and weaknesses in DD management. In 2018, the summary included suggestions for improvement. In 2019, farmers and veterinarians were contacted to ask whether the use of the DD RAQ and the 1-page summary had led them to implement changes in their DD management in 2016 and 2018. We tested the association between TRS and DD prevalence using linear mixed model analysis. The TRS ranged from 13 to 65% and 20 to 68% in 2016 and 2018, respectively. Herd DD prevalence ranged from 15 to 59% and 27 to 69% in 2016 and 2018, respectively. For both years, the DD RAQ identified that DIM, herd size, and breed were often present in a manner associated with increased risk for DD. The linear mixed model analysis identified that each 10-point increase in TRS was associated with an increase in herd DD prevalence of less than 1%. The association between TRS and herd DD prevalence was caused mainly by risk factors related to housing. We found no important relationship between change in TRS and change in DD prevalence between the 2 visits. Only a few farmers indicated some form of change in their DD management following a visit. Veterinarians in general said that they discussed the 1-page summaries and DD control with farmers during a routine visit, but the majority admitted a lack of follow-up. We propose that the DD RAQ could be used as a tool to start a discussion on DD control on farm, but simply undertaking a DD RAQ and providing a 1-page summary of the results was insufficient to initiate behavioral change that led to a decrease in DD prevalence.

Foot health and prevalence of Dichelobacter nodosus in 11 ungulate species at Berne Animal Park.

INTRODUCTION: Dichelobacter nodosus (D. nodosus) is the etiological agent of ovine footrot affecting mainly sheep worldwide, but also free-ranging wild ungulates such as Alpine ibex (Capra ibex ibex) and mufflon (Ovis orientalis orientalis). A nationwide ovine footrot eradication program is planned for the years to come, based on polymerase chain reaction (PCR)-testing of interdigital swab samples and regular footbathing. In this cross-sectional study, we clinically evaluated the foot health and analysed presence of D. nodosus in 11 different even-toed ungulate species (mainly European species) during a 13 months (2018-2019) period in Berne Animal Park. The foot lesions were scored for any clinical signs of pathologies as described in cattle and simultaneously for clinical signs of footrot as described for sheep, using a scale from 0 to 5 (while 0 describes clinically healthy feet and 5 loss of the horn capsule). From a total of 53 animals, 4-feet swab samples were taken from the interdigital cleft and subjected to real-time PCR assays to detect D. nodosus at animal level. Foot lesions were detected in five different species. In 3/5 muskoxen (Ovibos moschatus wardi), 7/12 Cretan wild goats (Capra hircus cretica) and 2/3 dwarf goats (Capra hircus aegagrus), they mainly consisted of white line disease, whereas in 9/10 European bison, dermatitis of the interdigital cleft was diagnosed. 1/3 alpaca was diagnosed with chorioptic mange of the heel area. None of the examined animals showed clinical signs of footrot (score 0), and neither benign (aprB2-positive) nor virulent (aprV2-positive) D. nodosus were detected in any of the samples. This study provides additional information to facilitate an efficient ovine footrot control program in Switzerland and suggests that captive wild even-toed ungulates do not pose a risk to the planned footrot control program.

INTRODUCTION: Dichelobacter nodosus (D. nodosus) est l'agent étiologique du piétin chez les ruminants, qui affecte principalement les moutons dans le monde, mais aussi les ongulés sauvages en liberté tels que les bouquetins (Capra ibex ibex) et les mouflons (Ovis orientalis orientalis). Un programme d'éradication du piétin ovin à l'échelle Nationale, basé sur des tests PCR (réaction de polymérisation en chaîne) d'écouvillons de l'espace interdigité et des pédiluves réguliers, est prévu dans les années à venir en Suisse. Dans cette étude transversale, nous avons évalué cliniquement la santé des onglons et recherché la présence de D. nodosus chez 11 espèces différentes d'animaux biongulés (principalement des espèces européennes) pendant une période de 13 mois (2018­2019) au Parc animalier de Berne. Les lésions des onglons ont été notées pour tout signe clinique de pathologie et de présence de piétin, comme cela est décrit chez les bovins et les moutons et en utilisant une échelle de 0 à 5 (où 0 décrit des pieds cliniquement sains et 5 la perte de la boîte cornée). Des écouvillons ont été prélevés dans l'espace interdigité des 4 pieds sur un total de 53 animaux et soumis à des tests PCR en temps réel pour détecter D. nodosus. Des lésions aux onglons ont été détectées chez cinq espèces différentes. Chez 3 boeufs musqués (Ovibos moschatus wardi) sur 5, 7 chèvres sauvages crétoises (Capra hircus cretica) sur 12 et 2 chèvres naines (Capra hircus aegagrus) sur 3, il s'agissait principalement de lésions de la ligne blanche, alors que dans 9 bisons sur 10, le diagnostic était une dermatite interdigitale. Un alpaga sur 3 a été diagnostiqué avec une gale chorioptique de la zone du paturon. Aucun des animaux examinés n'a montré de signes cliniques de piétin (score 0) et aucun D. nodosus bénin (aprB2-positif) ou virulent (aprV2-positif ) n'a été mis en évidence dans les échantillons. Cette étude fournit des informations supplémentaires pour améliorer l'efficacité du programme d'éradication du piétin ovin et suggère que les biongulés sauvages détenus dans les parcs zoologiques ne présentent pas de risque pour le programme d'éradication prévu en Suisse.

Prevalence of foot lesions in Québec dairy herds from 2015 to 2018.

Our first objective was to estimate the prevalence of foot lesions by type of milking system in dairy cows examined during regular hoof-trimming sessions between 2015 and 2018 in Québec dairy herds. A secondary objective was to describe the effect of day-to-day variation, cow, and herd characteristics on the prevalence of foot lesions. Data included 52,427 observations (on a cow during a specific trimming session) performed on 28,470 cows (≥2 yr old) from 355 herds. Only observations from trimming sessions in which ≥90% of the lactating herd was trimmed were considered. Lesions were recorded at the hoof level by 17 trained hoof trimmers between March 23, 2015, and July 10, 2018, using a computerized recording system. Hoof-level information was then matched with cow information and centralized at the Eastern Canada Dairy Herd Improvement. Foot lesions were classified into 6 categories: infectious, white line disease, heel erosion, ulcers, hemorrhages, and any type of foot lesions. Prevalence of each outcome was quantified using the marginal predicted mean probability estimated from a null generalized linear mixed model with a logit link, and accounted for clustering of observations by cow and by herd. Variance was partitioned to assess the variation in the probability of the outcomes attributable to each level of the data structure (day of exam, cow, and herd). Prevalence of a given foot lesion as function of milking system and of various explanatory variables (mean herd size, herd average daily production, breed of the cow, age of the cow at trimming, and year of the visit) was then estimated using a generalized linear mixed model. At least 1 foot lesion was observed in 29% of cows examined during regular trimming sessions in Québec from 2015 to 2018. Prevalence for any type of lesion was 27% for pipeline, 38% for robotic milking, and 41% for milking parlors. The highest prevalence of infectious lesions (mainly digital dermatitis) was observed in milking parlors and robotic systems, while the most prevalent lesions in pipeline were hemorrhages. Herd-level factors explained most of the disease probability for infectious diseases, heel erosion, and hemorrhages. Therefore, control of these diseases should be based on applying best herd-management practices. On the other hand, probabilities of white line disease and sole ulcers were mainly determined by cow-level characteristics.

Hot topic: Detecting digital dermatitis with computer vision.

Digital dermatitis (DD) is linked to severe lameness, infertility, and decreased milk production in cattle. Early detection of DD provides an improved prognosis for treatment and recovery; however, this is extremely challenging on commercial dairy farms. Computer vision (COMV) models can help facilitate early DD detection on commercial dairy farms. The aim of this study was to develop and implement a novel COMV tool to identify DD lesions on a commercial dairy farm. Using a database of more than 3,500 DD lesion images, a model was trained using the YOLOv2 architecture to detect the M-stages of DD. The YOLOv2 COMV model detected DD with an accuracy of 71%, and the agreement was quantified as "moderate" by Cohen's kappa when compared with a human evaluator for the internal validation. In the external validation, the YOLOv2 COMV model detected DD with an accuracy of 88% and agreement was quantified as "fair" by Cohen's kappa. Implementation of COMV tools for DD detection provides an opportunity to identify cows for DD treatment, which has the potential to lower DD prevalence and improve animal welfare on commercial dairy farms.

Detection of Treponema spp. in bovine digital dermatitis in the Amazon biome, Brazil / Detecção de Treponema spp. em dermatite digital bovina no bioma amazônico, Brasil

Bovine digital dermatitis (BDD) is a polybacterial claw disease that is endemic to dairy cattle kept in loose house systems, and treponemas are the main bacteria implicated in this disease. The objective of this study was to report the occurrence of Treponema spp. in BDD from crossbred dairy cattle (Holstein x Zebu) kept in a pasture in the Brazilian Amazon biome. The diagnostic of BDD was performed by inspecting the distal extremities of cattle during milking in one or more visits comprising 15 farms. In total, it could be inspected 1,847 cows from August 2016 to July 2017, and 25 lesions of BDD were diagnosed. The feet were scored (System M: M0 = no lesion, M1 = ulcer stage <2cm, M2 = ulcer stage >2cm, M3 = healing stage, M4 = chronic stage, M4.1 = chronic stage with ulcer area). Twenty four biopsy samples were taken from feet with BDD and five biopsy samples from feet with no lesions. The histopathology of stained tissues was performed by hematoxylin and eosin and Warthin-Starry method. The samples were also tested by nested PCR for the three previously isolated BDD Treponema phylogroups (T. medium/T. vincentii-like, T. phagedenis-like and T. putidum/T. denticola-like). Spirochetes were observed in 54.2% (13/24) of the lesions, and in 91.7% (22/24) of the samples were detected the DNA of this spirochete belonging to the treponema phylogroups implicated in BDD. In 25% (6/24) of the lesions were detected all the phylogroups. Forty percent (40%, 2/5) of the M0 samples were also positive for the nested Polymerase Chain Reaction (nested-PCR), as 8.3% (2/24) of the lesions were negative in both techniques employed. Treponema putidum/T. denticola-like was the most detected bacterial in all the stages, and active lesions (M2 and M4.1) presented a greater proportion of T. medium/T. vincentii-like and T. phagedenis-like, but no statistical differences were observed (p>0.05). It could be concluded that BDD lesions in crossbred dairy cattle kept to pasture in the Amazon biome were classified as "polytreponemal" infections and the phylogroup T. putidum/T. denticola-like was the most frequent in the lesions.(AU)

Dermatite digital bovina (DDB) é uma enfermidade polibacteriana dos dígitos endêmica em vacas leiteiras criadas em estábulos e as treponemas são as principais bactérias envolvidas. Este estudo teve como objetivo relatar a ocorrência de Treponema spp. em DDB em bovinos leiteiros mestiços (Holandês x Zebu) criados a pasto no bioma amazônico brasileiro. O diagnóstico da DDB foi realizado pela inspeção, em uma ou mais visitas, das extremidades distais das vacas durante a ordenha em 15 propriedades. No total, foram inspecionadas 1.847 vacas de agosto de 2016 a julho de 2017 e diagnosticou-se 25 lesões de DDB. As extremidades distais inspecionadas foram classificadas em escores (M0 = sem lesão, M1 = estágio ulcerado <2cm, M2 = estágio ulcerado >2cm, M3 = estágio em cicatrização, M4 = estágio crônico, M4.1 = estágio crônico com área ulcerada) e realizada 24 biópsias de dígitos com DDB e cinco biópsias de dígitos em estágio M0. Foram realizadas a histopatologia pelas colorações de hematoxilina e eosina e pelo método de Warthin-Starry, e a nested de reação em cadeia de polimerase (nested-PCR) para os três filogrupos de treponemas previamente isolados de DDB (Treponema medium/T. vincentii-like, T. phagedenis-like e T. putidum/T. denticola-like). Espiroquetas foram observadas em 54,2% (13/24) das lesões e em 91,7% (22/24) detectou-se o DNA de, pelo menos, um dos filogrupos de treponemas pesquisados. Em 25% (6/24) das lesões foram detectados o DNA dos três filogrupos. Em 40% (2/5) das amostras em estágio M0 também foram positivas na nested-PCR, assim como 8,3% (2/24) das lesões foram negativas em ambas as técnicas empregadas. T. putidum/T. denticola-like foi o filogrupo mais detectado em todos os estágios e lesões ativas (M2 e M4.1) apresentaram uma maior proporção para Treponema medium/T. vincentii-like e T. phagedenis-like, mas não se obteve diferença estatística na ocorrência dos filogrupos entre os estágios das lesões (P>0,05). Conclui-se que lesões de DDB em rebanhos leiteiros mestiços criados a pasto no bioma amazônico brasileiro são "politreponemais" e o filogrupo T. putidum/T. denticola-like é o mais frequente nas lesões.(AU)