Effectiveness of different regimens of a collective topical treatment using a solution of copper and zinc chelates in the cure of digital dermatitis in dairy farms under field conditions

Association between a genetic index for digital dermatitis resistance and the presence of digital dermatitis, heel horn erosion, and interdigital hyperplasia in Holstein cows

Digital dermatitis (DD) is a polybacterial disease endemic to most UK dairy farms. It poses a major financial and welfare threat and is characterized by high incidence and recurrence rates. We aimed to investigate the association between the UK EBV for resistance to digital dermatitis, the digital dermatitis index (DDI), and the frequency of DD, heel horn erosion (HHE), and interdigital hyperplasia (IH) in a population of Holstein dairy cows. We enrolled and genotyped 2,352 cows from 4 farms in a prospective cohort study. Foot lesion records were recorded by veterinary surgeons for each animal at 4 time points during a production cycle, starting at approximately 2 mo before calving and ending in late lactation. Importantly, these records were not used in the calculation of the DDI. Lesion records were matched to the animal's own DDI (n = 2,101) and their sire's DDI (n = 1,812). Digital dermatitis index values in our study population ranged from -1.41 to +1.2 and were transformed to represent distance from the mean expressed in SD. The relationship between the DDI and the presence of DD was investigated using a logistic regression model, with farm, parity, and a farm-parity interaction fitted as covariates. A multivariable logistic regression model was fitted to evaluate the relationship between HHE and DDI with farm fitted as a covariate. Finally, a univariable logistic regression model with DDI as explanatory variable was used to investigate the relationship between IH and DDI. The odds ratio of an animal being affected by DD was 0.69 for 1 SD increase in the animal's DDI (95% CI = 0.63-0.76). The odds of HHE and IH were 0.69 (95% CI = 0.62-0.76) and 0.58 (95% CI = 0.49-0.68) respectively for 1 SD increase in DDI. The adjusted probability of DD was 32% (95% CI = 27-36%) for cows with mean DDI value of 0, while it was 24% (95% CI = 20-29%) in cows with a DDI value of +1. Sire DDI breeding values were standardized in the same way and then binned into terciles creating an ordinal variable representing bulls of high, medium, and low genetic merit for DD resistance. The daughters of low genetic merit bulls were at 2.05 (95% CI = 1.60-2.64), 1.96 (95% CI = 1.53-2.50), and 2.85 (95% CI = 1.64-5.16) times greater odds of being affected by DD, HHE, and IH, respectively, compared with the daughters of high genetic merit bulls. The results of this study highlight the potential of digital dermatitis genetic indexes to aid herd management of DD, and suggest that breeding for resistance to DD, alongside environmental and management control practices, could reduce the prevalence of the 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.

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.

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

BACKGROUND

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.

HYPOTHESIS/OBJECTIVES

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.

ANIMALS

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.

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSION AND CLINICAL RELEVANCE

Over a 15 week period, QASD for footbathing was associated with a lower prevalence of active DD lesions than when using CZS.

Variations in the Physical Properties and Microbial Community of Dairy Cow Manure-Implications for Testing and Efficacy of Footbathing Products

Footbaths containing disinfectants are used on dairy farms to reduce the spread of digital dermatitis; however, they commonly become contaminated with manure. This trial investigated the physical properties and microbial composition of dairy cow manure from two production systems and examined whether the source of manure impacted the efficacy of footbathing disinfectants. Manure was collected from eighteen dairy cows, nine housed and fed grass silage (HOUSED) and nine at pasture (PASTURE). The pH and dry matter content was determined, total DNA was extracted and the region v3-v4 of the 16s rRNA gene sequenced. The efficacy of formalin and two trial products (TP1: peracetic acid and hydrogen peroxide; TP2: chlorocresol and triamine) was evaluated when mixed with manure from the two production systems. Production system differences were found in manure dry matter content, bacterial microbiome and the efficacy of both trial footbathing products but not formalin. The properties of manure affected the results of laboratory testing and therefore have the potential to influence footbathing disinfectant efficacy when footbaths are contaminated with manure. Further research into the impact of organic contaminants on the efficacy of disinfectants could facilitate the development of improved testing programmes and disinfectant products.

Management of Digital Dermatitis in Dairy Herds: Optimization and Time Allocation

The objective of this study is to determine the most effective time allocation for digital dermatitis management and to quantify the marginal economic gain from extra time devoted to digital dermatitis management. The model simulating foot disease occurrence and the associated management was Dairy Health Simulator©. Then, an econometric model was applied to identify the relationship between the dairy workshop's gross margin and time for lameness management as well as the hourly marginal gain curve associated with lameness management. The gross margin was optimized under two constraints, i.e., the overall time spent for lameness management and the mean lameness duration (mimicking cow welfare). The results show that allocating less time to lameness detection and more to footbath application can contribute as follows: (i) reduces time spent for lameness management, (ii) maintains the best welfare level, and (iii) obtains the highest gross margin. The optimal time to devote to footbath application ranged from 17.8 to 22.3 h/month. A hiring strategy was investigated, and the break-even point ranged from 16.1 to 19.8 h/month. The recommended time to spend on footbath application is relatively important; therefore, stakeholders should consider the importance of lameness to the dairy industry and should devote enough time for footbath applications.

Cost of lameness in dairy herds: An integrated bioeconomic modeling approach

Foot disorders are costly health disorders in dairy farms, and their prevalence is related to several factors such as breed, nutrition, and farmer's management strategy. Very few modeling approaches have considered the dynamics of foot disorders and their interaction with farm management strategies within a holistic farm simulation model. The aim of this study was to estimate the cost of foot disorders in dairy herds by simulating strategies for managing lameness. A dynamic and stochastic simulation model (DairyHealthSim) was used to simulate the herd dynamics, reproduction management, and health events. A specific module was built for lameness and related herd-level management strategies. Foot disorder occurrences were simulated with a base risk for each etiology [digital dermatitis (DD), interdigital dermatitis, interdigital phlegmon, sole ulcer (SU), white line disease (WLD)]. Two state machines were implemented in the model: the first was related to the disease-induced lameness score (from 1 to 5), and the second concerned DD-state transitions. A total of 880 simulations were run to represent the combination of the following 5 scenarios: (1) housing (concrete vs. textured), (2) hygiene (2 different scraping frequencies), (3) the existence of preventive trimming, (4) different thresholds of DD prevalence detected and from which a collective footbath is applied to treat DD, and (5) farmer's ability to detect lameness (detection rate). Housing, hygiene, and trimming scenarios were associated with risk factors applied for each foot disorder etiologies. The footbath and lameness detection scenarios both determined the treatment setup and the policy of herd observance. The economic evaluation outcome was the gross margin per year. A linear regression model was run to estimate the cost per lame cow (lameness score ≥3), per case of DD and per week of a cow's medium lameness duration. The bioeconomic model reproduced a lameness prevalence varying from 26 to 98% depending on the management scenario, demonstrating a high capacity of the model to represent the diversity of the field situations. Digital dermatitis represented half of the total lameness cases, followed by interdigital dermatitis (28%), SU (19%), WLD (13%), and interdigital phlegmon (4%). The housing scenarios dramatically influenced the prevalence of SU and WLD, whereas scraping frequency and threshold for footbath application mainly determined the presence of DD. Interestingly, the results showed that preventive trimming allowed a better reduction in lameness prevalence than spending time on early detection. Scraping frequency was highly associated with DD occurrence, especially with a textured floor. The regression showed that costs were homogeneous (i.e., did not change with lameness prevalence; marginal cost equals average cost). A lame cow and a DD-affected cow cost €307.50 ± 8.40 (SD) and €391.80 ± 10.0 per year on average, respectively. The results also showed a cost of €12.10 ± 0.36 per week-cow lameness. The present estimation is the first to account for interactions between etiologies and for the complex DD dynamics with all the M-stage transitions, bringing a high level of accuracy to the results.

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.

Proof of an optimized salicylic acid paste-based treatment concept of ulcerative M2-stage digital dermatitis lesions in 21 dairy cows

The efficacy of salicylic acid paste (SA) in the treatment of ulcerative bovine digital dermatitis (BDD) was assessed by combining clinical and histopathological analyses with molecular biological techniques. The latter were conducted in a blinded manner to reach maximum objectivity. Prior to treatment, M2-stage BDD lesions (n = 26, diagnosed in 21 dairy cows) exhibited ulceration, with severe perivascular, chronic, lymphoplasmacytic dermatitis and extensive keratinolysis being noted in most cases. Pretreatment biopsy samples (n = 12) followed by povidone-iodine ointment under bandage for one week before administration of SA paste were tested positive for Treponema spp. by blinded PCR and fluorescent in situ hybridization (FISH). Subsequent treatment consisted of application of SA and bandaging at weekly intervals until lesions had completely resolved. The treatment duration ranged between 2 and 4 weeks. Complete healing was achieved in 100% of cases, with 2/21 animals requiring a second round of treatment upon disease reoccurrence. Importantly, only 3/26 biopsies taken from previously affected sites still tested positive by Treponema PCR, and in another biopsy, the outermost layers of the stratum corneum scored weakly positive by Treponema-specific FISH. None of these Treponema DNA-positive biopsies showed signs of ulceration. One case exhibited focal keratinolysis. Positive PCR or FISH in these cases may have arisen from DNA traces of dead bacteria or environmental contamination during biopsy harvesting. To our knowledge, this is the first study on blinded molecular biological monitoring of the therapeutic efficacy of SA with respect to treponemal infection, and on complete BDD M2-stage remission in all animals achieved by SA treatment according to an optimized protocol. Although the etiology of BDD is considered as multifactorial, our data further support the concept that treponemes have a decisive role in BDD pathogenesis.

A proposed structural approach to improve cow-claw health on Dutch dairy farms

Despite extensive research leading to an improved understanding of the risk factors and pathogenesis of infectious and non-infectious disorders, claw health has not structurally improved in recent decades. Several studies have shown that claw disorders harm milk production, fertility and longevity of the dairy cows and job satisfaction of the farmer. This is enough reason to structurally improve claw health on dairy farms. The focus should be on a rapid curative intervention when lameness occurs and above all the prevention of claw problems. Most claw disorder diagnoses are nowadays made during regular claw trimming by the professional trimmer or the dairy farmer. Registration of the detected disorders during claw trimming is not always done consistently, so the estimated prevalence (number of cows with a claw disorder) is in most cases an underestimation of the real prevalence. The quality of these records often makes it difficult for consultants to formulate appropriate claw health advice. To be able to give good advice on claw health, insight into the prevalence of the various hoof disorders on a farm is a key condition. However, good quality advice alone is not a guarantee for an improved claw health situation on a farm. Research has shown that in addition to high quality substantiated advice, the communication style between the consultant and the dairy farmer is essential for the interpretation and motivation of the dairy farmer to implement the advice. In this paper a 7-point plan is presented as a guidance for herd advisors who want to support dairy farmers to improve claw health.

Risk factors for digital dermatitis in free-stall-housed, Canadian dairy cattle

BACKGROUND

A comprehensive analysis of the relation between digital dermatitis (DD) and cow and herd characteristics in Canadian dairies is currently lacking.

METHODS

A multilevel logistic regression analysis was performed using 12,260 cow records from 62 dairy farms to assess association between 27 cow and herd-level variables, and presence of DD.

RESULTS

The odds for a cow to have at least 1 DD lesion were higher in first-parity cows and those in later lactation (≥45 days in milk). Housing cows on a concrete base was associated with higher odds (OR 2.24) for DD when bedding was added once a week or less. Bedding the concrete base more frequently reduced odds for DD. Wood shavings or other bedding types were more positively associated with DD (OR 2.31 and 1.87, respectively) compared to sawdust. Also, the odds of DD were lower on farms with a scraping manure frequency of every 2 h compared to less frequent scraping (OR 0.54).

CONCLUSION

Nine risk factors for DD were identified and quantified, with stall base, bedding type, and manure scraping frequency associated with lower odds of DD. DD prevalence could be reduced by implementing management practices for first-parity cows, as they had higher odds of DD.

Phenytoin: A promising non-antibiotic drug for the topical treatment of digital dermatitis in dairy cows

Background and Aim:

Digital dermatitis (DD) is one of the most common causes of lameness in dairy cattle. It is seen in nearly all dairy herds across the world and has substantial welfare and economic implications. In this study, we aimed to investigate the efficacy of phenytoin sodium topical treatment on painful ulcerative stage of bovine digital dermatitis (BDD).

Materials and Methods:

In total, 45 Holstein-Friesian dairy cows with DD were randomly assigned to one of the three topical treatment trials (15 each): Saline solution (first treatment, negative control), chlortetracycline spray (second treatment, positive control), or phenytoin sodium powder (third treatment, positive control) (third treatment). On day 0 (pre-treatment) and on days 7, 14, 21, and 28 post-treatment, the response of DD-affected cows to the medications used was evaluated by measuring lesion depth and size, as well as the total clinical score (lameness, pain, and discomfort).

Results:

The cure rate in cows treated with phenytoin (86.66%) on day 28 was significantly improved compared to cows treated with either chlortetracycline (60%) or normal saline (6.66 %).

Conclusion:

Our findings highlight the superiority of phenytoin over the commonly used antibacterial agent, chlortetracycline, in the topical treatment of BDD, and subsequently suggest that phenytoin should be considered a suitable alternative treatment option for the treatment of BDD.

Recovery from udder cleft dermatitis in dairy cows

Udder cleft dermatitis (UCD) is a common skin problem in dairy cows, localized at the fore udder attachment or between the udder halves. The main objectives of this study were to investigate spontaneous recovery from UCD in a longitudinal study and to investigate the treatment effect on UCD of a topical spray containing chelated copper and zinc in an additional treatment trial. Spontaneous recovery was investigated during a 1-yr longitudinal study in which 7 Swedish dairy herds were visited 9 times each, at 6-wk intervals. During the visits, all cows milked in the milking parlor were examined for mild and severe UCD, udder conformation traits, hygiene, and hock lesions. Additional cow and herd data were obtained from the Swedish official milk recording scheme. Recovery was defined as 2 consecutive observations of no UCD after a UCD case (1 or more consecutive observations of UCD). The recovery rate was calculated and factors associated with recovery were analyzed using discrete-time survival analysis. A treatment study was conducted in 4 of the herds after completion of the longitudinal study. Cows with UCD were allocated to treatment or a control group, and cows in the treatment group were treated once every day for 14 to 28 d. At follow-up visits on d 14, 28, and 56, all cows were scored for UCD. To investigate the effect of treatment, an ordered logistic regression model was used, with UCD score on d 56 (no, mild, or severe) as the outcome. Other potential explanatory variables were also included in the model. A total of 38% (126 of 329) of the cows in the longitudinal study made a spontaneous recovery from UCD. A long duration of UCD, severe lesions and higher parity reduced the chance of recovery. Among the recovered cows, 47% (59 of 126 cows) had a recurrent case of UCD after the recovery. In the treatment study, there was no difference in UCD score on d 56 between the treatment and control groups. Factors that affected the UCD score on d 56 were the duration of UCD before the treatment study started, UCD score on d 1 and udder conformation. Our findings emphasize the importance of further studies to identify effective treatment regimens as well as further studies to unravel the pathophysiology of UCD to improve the recommendations on how to prevent these lesions.

Risk factors associated with lameness and hoof lesions in pasture-based dairy cattle systems in southeast Brazil

Cattle lameness is an important welfare concern that also has an economic impact on the dairy industry. It can be a significant problem among pasture-based herds. Our objectives were to identify cow- and herd-level factors related to lameness and hoof lesions in dairy cows grazing year-round in Minas Gerais, Brazil. We performed a cross-sectional study in 48 pasture-based dairy herds, visiting each farm in a single visit. We evaluated 2,262 cows for mobility score (0-3) and 392 cows for hoof lesions. We used a questionnaire and checklist to capture herd management data. All information obtained was used to build multivariable models. The factors associated with lameness were low body condition score, longer time spent in the corral, being kept in paddocks during the drought period, and poor hygiene. For hoof lesions, track features were the most significant factor in determining the likelihood of heel horn erosion, white line fissure, and sole hemorrhage-by more than 3 times. Different factors related to unhygienic conditions such as leg cleanliness, frequency of cleaning, and longer time spent in the corral were associated with infectious hoof lesions. Poor human-animal relationship was related to sole hemorrhage, but patient handling of cows on the track was a protective factor against interdigital hyperplasia. The results of this study suggest that improving hygiene conditions, track features, and cow handling can improve dairy cattle mobility scores in pasture-based farms under tropical conditions. These findings also represent a first step toward planning actions aimed at decreasing lameness and hoof lesions in the studied region.

Randomised clinical trial showing the curative effect of bandaging on M2-stage lesions of digital dermatitis in dairy cows

Objectives and design

This trial evaluated the effect of bandaging of acute painful ulcerative bovine digital dermatitis (DD) lesion (stage M2) in dairy cows, tested using two different topical treatments.

Design

Randomised clinical trial.

Setting

This study was conducted using Holstein-Friesian cows ranging in age from heifers to fourth lactation in a single dairy herd and diagnosed with acute ulcerative DD lesions (stage M2) on the first examination (week 0). Cows were randomly assigned into either a non-bandaged or bandaged group across two treatment conditions: topical chlortetracycline spray (CTC) and Intra Hoof-Fit Gel (IHF). Lesions received standardised bandaging and treatment on a weekly basis. Unhealed lesions could receive up to five repeated treatments, at weekly intervals, within a four-week period. Both M-stage and locomotion were also evaluated and scored weekly. Cows with healthily formed skin (stage M0) were deemed healed and subsequently released from the study.

Results

In total, 163 M2 lesions were diagnosed at week 0. Bandaged M2 lesions had a significantly higher probability of cure than non-bandaged lesions regardless of treatment type (HR: 4.1; P<0.001; 95 per cent CI: 2.5 to 6.8). Most healing occurred within the first three weeks of trial. Furthermore, bandaged lesions (group 2 and group 4) were significantly less likely to progress into the chronic hyperkeratotic or proliferative stage (M4) than non-bandaged lesions in group 1 and group 3 (HR: 0.10; P<0.001; 95 per cent CI: 0.04 to 0.22). Out of concern for the cow’s wellbeing, this study investigated the effects of bandaging on locomotion. Bandaging had no effect on locomotion for either cows treated with CTC (group 1: median Sprecher score, 2; IQR=1–2; group 2: median Sprecher score, 2; IQR=1–3; P=0.3) or IHF (group 3: median Sprecher score, 2; IQR=1–2; group 4: median Sprecher score, 2; IQR=1–3; P=0.3).

Evaluation of a biocide footbath solution in the occurrence and healing of digital dermatitis lesions in dairy cows: A clinical trial

The objective of this study was to evaluate the effect of the implementation of different footbathing practices using a new biocide solution (Pink-Step™, Qalian, France) in the healing and the occurrence of bovine digital dermatitis (bDD) lesions. The investigation was conducted through a controlled within cow clinical trial in which the hind feet of cows from each farm were allocated either to the control group or to a moderate (MR) or (IR) intensive footbath-regimen groups. The trial involved 1036 cows (2072 feet) from 10 dairy farms located in western France where bDD was endemic. Split-footbaths were placed at the exit of the milking parlor of each farm, allowing the biocide to be administered to one side of the cows while using the other empty side as a negative control. The administration frequency for MR was of 2 days/week/1st-month, then 2 days/2 weeks/2nd-month, and then 2 days/month, and for IR was of 2 days/week/1st-2nd months, and then 2 days/2 weeks. Footbaths were administered during 140 days (approx.), and feet were evaluated for the at least once a month in the milking parlor. Nested survival models were used to estimate the relative impact of the footbath regimens and other concomitant risk factors on the time that bDD lesions occurred or healed. No effect of Pink-Step™ was evidenced on the bDD occurrence during the trial. The risk for bDD occurrence was increased by poor feet cleanliness at both the cow (HR 1.69, CI 1.21-2.39) and farm level (HR 2.06, CI 1.44-2.94). Otherwise, the use of Pink-Step™ in an IR was effective in improving the healing of bDD lesions (HR 1.79, CI 1.12-2.88). The time to healing was also improved in inactive lesions (HR 2.19, CI 1.42-3.37). Conversely, the time to healing was delayed in feet receiving hoof-trimming (HR 0.41, CI 0.26-0.62), in cows with a contralateral bDD lesion (HR 0.32, CI 0.22-0.46) or in late lactation (HR 0.61, CI 0.43-0.85), and finally in farms with more than 100 cows (HR 0.48, CI 0.34-0.67). These findings reinforce the crucial role of hygiene in bDD dynamics and highlight the importance of implementing multiple control measures simultaneously, such as hygiene improvements in the barn, early detection and treatment of bDD lesions and the correct usage of individual and collective treatments. The implementation of Pink-Step™ represents a promising strategy for reducing the persistence of bDD lesions in affected herds.

Effect of footbath protocols for prevention and treatment of digital dermatitis in dairy cattle: A systematic review and network meta-analysis

Digital dermatitis (DD) is an infectious bacterial disease affecting cattle feet. Footbaths are a common herd-level control method for DD; however, variations in product, concentration, and frequency of use complicate comparisons between protocols. The objective of this systematic review was to evaluate all walk-through footbath protocols reported that determined efficacy for prevention and treatment of DD lesions in dairy cattle. An extensive literature search was conducted, including electronic databases and gray literature updated until March 2018. Studies identified included all liquid walk-through footbath protocols that were compared to other footbath protocols or no footbath. Only studies with treatment or prevention of DD lesions as an outcome were included. Literature search and subsequent screening identified 14 publications with 24 treatment comparisons and 24 prevention comparisons. Studies included mostly had low and/or unclear risks of bias. Descriptive analyses were performed according to prevention and treatment outcomes, with case and success definitions summarized as odds ratios (OR). A subsequent network meta-analysis was conducted of 11 studies, comparing 17 protocol comparisons for the prevention outcome and 10 studies comparing 19 protocol comparisons for the treatment outcome, using semi-informative priors in a Bayesian statistical framework. Results of a random effects Bayesian network meta-analysis indicated only 5% copper sulfate used at least 4 times/wk was superior to both no footbath (OR: 5.26; 95% CrI: 1.27-28.8) and a water placebo (OR: 9.47; 95% CrI: 1.03-85.8) in treatment of DD. No other protocol was associated with a reduction in DD, and there were no differences in pair-wise comparisons between any active treatments. Unfortunately, for both outcomes (treatment and prevention), small sample sizes (adjusted for clustering) limited the power to detect substantial differences between protocol effects. Thus, despite widespread use of footbaths, limited strength of evidence for use remains and standardized protocols with large sample sizes are needed to further investigate effectiveness of footbath protocols for control of DD. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Current recommendations for footbath solutions renewal rates in dairy cattle: the need for adaptation?

Footbaths represent a potentially useful strategy for the prevention of claw infectious diseases by treating a large number of animals concomitantly. Nevertheless, under field conditions, footbath solutions are exposed to increasing number of animal passages and therefore, to different volume losses and concentrations of manure contamination which could alter their presumed bactericidal activity. Across increasing number of cow passages, the organic matter (OM) concentration, the microbial load (ML) and the residual volumes were assessed in six commercial farms. The results indicate that the OM concentration and ML increased linearly with the number of passages of animals, and with the number of defecations in the footbath. The OM concentrations and the ML were not impacted by the farm's feet hygiene status (clean, fair and dirty), suggesting that probably the increasing number of cow passages and defecations influenced more the contamination of footbaths than the hygiene of the feet. In all the farms the volumes decreased drastically after 200 cow passages (50%). The OM concentrations after 150 and 200 cow passages did not exceed the regulatory concentrations in which disinfectant products should demonstrate to still be effective (20 g/l), and coincide with the often advised renewal rates. The findings of this study suggested that beyond the footbath contamination by OM, the renewal rates must be mainly adapted according to the remaining volume to guarantee that the entire foot is covered and therefore assure the topical action of the solution. This study highlights the importance of footbath designs for the successful implementation of these strategies in practice.

Comparison of effects of routine topical treatments in the milking parlor on digital dermatitis lesions

Digital dermatitis (DD), an infectious bacterial disease affecting the feet of dairy cattle, can cause lameness and decrease milk production, fertility, and animal welfare. Current DD treatment typically involves routine hoof trimming and topical antibiotics. Several nonantibiotic commercial topical products are used for controlling DD lesions; however, there is limited or no evidence regarding their effectiveness. The objectives of this study were to evaluate 2 commercially available topical applications on their ability to (1) clinically cure active DD lesions to nonactive lesions and (2) prevent recurrence of active DD lesions. Ten farms were visited weekly. In the milking parlor, the hind feet of lactating cattle were cleaned and scored (M-stage scoring system). Cattle with DD lesions at the first visit were randomly allocated to 1 of 4 treatment groups: positive control (tetracycline solution), HealMax (AgroChem Inc., Saratoga Springs, NY), HoofSol (Diamond Hoof Care Ltd., Intracare BV, Veghel, the Netherlands), and a negative control (saline). All products were applied to lesions using a spray bottle. Tetracycline, HealMax, and HoofSol had a higher probability of clinical cure for active lesions compared with saline 1 wk after the first treatment (wk 1), with 69, 52, and 79% clinical cure of active lesions, respectively, compared with 34% with saline. At wk 7, the probability of clinical cure for active lesions was 10, 33, 31, and 45% of lesions treated weekly with saline, tetracycline, HealMax, and HoofSol, respectively (no difference among treatments). The substantial clinical cure with saline highlighted the potential importance of cleaning feet. In wk 1, treatment with saline, tetracycline, HealMax, and HoofSol resulted in a probability of recurrence of active DD lesions of 9, 11, 11, and 8%, respectively, with no product being superior to saline. After 7 wk, the probability of recurrence of active lesions was 5, 7, 6, and 6% for saline, tetracycline, HealMax, and HoofSol respectively, with no difference among groups in wk 7. These results provide alternatives to antibiotics for treatment of DD lesions and highlight the potential importance of cleaning feet in the milking parlor.

Digital Dermatitis in dairy cattle: The contribution of different disease classes to transmission

Digital Dermatitis (DD) is a claw disease mainly affecting the hind feet of dairy cattle. Digital Dermatitis is an infectious disease, transmitted via the environment, where the infectious "agent" is a combination of bacteria. The standardized classification for DD lesions developed by Döpfer et al. (1997) and extended by Berry et al. (2012) has six distinct classes: healthy (M0), an active granulomatous area of 0-2 cm (M1), an ulcerative lesion of >2 cm (M2), an ulcerative lesion covered by a scab (M3), alteration of the skin (M4), and a combination of M4 and M1 (M4.1). We hypothesize that classes M1, M2, M3, M4, and M4.1 are the potentially infectious classes that can contribute to the basic reproduction ratio (R₀), the average number of new infections caused by a typical infected individual. Here, we determine differences in infectivity between the classes, the sojourn time in each of the classes, and the contribution of each class to R_0. The analysis is based on data from twelve farms in the Netherlands that were visited every two weeks, eleven times. We found that 93.89% of the transitions from M0 was observed as a transition to class M4, and feet with another class-at-infection rapidly transitioned to class M4. As a consequence, about 70% of the infectious time was spent in class M4. Transmission rate parameters of class-at-infection M1, M2, M3, and M4 were not significantly different from each other, but differed from class-at-infection M4.1. However, due to the relative large amount of time spend in class M4, regardless of the class-at-infection, R₀ was almost completely determined by this class. The R₀ was 2.36, to which class-at-infection M4 alone contributed 88.5%. Thus, M4 lesions should be prevented to lower R₀ to a value below one, while painful M2 lesions should be prevented for animal welfare reasons.

Early detection and treatment of lame cows

Objective: The aim of this study was to investigate the impact of specific hoof lesions on the locomotion score (LS) as well as the effect of early detection and treatment on duration and prevalence of lesion-specific lameness. Material and methods: In a dairy herd in Lower Saxony, Germany, with 144 lactating cows, claw trimming was performed by a professional claw trimmer at the beginning and the end of a 41-week trial period. Weekly a veterinarian assessed the LS according to Sprecher et al. (1997) in 99 cows. The front and hind claws of cows with an LS > 1 were examined and treated within 5 days. For individual diagnoses, the duration of lameness was calculated as the number of weeks from first treatment until recovery (LS = 1).Results: In total, 580 examinations and treatments were performed on 94 cows. There were 189 new lameness cases with a total of 290 diagnoses. At the first treatment, 81.0% of the cows displayed an LS of 2. Cows with digital dermatitis (DD), heel horn erosion and white line disease (WLD) more often had an LS > 2 compared to cows with Rusterholz’ sole ulcer, interdigital hyperplasia or inadequate claw length/posture (p < 0.05). Cows with only one affected leg, more often had an LS > 2 than cows with several affected legs (p < 0.1). Lameness caused by WLD and arthritis/ periarthritis remained for the longest time period. The prevalence of sole haemorrhages and/or double soles, WLD, interdigital dermatitis and interdigital hyperplasia decreased significantly during the test period. Prevalence of sole ulcer (sole ulcer and Rusterholz’ sole ulcer) and DD remained unaffected. Conclusion and clinical relevance: Locomotion score was affected by the type of claw/limb disorder and the number of diseased limbs. Regular locomotion scoring and continuous treatment of cows with an LS > 1 is associated with a decrease in the prevalence of several claw lesions. Therefore, prevalence of severe claw lesions like WLD, which was associated with a long duration of lameness, can be reduced. In con trast, for decreasing prevalence of digital dermatitis more than weekly treatment of every cow with LS > 1 is required. Preventive measures like footbaths or improved hygiene should accompany the individual animal treatment.

A clinical and histopathological comparison of the effectiveness of salicylic acid to a compound of inorganic acids for the treatment of digital dermatitis in cattle

Bovine digital dermatitis (DD) is a painful infectious disease, causing lameness, reduced animal welfare, and production losses in dairy herds. The main factors contributing to DD are an infection with Treponema spp. and poor hygiene. Topical treatment has primarily consisted of antibiotics; however, the demand for effective nonantibiotic alternatives is increasing. The objective was to evaluate the performance of 3 nonantibiotic topical treatments (salicylic acid and a compound of inorganic acids in a 20% solution and in a dry form) on DD in a commercial dairy herd. Within the 30-d test period, 42 DD lesions on 33 Holstein cows were assigned to receive 1 of the 3 treatments. Lesions were biopsied before and after treatment and were clinically evaluated 5 times. Improved lesions were clinically defined as either healed (regeneration of the skin) or healing (dry lesions covered by a scab). Unhealed lesions were defined as either active [with a raw, moist, strawberry-like (granulating) surface] or mature (with a raised papillomatous appearance). The effectiveness of treatment was evaluated histopathologically using the following scores: 0 (no spirochetes present), 1 (small number of spirochetes present in the epidermis), 2 (moderate number of spirochetes present and reaching an intermediary level in the epidermis), and 3 (large number of spirochetes present and reaching the deepest part of the epidermis or the superficial dermis). The improvement rate was 10/14 (71%) for salicylic acid, 11/15 (73%) for the inorganic acid solution, and 8/13 (62%) for the inorganic acid powder. The analysis showed no difference among treatments. The association between clinical score and histopathological score was determined by an odds ratio. The odds ratio of a healed lesion having spirochetes in the epidermis was 0.58 and that of an active DD lesion having spirochetes in the epidermis was 26.5.

Missing pieces of the puzzle to effectively control digital dermatitis

Since the first report of bovine digital dermatitis (DD) in 1974, there is a large body of the literature published; however, effective prevention and control of the disease remain elusive. Although many aspects of the pathogenesis of DD have been investigated, even some of the most basic questions such as the aetiology of this disease remain under debate. Treponema spp. have been strongly associated with DD lesions and occur in abundance in advanced lesions; however, efforts to induce disease with pure cultures of these organisms have been largely underwhelming and inconsistent. Furthermore, although the disease has been presented for several decades, there is limited scientific evidence regarding effective treatment of DD. Apparent discrepancies between effectiveness in vitro and in vivo have challenged the scientific community to identify new potential treatment options. With no treatment resulting in a 100% cure rate, the current expectation is manageable control, but prospects for the eradication of the disease are unlikely using current approaches. In order to develop more effective approaches to control DD on-farm, there is a critical need for a deeper understanding regarding the causation, ecology, transmission and treatment of this disease. In this article, we attempt to provide insights into specific research needs related to DD in order to assist the industry, researchers, pharmaceutical companies and research sponsors with decision-making and identified research gaps.

Prevalence of digital dermatitis in young stock in Alberta, Canada, using pen walks

Digital dermatitis (DD), an infectious bacterial foot lesion prevalent in dairy cattle worldwide, reduces both animal welfare and production. This disease was recently identified in replacement dairy heifers, with implications including increased risk of DD and decreased milk production in first lactation, poor reproductive performance, and altered hoof conformation. Therefore, a simple and effective method is needed to identify DD in young stock and to determine risk factors for DD in this group so that effective control strategies can be implemented. The objectives of this study were to (1) determine prevalence of DD in young stock (based on pen walks); and (2) identify potential risk factors for DD in young stock. A cross-sectional study was conducted on 28 dairy farms in Alberta, Canada; pen walks were used to identify DD (present/absent) on the hind feet of group-housed, young dairy stock. A subset of 583 young stock on 5 farms were selected for chute inspection of feet to determine the accuracy of pen walks for DD detection. Pen walks as a means of identifying DD lesions on the hind feet in young stock had sensitivity and specificity at the animal level of 65 and 98%, with positive and negative predictive values of 94 and 83%, respectively, at a prevalence of 37%. At the foot level, pen walks had sensitivity and specificity of 62 and 98%, respectively, with positive and negative predictive values of 92 and 88%, respectively, at a prevalence of 26%. Pen walks identified DD in 79 [2.9%; 95% confidence interval (95% CI): 2.3-3.6%] of 2,815 young stock on 11 (39%; 95% CI: 22-59%) of 28 farms, with all 79 DD-positive young stock ≥309 d of age. Apparent within-herd prevalence estimates ranged from 0 to 9.3%, with a mean of 1.4%. True within-herd prevalence of DD in young stock, calculated using the sensitivity and specificity of the pen walks, ranged from 0 to 12.6%, with a mean of 1.4%. On the 11 DD-positive farms, the proportion of young stock >12 mo of age with DD lesions was 9.9% (95% CI: 7.8-12.0%). Multilevel logistic regression was used to assess associations with potential risk factors for DD lesions, including age, leg cleanliness, and lactating herd DD prevalence. Presence of DD in young stock increased as their age increased and was associated with increased prevalence of DD in the lactating herd. Pen walks can be used to identify specific young stock with DD or groups where management practices can be implemented to prevent disease proliferation and transmission.

A Review of the Design and Management of Footbaths for Dairy Cattle

This article summarizes current footbath practices, questions the mechanism by which footbaths function, and reviews the available scientific literature testing footbaths in the field. Copper sulfate appears the most efficacious agent to include in a footbath program, but disposal concerns should limit the frequency of its use. Other agents such as formaldehyde have some merit when used with care. Use of water alone in a flush bath appears to have minimal impact. Footbaths should be used as infrequently as possible to achieve lameness prevention goals for the herd.

Effectiveness of a standardized footbath protocol for prevention of digital dermatitis

A footbath is the most common herd-level approach to control digital dermatitis (DD) in intensive dairy farming. However, wide variation in footbath design and protocols suggests a gap between evidence-based management practices and on-farm implementation. The objective was to evaluate effectiveness of a standardized footbath protocol in decreasing prevalence of active DD lesions in lactating dairy cattle. The protocol was based on current scientific literature, including footbath design and management. The M-stage classification system was used to score DD lesions. Scores were also combined into a simplified scoring system: no lesions (M0), active lesions (M1, M2, and M4.1), and chronic lesions (M3 and M4). A controlled intervention trial was conducted on 9 farms over 22 wk. Each farm served as its own control with data collected for 10 wk before and 12 wk after intervention. A total of 1,978 lactating cattle were assessed biweekly for DD lesions and leg cleanliness in the milking parlor. Lactating cattle were also inspected in the trimming chute at 3 time points: start, intervention, and end of trial. Intervention consisted of implementing an automated footbath that measured 3 m long, 0.50 m wide, held a fluid depth of 0.15 m, along with a weekly footbath protocol using 5% CuSO₄ for 4 consecutive milkings, with footbath content replaced at a maximum of 200 cow passes. Multilevel logistic regression models for repeated measures were used to evaluate effects of the standardized footbath protocol in preventing active DD lesions. For the purpose of analysis, farms' within-herd prevalence of active DD lesions (at baseline) was assessed and categorized as low (<15%) or high (≥15%). Farms with low or high within-herd prevalence of active DD lesions at trial outset had a mean cow-level prevalence of active DD lesions of 8% (range, 2 to 13) and 31% (range, 18 to 43), respectively. At milking parlor inspections, apparent prevalence of active DD lesions decreased from the time of footbath intervention, but this effect interacted with the farms' baseline prevalence of active DD lesions. In that regard, on farms with high prevalence of active DD at baseline, apparent prevalence of active DD lesions decreased after intervention, whereas on farms with low prevalence of active DD at baseline, apparent prevalence of active DD lesions did not change. At the cow level, poor leg cleanliness was associated with higher prevalence of active DD lesions. At trimming chute inspections, prevalence of active DD lesions decreased from start to the end of the trial (22 and 14%, respectively); concurrently, prevalence of feet with no DD lesions (M0) increased (39 and 48%). We concluded that on farms with high DD prevalence, implementation of proper footbath design and improvement of footbathing management will decrease prevalence of active DD lesions and increase prevalence of feet without DD lesions. In addition, improving cow cleanliness will further result in control of active DD lesions.

Association between digital dermatitis lesions and test-day milk yield of Holstein cows from 41 French dairy farms

The objective of this study was to estimate the association between digital dermatitis (DD) lesions and test-day milk yield (TDY) in dairy cows, taking into account the severity of the lesions. Data were collected for 6 mo on 47 French dairy farms endemically affected by DD and involved in a clinical trial aiming to assess the effectiveness of collective treatments against DD. The hind feet of all lactating cows were scored for DD by 14 trained investigators on a monthly basis using a 4-point M-stage scoring system (M0 to M4, M standing for Mortellaro). The DD status was defined in 3 categories at the animal level: no DD [scores of M0 and (or) M4 on both feet], moderate case (score of M1 on 1 or both feet and no M2 score), and severe case (score of M2 on 1 or both feet). All monthly TDY in the lactation were collected. The final complete data set included 7,599 TDY of 1,782 Holstein cows from 41 herds. The effect of DD lesions on the following TDY (i.e., within 30 d after detection of a DD lesion) was analyzed separately for primiparous and multiparous cows, using mixed-models ANOVA, with TDY as repeated measures. During the trial, 38% of the primiparous and 41% of the multiparous cows were observed at least once with a DD lesion (moderate or severe case), the cows being observed with a DD lesion, on average, for 2 consecutive visits. Milk yield decreased significantly for cows diagnosed with a DD lesion. Primiparous cows produced, on average, 0.63 kg/d less when DD was moderate and 0.50 kg/d less when the disease was severe, compared with unaffected cows. Multiparous cows produced, on average, 0.50 kg/d less when DD was moderate and 0.75 kg/d less when the disease was severe, compared with unaffected cows. These results confirm that DD lesions have a significant effect on the milk yield of dairy cows, including when animals are rigorously treated. Milk yield losses, thus, should be considered when evaluating the costs and benefits of DD control programs.

Estimation of the relative impact of treatment and herd management practices on prevention of digital dermatitis in French dairy herds

The purpose of this study was to concurrently estimate the effect of different digital dermatitis (DD) treatment regimens and herd management practices on the occurrence of a new DD lesion. A controlled clinical trial was conducted and involved 4678 dairy cows from 52 French dairy farms where DD was endemic. Farms were allocated by minimisation to one of 4 treatment regimens, varying through the mode (footbath or collective spraying) and the frequency of application (2 days every 4 weeks or fortnightly). They were visited 7 times every 4 weeks by 14 trained investigators. Frailty Cox proportional hazards models were used to estimate the relative effect of potential risk factors and treatment practices on the time until the first occurrence of a DD lesion. At herd level, high initial DD prevalence strongly increased the risk for DD occurrence (HR=1.93, CI 1.23-3.04), as well as absence of hoof-trimming (HR=1.75, CI 1.36-2.27) and poor leg cleanliness (HR=2.44, CI 1.80-3.31). At animal level, Holstein breed (HR=1.92, CI 1.35-3.57) and high-productive cows (HR=1.26, CI 1.01-1.56) were identified to be at higher risk for DD compared to Normande breed and low-productive cows, respectively. Compared to individual topical antibiotic treatments alone, collective treatments tended to decrease the risk of DD occurrence only when applied over 2 days at least every fortnight (HR range=0.64-0.73).