Efficacy of salicylic acid in the treatment of digital dermatitis in dairy cattle

Comprehensive toxicological screening of common drugs of abuse, new psychoactive substances and cannabinoids in blood using supported liquid extraction and liquid chromatography-quadrupole time-of-flight mass spectrometry

Immunoassay (IA) is currently the most widely used technique for toxicological screening in drug-impaired driving investigations. However, practical limitations in the scope of testing, and the emergence of new psychoactive substances (NPSs), have highlighted the need for alternative approaches, particularly mass spectrometry-based screening. High-resolution mass spectrometry broadens the scope of testing to include NPSs and increases analyte specificity compared to IA. In addition, it provides a platform with increased flexibility and adaptability to incorporate emerging drugs of interest due to the transient drug market. In this study, a comprehensive screening procedure was developed to identify >200 drugs of interest, including cannabinoids and NPSs in whole blood. Supported liquid extraction and liquid chromatography-quadrupole time-of-flight mass spectrometry using All Ions data acquisition were used. The method was validated in accordance with published recommendations, and all compounds of interest were identified at recommended cutoffs for driving under the influence of drug investigations. Cannabinoids, including 11-nor-9-carboxy-∆9-tetrahydrocannabinol, fentanyl analogs, buprenorphine, novel synthetic opioids and synthetic cannabinoids, were identified at low- to sub-nanogram/milliliter concentrations in whole blood using both positive and negative electrospray ionization acquisition methods.

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.

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.

Methylene blue-mediated antimicrobial photodynamic therapy can be a novel non-antibiotic platform for bovine digital dermatitis

BACKGROUND

Bovine digital dermatitis (BDD) is one of the most important diseases that effect dairy cows. Methylene blue-mediated antimicrobial photodynamic therapy (MB-APDT) emerges as a promising technique to treat superficial infections in bovines.

METHODS

Twenty BDD lesions located at the skin horn transition of the claw of pelvic limbs of 16 cows were treated by MB-APDT, using a red LED cluster (λ = 660 nm, irradiance =60 mW/cm², exposure time = 40 s) combined with topical application of MB at 0.01 %; or by topical application of OXY (500 mg in 20 % solution). Each lesion was treated twice with an interval of 14 days. Lesions were weekly evaluated until day 28 by clinical analysis and by histological examination on days 0 and 28.

RESULTS

Both treatments led to a similar reduction of lesions area. At day 28, three lesions treated by OXY did not present completely recovery, whereas no lesions were observed in MB-APDT group. OXY resulted in a slight increase in type I and III collagen levels, while MB-APDT led to a significant increase in the total area of both collagen types. An abundant number of spirochetes were histologically observed in all lesions before treatments. On the 28th day, five lesions treated by OXY still presented a slight number of spirochetes, whereas in MB-APDT group no spirochetes were evidenced.

CONCLUSION

Our findings suggest that MB-APDT is more effective than OXY and could be used in Veterinary practice to fight BDD.

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).

Comparison of the therapeutic efficacy of salicylic acid paste with a polyurethane wound dressing for the treatment of digital dermatitis lesions in dairy cows

There is little evidence of the efficacy of artificial polymers for controlling bovine digital dermatitis (BDD) as a major problem of intensive dairy productions worldwide. We therefore aimed to compare salicylic acid (SA)-based paste with a polyurethane (PU) wound dressing on a German Holstein dairy farm over a maximum 56-d period. On d 0, 109 ft with active BDD lesions from 109 cows were randomly assigned to two treatment groups: (1) SA group received a topical SA-containing paste and (2) PU group was treated with a PU wound dressing. Dressing changes were performed according to manufacturer's instructions until clinical cure (transition from active M1 or M2 to non-active M4 or healed M0 stages), whereby a clinical scoring of lesions was additionally conducted. Data from 100 ft could be analyzed (n_SA = 54; n_PU = 46). There was a significant reduction of the lesion score over time within each group (SA: d 0-d 14; PU: d 0-d 28, p < .05). Score differences between first (d 0) and second (SA: d 7; PU: d 14) as well as between first and third (SA: d 14; PU: d 28) evaluation did not differ significantly (p > .05). The proportion of clinically cured cows was higher in SA than in PU on d 14 (96.3 vs. 32.6%) as well as on d 28 (100 vs. 54.3%) after initial treatment (p < .05). Analysis of survival to cure in a Cox regression model showed that hazard ratio (HR) was higher for SA with PU as baseline (HR: 6.324, 95% CI: 3.625-11.033, p < .05). However, while BDD scores at enrollment did not differ between treatments (p > .05), PU had a significantly lower final BDD score (p < .05). In conclusion, evidence on the efficacy of PU bandages to treat BDD lesions is provided and further studies on bacteriological cure as well as recurrence rates are needed.

Interobserver agreement of digital dermatitis M-scores for photographs of the hind feet of standing dairy cattle

Digital dermatitis (DD) is the leading infectious cause of lameness in dairy cattle, and it affects their welfare and productivity worldwide. At the herd level, DD is often assessed while cows are standing in a milking parlor, and lesions are most commonly evaluated using the M-score. The objective of this study was to examine the interobserver agreement for M-scores of the feet of standing cattle, based on digital color photographs of dairy cattle hind feet. A total of 88 photographs and written descriptors of the M-score were sent to 11 scorers working at 10 different institutions in 5 countries. The scorers received no formal training immediately before scoring the photographs; however, all regularly used the M-score to score DD. The answers for 36 photographs were excluded from the analysis because the photograph either had more than 1 M-stage as mode or not all scorers assigned an M-score to it. The M-scores of the 11 scorers from 52 photographs were available for analysis. Interobserver agreement was tested using Gwet's agreement coefficient (AC1) and the mode was assumed correct. Overall, moderate agreement emerged for the M-score (AC1 = 0.48). For the individual M-stages, almost perfect agreement existed for M0 (AC1 = 0.99), M1 (AC1 = 0.92), and M3 (AC1 = 0.82), and substantial agreement for M2 (AC1 = 0.61), M4 (AC1 = 0.65), and M4.1 (AC1 = 0.71). This outcome indicates the degree of individual variation in M-scoring in this context by unstandardized, experienced European observers, particularly for the M2, M4, and M4.1 stages. Standardized training is likely to improve the consistency of M-scoring and thus the generalizability of future DD research results on this important endemic disease.

A Case-Series Report on The Use of a Salicylic Acid Bandage as a Non-Antibiotic Treatment for Early Detected, Non-Complicated Interdigital Phlegmon in Dairy Cows

Simple Summary

Interdigital phlegmon (IP) is a common and economically important cause of acute lameness in cattle. It is most often treated with antibiotics. To reduce the use of antibiotics, we wanted to evaluate the effect of treatment with a salicylic acid bandage of the hoof of early-detected IP in dairy cows. We found that treatment by farmers of mild IP with salicylic acid was generally satisfactory. Within three to five days, treated cows responded with reduced lameness, lower body temperature, decreased swelling, and an improved general condition compared with the day when the treatment started. The salicylic acid bandage therefore showed the potential to be an attractive alternative in the treatment of early detected, non-complicated IP. The benefits of using salicylic acid instead of antibiotics include reduced risk of antimicrobial resistance, no painful injections of antibiotics, cheaper treatment costs, and no withdrawal of milk. However, it is important that the diagnosis is correct and that other claw disorders and complications are identified and treated promptly.

Abstract

Interdigital phlegmon (IP) is an important cause of lameness in cattle. The aim of this study was to evaluate the treatment effect of a salicylic acid bandage in the interdigital space in dairy cows with early detected IP. Dairy cows (n = 109) with IP diagnosed and treated by the farmer were included in the study. On day 0, the rectal temperature, general condition, coronary circumference, and lameness score were recorded. The cow was immobilized in a trimming chute and the interdigital space was cleaned and inspected. For treatment, 1–2 tablespoons of 100% salicylic acid powder were applied into the interdigital space followed by bandaging of the hoof. On days 1–2 and days 3–5, the rectal temperature, the general condition, and the lameness score were recorded. On days 3–5, the cow was restrained, the bandage was taken off, and the coronary circumference was recorded again. Treatment of IP with salicylic acid gave a satisfactory treatment result. Within three–five days, treated cows responded with reduced lameness, lower body temperature, decreased coronary swelling, and an improved general condition compared to the day when the treatment started. Salicylic acid therefore proved to be an alternative in the treatment of early-detected non-complicated IP.

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.

The therapeutic efficacy of allyl isothiocyanate in cows with bovine digital dermatitis

Bovine digital dermatitis (BDD) is the most prevalent infectious cause of lameness in cattle. Because Treponema infection is a major etiology of BDD, the most common treatment of BDD is an antibiotic. Nonetheless, dairy cows require a withdrawal period after antibiotic treatment before their milk can be marketed. To address the problem, in this study, we tested whether 3 nonantibiotic agents (used separately)—allyl isothiocyanate (AITC), sodium alginate, and calcium hydroxide—alleviate BDD lesions in dairy cows. The AITC treatment improved the BDD lesions, whereas the sodium alginate and calcium hydroxide treatments did not. Therapeutic efficacy of AITC was similar to that of lincomycin, a topical antibiotic prescribed for BDD. These results suggest that AITC is a promising nonantibiotic agent for BDD treatment in dairy cows.

Polyurethane dressing, tetracycline and salicylic acid use for treatment of digital dermatitis in cattle. A comparative study

OBJECTIVE

The use of antibiotics is a proven approach for local and systemic treatment of digital dermatitis (DD). Even if they are administered only locally and at low dosage, their use should be restricted to an absolute minimum. The efficacy of a commercial polyurethane wound dressing in treating acute digital dermatitis was compared with topical treatment using a commercially available tetracycline spray and a salicylic acid paste.

MATERIALS AND METHODS

A total of 105 cows in a dairy farm (with about 160 dairy cows) were included in the study, with 101 cows needing topical treatment for digital dermatitis on one or both hind feet. All animals underwent hoof trimming prior to the treatment. Affected feet (n = 152) were randomly assigned to one of three comparable treatment groups. Topical treatment was administered to all visible digital dermatitis lesions. Animals in the positive control groups were given a topical treatment of tetracycline (53 DD lesions in 49 cows) or salicylic acid (53 DD lesions in 50 cows) formulations, whose therapeutic effects were scientifically verified. Spray was applied once, at a usual dosage and without any bandage. Salicylic acid paste was fixed in place with a bandage for 5 days. In the test group (46 DD lesions in 45 cows), a polyurethane bandage was left in place for 10 days. Whereas, 47 feet (from 38 cows) without lesions or with lesions showing no pain were designated as group 0. Each lesion was evaluated at day 0 during trimming, and on day 10 and 36. The lesions were scored based on severity and size.

RESULTS

All groups showed a statistically significant improvement in the clinical appearance of the lesions at day 10. There were no significant differences in the findings between the second and the third evaluation (day 10 and day 36) either within a group or between the groups.

CONCLUSION

The use of an alternative treatment regimen like a polyurethane wound dressing shows good clinical healing, it is as effective as the conventional methods, and unlike the conventional methods, does not require a latency period.

Bovine digital dermatitis: Current concepts from laboratory to farm

Bovine digital dermatitis (DD) is a severe infectious disease causing lameness in dairy cattle worldwide and is an important ruminant welfare problem that has considerable economic issues. Bovine DD is endemic in many regions worldwide and it is important to understand this major disease so that effective control strategies can be identified. There is substantial evidence that specific treponeme phylotypes play an important causative role in bovine DD. This review considers current research, including DD Treponema spp. investigations, associated DD pathobiology, and current and potential treatment and control options. Epidemiological data, alongside new microbiological data, help delineate important transmission routes and reservoirs of infection that allow effective interventions to be identified. Better on-farm housing hygiene, pasture access, routine footbathing and claw trimming with disinfected equipment need to be implemented to significantly reduce the incidence of DD. There is a paucity of peer reviewed research into both commonly used and novel treatments. In vitro antimicrobial susceptibility studies of DD treponemes and effective treatment of human treponematoses clearly indicate that antibiotics frequently selected for DD treatments are not the most efficacious. Whilst there are understandable concerns over milk withdrawal times in dairy cattle, more needs to be done to identify, license and implement more appropriate antibiotic treatments, since continued overuse of less efficacious antibiotics, applied incorrectly, will lead to increased disease recurrence and transmission. More research is needed into methods of preventing DD that circumvent the use of antibiotics, including vaccination and transmission blocking studies, to reduce or hopefully eradicate DD in the future.