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.

Associations between hair trace mineral concentrations and the occurrence of treponeme-associated hoof disease in elk (Cervus canadensis)

BACKGROUND

Trace minerals are important for animal health. Mineral deficiency or excess can negatively affect immune function, wound healing, and hoof health in domestic livestock, but normal concentrations and health impairment associated with mineral imbalances in wild animals are poorly understood. Treponeme-associated hoof disease (TAHD) is an emerging disease of free-ranging elk (Cervus canadensis) in the U.S. Pacific Northwest. Selenium and copper levels identified in a small number of elk from areas where TAHD is established (i.e., southwestern Washington) suggested a mineral deficiency may have increased susceptibility to TAHD. Our objectives were to determine trace mineral concentrations using hair from elk originating in TAHD affected areas of Washington, California, Idaho, and Oregon and assess their associations with the occurrence of the disease.

RESULTS

We identified limited associations between TAHD occurrence and severity with hair mineral concentrations in 72 free-ranging elk, using Firth's logistic regression and multinomial regression models. We found consistent support for a priori hypotheses that selenium concentration, an important mineral for hoof health, is inversely associated with the occurrence of TAHD. Less consistent support was observed for effects of other minerals previously associated with hoof health (e.g., copper or zinc) or increased disease risk from potential toxicants.

CONCLUSION

Trace mineral analysis of hair is a non-invasive sampling technique that offers feasibility in storage and collection from live animals and carcasses. For some minerals, levels in hair correlate with visceral organs that are challenging to obtain. Our study using hair collected opportunistically from elk feet submitted for diagnostic investigations provides a modest reference of hair mineral levels in elk from the U.S. Pacific Northwest that may be useful in future determination of reference ranges. Although our results revealed high variability in mineral concentrations between elk, consistent relationship of possibly low selenium levels and TAHD suggest that further investigations are warranted.

Impact of Nutrients on the Hoof Health in Cattle

Lameness is currently one of the most important and economically demanding diseases in cattle. It is manifested in a change in locomotion that is associated with lesions, especially the pelvic limbs. The disease of the hoof is painful, affecting the welfare of dairy cows. Important factors that influence the health of the limbs include nutrition, animal hygiene, stable technology, and genetic and breeding predispositions. Nutrition is one of the basic preventive factors affecting the quality and growth of the hoof horn, and the associated prevalence of hoof disease. The strength and structure of the hoof horn are affected by the composition of the feed ration (amino acids, minerals, vitamins, and toxic substances contaminating the feed ration, or arising in the feed ration as metabolites of fungi).

Treponeme-Associated Hoof Disease of Free-Ranging Elk ( Cervus elaphus) in Southwestern Washington State, USA

A novel foot disease in free-ranging elk ( Cervus elaphus) in southwestern Washington State emerged in 2008 and spread throughout the region. Initial studies showed adult elk had chronic hoof overgrowth, sole ulcers, and sloughed hoof capsules, but no cause was determined. To identify possible causes and characterize the earliest lesions, 9-, 7-, and 3-month-old elk were collected. Nine-month-old elk had sole ulcers (3/9 elk) and sloughed/overgrown hoof capsules (4/9 elk) similar to adults. Histologically, lesions consisted of coronary, heel bulb, and interdigital ulcers with suppurative inflammation, epithelial hyperplasia, deeply invasive spirochetes, and underrunning of the hoof capsule and heel-sole junction. Spirochetes were identified as Treponema via immunohistochemistry and polymerase chain reaction (PCR). Seven-month-old elk had similar underrunning foot ulcers (6/8 elk) with Treponema identified in all lesions but no chronic overgrowth or sloughed hoof capsules. Three-month-old calves had superficial coronary erosions with no inflammation or identifiable spirochetes (3/5 elk) but were culture/PCR positive for Treponema, suggesting possible early lesions. Lesions from 9- and 7-month-old elk included aerobic and anaerobic bacteria, many of which are associated with infectious foot disease in livestock. Antibody enzyme-linked immunosorbent assay of 7- and 3-month-old elk from the enzootic region showed a trend toward increased Treponema antibody titers compared to normal control elk from outside the region, further supporting the significance of Treponema in the pathogenesis of foot disease. Treponeme-associated hoof disease (TAHD) in elk, a debilitating and progressive condition, shares similarities to bovine digital dermatitis and contagious ovine digital dermatitis.

Combination effect of allyl isothiocyanate and hoof trimming on bovine digital dermatitis

Digital Dermatitis is a localized infectious dermatitis caused by Treponema-like spirochetes. Antibiotics, such as lincomycin, are currently used for treatment, but their use imposes a withdrawal period. This study investigated the therapeutic effect of topical application of the natural component allyl isothiocyanate, in combination with maintenance hoof trimming, on bovine Digital Dermatitis. Study cows were divided into two groups, the Trimming Group and Non-Trimming Group. The day when allyl isothiocyanate was applied, along with hoof trimming, was set as Day 0. Lesion scores, pain, and the presence of Treponema-like spirochetes on the surface of hooves and in biopsy samples of the tissues were evaluated until Day 6. Both groups showed improvement of lesion scores and improved elimination of Treponema-like spirochetes from within the tissues. The presence of Treponema-like spirochetes on the surface of lesions was significantly higher in the Non-Trimming Group by Day 6. These results suggest that allyl isothiocyanate has therapeutic effects on Digital Dermatitis, when combined with hoof trimming, and may prevent a relapse of dermatitis and a re-infection of Treponema-like spirochetes.

Farm level risk factors for bovine digital dermatitis in Taranaki, New Zealand: An analysis using a Bayesian hurdle model

As part of a cross-sectional study of bovine digital dermatitis (BDD) in 60,455 cows across 224 herds, in Taranaki, a region of the North Island of New Zealand, from September 2014 to February 2015, questionnaires from 114 farms were analysed to identify the key management practices which affect the probability of a farm being affected by BDD and the prevalence of an individual cow being affected on affected farms. The data from the questionnaires were analysed using a Bayesian hurdle model. Two factors were identified as being associated with farm level infection status: (1) milking parlour type; farms which had rotary platforms were more likely to be recorded as having BDD than those which had herringbone parlours (odds ratio, OR, 3.19; 95% probability interval, PI, 1.31-8.51); and (2) young stock movement; farms whose young stock were reared on farms alongside heifers from other farms had a higher odds of being BDD positive than farms where heifers were kept separate (OR 4.15; 95% PI 1.39-15.27). Two factors were associated with an increase in the prevalence of BDD within affected farms: (1) farms which used outside staff to trim feet had a higher prevalence of BDD (prevalence ratio, PR, 3.13; 95% PI 1.25-7.29) than farms which did not use outside staff; and (2) farms examined in spring (September to November) had a higher prevalence of BDD (PR 2.16; 95% PI 1.05-4.43) than farms examined in summer (December to February).

Evaluation of the prevalence of digital dermatitis and the effects on performance in beef feedlot cattle under organic trace mineral supplementation

Bovine digital dermatitis (DD) is a contagious and multifactorial disease that leads to painful, ulcerative lesions of the skin near the heel-horn border of the foot, most commonly in dairy cattle. With regard to beef cattle, the pathogenesis and etiology of DD has not been widely reported or studied over the past several decades. A longitudinal field trial in a commercial feedlot was conducted to compare prevalence and effects of DD in beef steers provided a diet supplemented with a novel formulation of inorganic and organic trace mineral sources (OTM diet) compared to a diet provided with similar levels of trace minerals solely from inorganic sources (CON diet). A secondary objective was to evaluate the prevalence of DD and the potential effects on growth performance and carcass yield and quality. One thousand seventy-seven steers were assigned to 1 of the 2 treatment groups (CON diet or OTM diet) based on location of their home pens which were situated in 1 of 2 barns. All pens in the B barn (group B) were assigned to the OTM diet, and all pens in the A barn (group A) were assigned to the CON diet. The study was conducted in 2 phases: adaptation phase (AP) comprising the initial 60 d of feeding CON and OTM diets and postadaptation phase (PAP) which lasted until cattle were sent to harvest. In the AP, pens in group B had a greater proportion of steers (54.03%) with DD lesions compared to pens in group A (26.72%). During the PAP, the relative risk of observing an increased DD prevalence was significantly ( < 0.05) higher in CON group compared to OTM group. Growth performance, final live weight, and hot carcass weight were negatively impacted when steers were observed to have active DD lesions (M2 lesions) compared to steers with no M2 lesions over the study period. For ADG, a calculated loss per steer of 0.08 kg/d from type I (no M2 lesions) to type II (one M2 lesion; SE = 0.028; = 0.003) and loss of 0.14 kg/d from type I to type III (multiple M2 lesions; SE = 0.038; = 0.0003) were observed. A significant BW loss of approximately 10.06 kg (SE = 4.18; = 0.022) and a mean reduction of 5.5 kg per steer in HCW (SE = 2.74; = 0.043) were also found between type I and type II steers.

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.

Pathogenesis and Treatment of Toe Lesions in Cattle Including "Nonhealing" Toe Lesions

Toe lesions in cattle include apical white line disease, thin soles, toe ulcers, toe necrosis, digital dermatitis-associated toe ulcers/toe necrosis, and fracture of the claw capsule and the apex of the distal phalanx. For anatomic reasons, the early stages of toe abnormalities (thin sole, apical white line disease, toe ulcer) are at risk of developing into a bone infection. The prevalence of toe lesions differs in dairy herds and feedlots: it is low at the animal level in feedlots and dairies; however, the herd prevalence of toe lesions can reach 50% in dairy herds with endemic digital dermatitis infection.

Clinical Perspectives of Digital Dermatitis in Dairy and Beef Cattle

Digital dermatitis is a polybacterial disease process of dairy and beef cattle. Lesions are most commonly identified on the plantar aspect of the interdigital cleft of the hind limbs. Treponema spp are routinely present in large numbers of active lesions. Lesions are painful to the touch and can result in clinical lameness. The infectious nature generally results in endemic infection of cattle herds and management requires a comprehensive and integrated multipronged approach. This article provides current perspectives regarding management and treatment of digital dermatitis on dairy and beef cattle operations and provides a review for clinicians dealing with a clinical outbreak.

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.

Digital Dermatitis in Dairy Cows: A Review of Risk Factors and Potential Sources of Between-Animal Variation in Susceptibility

Simple Summary

Dairy cow lameness is a major problem for the industry, causing reduced animal welfare and economic loss. Digital dermatitis (DD) is a bacterial disease causing painful lesions, generally on the heels of the rear feet, and is an important cause of lameness. There appears to be individual variation between animals in susceptibility to this disease. Particular physical, physiological and behavioural factors might influence individual susceptibility, but further work is required to clarify the influence of these factors and to determine how this information could be used to develop breeding and management strategies to reduce DD prevalence.

Abstract

Digital dermatitis (DD) is a bacterial disease that primarily affects the skin on the heels of cattle. It is a major cause of lameness in dairy cows and a significant problem for the dairy industry in many countries, causing reduced animal welfare and economic loss. A wide range of infection levels has been found on infected farms, prompting investigations into both farm level and animal level risk factors for DD occurrence. There also appears to be individual variation between animals in susceptibility to the disease. The identification of factors affecting individual variation in susceptibility to DD might allow changes in breeding policies or herd management which could be used to reduce DD prevalence. Factors mentioned in the literature as possibly influencing individual variation in susceptibility to DD include physical factors such as hoof conformation and properties of the skin, physiological factors such as the efficacy of the immune response, and behavioural factors such as standing half in cubicles. Further work is required to determine the influence of these factors, identify the genetic basis of variation, clarify the level of heritability of DD susceptibility and to determine how this is correlated with production and health traits currently used in breeding programmes.

Effect of including canola meal and supplemental iodine in diets of dairy cows on short-term changes in iodine concentrations in milk

The dietary requirement for iodine is based on thyroxine production, but data are becoming available showing potential improvements in hoof health when substantially greater amounts of I are fed. Feeding high amounts of I, however, can result in the milk having excessive concentrations of I. Canola meal contains goitrogenic compounds that reduce the transfer of I into milk. We hypothesized that including canola meal in diets would allow high supplementation rates of I without producing milk with unacceptable concentrations of I. Thirty midlactation Holstein cows were fed a diet with all supplemental protein from soybean meal (0% of diet dry matter as canola meal) or with all supplemental protein from canola meal (13.9% canola meal). A third treatment has a mix of soybean meal and canola meal (3.9% canola meal). Within canola-meal treatment, cows were fed 0.5 or 2.0mg of supplemental I per kilogram of diet dry matter from ethylenediamine dihydroiodide. Cows were maintained on the canola treatment for the duration of the experiment but were changed from one I treatment to the other after 13d of receiving the treatment. Milk I concentration before the treatments started (cows fed 0.5mg/kg of I) averaged 272μg/L and increased within 22h after cows were first fed diets with 2mg/kg of I. As inclusion rate of canola meal increased, the concentration of I in milk decreased linearly. After 12d of supplementation, milk from cows fed 0.5mg/kg of I had 358, 289, and 169μg of I/L for the 0, 3.9%, and 13.9% canola-meal treatments. For cows fed 2.0mg/kg of I, milk I concentrations were 733, 524, and 408μg/L, respectively. Concentrations of I in serum increased with increased I supplementation, but the effect of canola meal was opposite of what was observed for milk I. Cows fed the highest canola-meal diets had the highest serum I whether cows were fed 0.5 or 2.0mg/kg of I. Feeding dairy cows diets with 13.9% canola meal maintained milk I concentrations below 500μg/L when diets were supplemented with 2mg/kg of I.