20 Jun 2016
Sara Pedersen reviews a major conference, in Atlanta, Georgia, where the importance of what lies beneath the hoof was covered.
Sara Pedersen
Job Title
Figure 2. A “non-healing” wall ulcer pre-trimming, post-trimming and 17 days after therapeutic trimming.
A problem shared is a problem halved. When tackling hoof health issues on farm, it is undoubtedly easier to tackle through a team approach involving the farm’s staff, vet, nutritionist and hoof trimmer.
This was the focus of the Hoof Trimmers Association (HTA) Hoof Health Convention, held in Atlanta, US (Figure 1).
Formed in 1989 by US trimmer John Hooper, the HTA has grown to have nearly 600 members from across the globe. Conventions are held every 18 months, attracting members far and wide. This year was no exception, with more than 350 hoof trimmers attending from all over the world, including Japan, Chile, the UK and South Africa.
The convention kicked off with a pre-conference workshop led by Gerard Cramer of the University of Minnesota. He discussed the role of the trimmers as ambassadors for hoof care and the important role they play in disseminating key messages about lameness prevention and treatment.
The hoof trimmer is often the most knowledgeable person on the farm when it comes to the common causes of lameness; therefore, the ability to communicate concerns, advice and findings back to the farm manager and the wider farm team is critical for future improvement. However, hoof trimmers can often lack confidence in this area.
In small groups, delegates were asked to provide a short presentation about a specific subject area in hoof health and use different resources to present the information in an educational, interesting and motivating format for the farmer.
Following the workshop, delegates felt more confident about applying the communication skills in the field.
The full programme began the following day with Chuck Guard, of Cornell University, conducting an anatomy lab.
Open to anyone new to hoof trimming, or those wishing to have a refresher to keep up to date with knowledge, Dr Guard stressed the importance of knowing what lies beneath the hoof surface when trimming.
Since trimming is focused on lameness prevention, the importance of sticking to the guidelines set by the anatomy was clear, to stop the outcome being more detrimental than beneficial to the cow.
Milk residues following digital dermatitis treatment
Dr Cramer started the afternoon presentations with his “hoof research chips”, which gave an update on the latest research being conducted at the University of Minnesota, including some research funded by the HTA.
One particularly interesting study evaluated milk residues following topical tetracycline treatment of digital dermatitis (DD). Unlike the UK, no topical antibiotic aerosol is licensed for DD treatment in North America; therefore, tetracycline in powder form is often applied to lesions at varying doses.
Forty-five cows were included in the study, with the criteria both hindfeet had acute active ulcerative DD lesions – M2 on the Mortellaro scoring system. Cows were treated with various dosages of tetracycline (2,000mg, 5,000mg and 25,000mg), either in paste form or under a bandage. Milk samples, pre-udder and post-udder preparation, were taken to ascertain whether detectable tetracycline residues existed.
The results were quite alarming, with 5 of 45 cows having milk residues above 100 parts per billion (the Canadian maximum residue limit [MRL]; UK MRL is 100 parts per billion) eight hours post-treatment. Nearly 25% of all samples (taken from 8 hours to 168 hours post-treatment) had detectable levels of tetracycline, albeit below the MRL. The overall trend was for the application of higher levels of tetracycline to result in detectable milk residues for longer periods of time. Every cow tested had contaminated teats 24 hours after treatment, regardless of treatment dose.
The study highlighted the risk of milk residues not only in the individual cow, but also the potential for detectable levels in the bulk tank should significant numbers of cows in the herd be treated simultaneously with high doses of tetracycline.
Although Dr Cramer proved a hard act to follow, I was privileged to be next on the programme to talk about a case study I had conducted on “non-healing lesions”.
Chronically lame cows will inevitably have lower cure rates when treated, compared to cows that have been identified early in the course of disease; however, I firmly believe any “clinical improvement” is better than no improvement at all or, even worse, a deterioration.
A previous believer that “non-healing” meant exactly that, I have always approached these lesions with a scalpel blade and cheese wire rather than my hoof knives; however, with an ever-increasing hoard of pedal bones, I decided on a different approach.
Through thorough debridement of the lesion, thinning of the margins and an improved blocking technique, I have only reached for my cheese wire a handful of times in the past four years, predominantly due to the presence of joint sepsis.
Having recently completed a case series, including wall ulcers, toe necrosis and axial wall cracks, I was delighted to be able to share and discuss my results with an interested and interactive audience (Figure 2). In all cases, cows showed a clinical improvement in the degree of lameness over the follow-up period of two months and most cases showed increases in body condition scores and milk yield.
Continuing to follow these animals long-term will provide more information about the time taken for them to resolve their clinical signs of lameness and whether they have recurrent cases in the subsequent lactation.
Day two of the conference began with a presentation by Jan Shearer, of Iowa State University, discussing the dos and don’ts of treating lesions.
Starting with the basics of how lesions heal, Dr Shearer then pointed out the commonly used topical treatments are detrimental to this healing process. A US survey showed 59% of vets and 53% of hoof trimmers applied topical treatments, with tetracycline powder and copper sulphate used most frequently.
In his study, 18 cows with claw lesions were divided into three treatment groups – topical oxytetracycline powder and bandage, copper sulphate and bandage, and a control group with no treatment and a bandage. Lesions were scored 21 days after treatment for the visual presence of granulation tissue and evidence of re-epithelialisation.
Cows that received oxytetracycline or copper sulphate treatment were significantly more likely to have granulation tissue present and less likely to have evidence of re-epithelialisation.
Although the study was small, Dr Shearer suggested these topical treatments may delay wound healing and result in pain, since cows that received these treatments exhibited nearly three times as many pain-related behaviours following treatment compared to cows in the control group.
With the research presentations over, the focus shifted to the main theme of the conference – moving forward.
Presentations by Jennifer Walker, of Dean Foods, and Henry Holtmann highlighted the roles of the food processor and the farmer in the goal towards lameness reduction.
The common line was to achieve communication between all those involved in hoof health on the farm, and to ensure the whole farm team is motivated and aware of their role in achieving the farm’s goals (Figure 3). This theme was carried into a question panel with Dr Walker, Mr Holtmann and I, during which key points were raised by the audience and discussed.
Dealing with the neglected lame cows was a common concern for hoof trimmers around the world – who do they contact when they have a concern and at what point does the processor step in?
Before the conference ended, I was asked to talk about the UK dairy industry, its lameness prevalence, the National Association of Cattle Foot Trimmers – our trimmers association – and how the Agriculture and Horticulture Dairy Board dairy division’s healthy feet programme has helped bring trimmers and vets together.
While the programme is proven to be effective, the challenge remains as to how to engage farmers in discussions about lameness and prompt them to take action. It is clear the trimmer, vet and nutritionist all have a role to play in helping farmers make changes, and change is far more likely to occur when working together.
After an enjoyable, thought-provoking and motivating few days, it was time for delegates to let their hair down a little.
However, I must admit to being a little apprehensive about what exactly the evening entertainment would entail as “medieval nights” conjured up images of old medieval jousting competitions that couldn’t possibly take place in the centre of Atlanta… I was proven wrong.
An evening of medieval entertainment, with jousting on horseback, sword fighting and rose-throwing knights of the realm awaited (Figures 4 and 5).
There were a few bleary eyes on the buses the next morning as we travelled out of the city for the on-farm demonstration day. This was a great opportunity to see different crushes in action and continue discussions from the presentation days (Figure 6).
However, the real finale was the promise auction. Introduced to help finance the association, it now raises sufficient money every year to fund scholarship programmes and research grants so everyone in the association can contribute to “moving forwards” in whichever way they can.
The author thanks hoof trimmers Alun Howells (Carmarthenshire) and Joe Kirby (Cheshire) for their help and patience during her non-healing lesion case series.
