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Seven possible causes of toe lesion discussed at meeting

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01 July 2011, at 1:00am

JON READER presents the second of three reports from the international conference on lameness in ruminants held earlier this year in New Zealand

DURING the Lameness in ruminants conference and symposium held earlier this year in Rotorua, New Zealand, Nigel Cook presented some of his observations on footbath design. 

He believed that to achieve “two dunks” on each foot per cow, a footbath needed to be at least three metres in length. He advocated removing the pre-wash bath as in his view this actually led to more contamination in the treatment bath. 

Numerous studies were described looking at the efficacy of different foot-bathing regimes and the author recommended that these be accessed via the web on IVIS. 

One particular product that seems to have caught the attention of some researchers is an acid that can be added to copper sulphate to increase the availability of the copper. This reduces the quantity of copper sulphate required but more importantly reduces the waste products and minimises pasture contamination with copper. 

Treponemes have been long associated with digital dermatitis. However, the routine use of PCR has allowed researchers to look at other diseases and to see if treponemes are present. 

Non-healing lesions 

Roger Blowey presented some work to demonstrate that treponemes are being increasingly identified in nonhealing lesions of the foot including white line disease, sole ulcers and toe necrosis. 

He described how he is increasingly advising the use of a long-acting antibiotic in such cases. 

Van Amstel et al described a similar condition in Tennessee involving atypical dermatitis lesions and suggested the topical application of dexamethasone as a treatment option. Hozhauer was one of the first people to report these non-healing lesions and his recommendation was to consider the use of acetyl-salicyl acid. 

In a different talk, Van Amstel also looked at the pathophysiology and differentiation of toe lesions. He listed seven possible causes of toe lesion which included toe ulcers. It was his opinion that this should be differentiated from white line disease occurring in zone 1 and 2 on the foot. 

Clearly, more work needs to be done to elucidate what is causing these lesions in the UK as my personal opinion is that this is an ever increasing problem. 

Treponemes have also been identified in lesions associated with ulcerative mammary dermatitis (Read et al). PCR has demonstrated the presence of the important treponemes deep in the dermis and it is suggested that these are associated with the disease process. 

It is important, however, to acknowledge that their presence does lead to a causal link and thus far these treponemes have not been cultured from these sites. 

Nigel Cook summarised some of his findings of lameness over the transition period. Lying times reduced in the hours leading up to calving and this was accompanied by an increase in number of lying bouts but of decreased duration.

Dramatic increase 

Lame cows, however, showed a dramatic increase in lying bouts and he hypothesised that this alteration was associated with hypersensitivity to pain due to lameness. Also, lame cows during the dry period had higher levels of ketones than non-lame cows, increasing the risk of ketosis. 

Traditionally, only milking cows have been mobility scored but this might suggest that a mobility score of the prefresh group may be valuable and then lame cows managed differently. 

Another member of Nigel’s research group demonstrated that the three variables that affected time budgets in milking cows the most were time out of the pen for milking, stall base type and lameness.

Hypersensitivity 

On the subject of hypersensitivity, Richard Laven looked at the effect of NSAIDs on hyperalgesia caused by lameness. 

He summarised that analgesia as provided by NSAIDs may not work very long but that they do reduce hyperalgesia in the short term. It was well recognised by all the delegates that the application of a hoof block was probably the most important aspect of pain relief. 

Richard explored the problems with farmer recognition of lameness. He used survival curve analysis, highlighting that 25% of cows with a score 3 (Sprecher scale) waited a month to have their feet picked up while 40% of cows with a score 3 were never presented for lameness treatment. 

Groenevelt et al quantified the benefits of early treatment and demonstrated that a delay of two weeks before treatment reduced apparent cure rates by 15%.

Rubber matting 

Christer Bergstein presented several posters on his continued work on rubber matting. He demonstrated that a slightly roughened rubber mat may provide a more natural wear for dairy cows than smooth matting. 

On the same subject, Eicher evaluated the presence of inflammatory mediators on cows on concrete compared to rubber. These were greater in the concrete-housed cows and may be useful in the future as early indicators of lameness. 

In relation to cow comfort in a cubicle setting, Roger Blowey presented his findings on rib swellings and said there was a high probability of a cow having a palpable rib swelling with increased lameness score. 

John Huxley reported on Potterton’s preliminary findings in relation to hock scores. Hock lesions were prevalent in their large sample and were significantly associated with elevated locomotion score. 

He questioned the cause and effect relationship of hock lesions and lameness and suggested that hock lesions may be a cause of lameness in their own right.