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Saturday 25 November 2017

Why one vet has changed the way he treats lameness in sheep

There are no magic bullets and it takes commitment from both the vet and the farmer to solve sheep lameness issues
There are no magic bullets and it takes commitment from both the vet and the farmer to solve sheep lameness issues
Tommy Heffernan

Tommy Heffernan

Over the last three years our practice has changed its approach to treating lameness.

Instead of treating individual lame sheep, we now look at the causes and hatch a plan. It has resulted in lameness falling from 15pc-20pc in flocks to below 5pc.

There are no magic bullets and it takes commitment from both the vet and the farmer to stick to the agreed plan

Most of what we do is based around the five-point lameness control plan. The plan is based around building resilience, reducing the amount of infection in the flock and establishing immunity.

This is a peak-risk period for lameness as we approach housing after grazing in wet conditions. Housing allows infectious agents build up in the straw and allows disease to spread even further.

The first step is to identify lame sheep and segregate them. Then we go through each one to classify the cause of the lameness. With these records, we can work out much better control plans.

The most common types of sheep lameness are:

1 Foot scald in between the hoof, causing reddening inflammation;

 

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2 Foot rot also affecting between the hoofs, causing more severe lameness and has a distinctive pungent odour;

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Foot rot

3 CODD (contagious ovine digital dermatitis) affecting above the coronary band, causing reddening and sometimes bleeding;

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Shelly hoof

4 Toe granuloma affecting the end of the toe, usually caused by overzealous paring;

5 Foot abscesses - these are small abscesses usually affecting the soft tissue inside the horn of the hoof;

6 Shelly hoof is exaggerated growth of the horn.

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CODD

The first four are by far the most common problems we diagnose. However, there are usually a number of these conditions contributing a flock lameness problem.

Having created a 'lame bunch', we set about treatment. Keeping these separate while treating usually reduces the spread of disease and allows more focused treatments.

Treatments for sheep lameness

1 Scald usually just requires footbathing. I use 1kg of zinc sulphate with 10 litres of water. I usually recommend three passes over three days, with once weekly footbathing thereafter. We also look at any conditions that might contribute to increased levels, such as winter bedding and stocking densities.

2 Foot rot usually requires injectable antibiotic treatments - you and your vet can decide the product and length of the course. It is really important to mark ewes that have been treated. Repeat offenders should be culled - three strikes and you're out should be standard. Footbathing here can also significantly reduce the risk of spread - in some severe cases, we use antibiotic footbaths for the first three days and then return to normal footbathing.

3 CODD will require antibiotic treatments and culling repeat offenders. Footbathing, in my experience, doesn't have a huge impact on CODD, meaning accurate diagnosis of this problem is very important.

4 Toe granuloma is where the horn of the claw is pared too much and the soft tissue underneath the hard horn protrudes out and becomes very sensitive and sometimes infected. We review paring techniques on the farm if we see a lot of this. Paring sheep should only be done where extremely necessary as it may significantly contribute to lameness and even spread infections in some cases.

5 We diagnose foot abscesses less commonly and they usually respond to antibiotic treatments if there isn't too much chronic tissue damage.

6 Shelly hoof is one condition where you can consider paring, but repeat offenders should be culled. This is true for any toe or horn deformities as they are difficult to get right long term.

Long-term strategy

Following a diagnosis and action plans being put in place, we review the flock lameness again one month after the first visit.

The second visit is about putting a long-term strategy in place, including:

1 Quarantine new arrivals on farm and assess for lameness over the first three weeks. Any infected sheep should be treated aggressively before entering the main flock. This is an essential plan, reducing lameness long term in your flock, as the main source of new infections can be bought-in stock.

2 Vaccination where foot rot is diagnosed has been very successful as a long-term control strategy. The use of footvax vaccine prior to risk periods and boosting annually can dramatically improve the sheep's ability to stop new infections of fusobacterium or foot rot.

3 We review treatments over time, carefully recording what treatments work and, more importantly. those that are not working. We also recommend the use of pain killers to fresh cases as, in my opinion, this helps with treatment outcomes.

4 We look at housing strategies long term to ensure ewe comfort and reduce the spread of infectious causes of lameness.

5 We have a distinct culling policy for repeat offenders to reduce the infection levels in the flock.

6 In many flocks, we establish routine footbathing to eliminate the spread of disease, particularly if we identify risk periods for certain flocks. Anyone dealing with lameness incidences of over 5pc should consider a flock lameness investigation and the role-out of the new Knowledge Transfer schemes creates a new opportunity to tackle flock lameness.

Tommy Heffernan is a Co Wicklow-based vet email: heffernantommy@yahoo.ie

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