Happy Feet! - How to Combat Occasional and Persistent Lameness in Your Flock

lameness-sheep-kneeling

As a prey species, sheep are generally rather stoical creatures – it’s not in their best interest to show any sign of weakness that would make a predator think it might be an easy meal! So, if you spot a sheep limping, or grazing on its knees, you know that its feet are really hurting. Left untreated, they will, without doubt, deteriorate further, as well as spread disease to the rest of the flock. They certainly will not get better by themselves.

Farmers have cited lameness as the number one production-limiting factor in sheep farming, and recent industry studies suggest a figure of around 10% (roughly 3 million) of the national flock is lame at any one time.

Why lameness is an important issue for all sheep keepers:

  • Welfare – if a sheep is limping, or on her knees, or sitting for excessive amounts of time, it means the animal is in pain: left untreated the condition will only worsen.
  • Productivity – lame sheep will spend less time grazing, and ewes may be unwilling to stand and let their lambs suckle: the ewe’s condition will deteriorate, she may develop mastitis and her lambs’ growth will inevitably be retarded.
  • Workload – for the shepherd, gathering the flock, footbathing and treating individual sheep is time-consuming, backbreaking work – and unless it’s done properly, can be a total waste of time.
  • Cost – of footbath solutions, sprays, veterinary attention and antibiotics.
  • Ethical – increasing antibiotic resistance is a real concern, as is their overuse in animals destined for the human food chain.
  • Loss of stock­ – a sheep that is chronically lame is likely to be prematurely culled from the flock for the reasons above.
  • Management – it’s illegal to transport sheep with obviously painful feet, so they cannot be taken to market, or to the abattoir.
  • Public Perception – visitors to the countryside seeing limping sheep may think that the farmer is neglecting his sheep, resulting in a negative perception of the industry.

In the past few years there have been a number of initiatives aimed at stamping out lameness in sheep once and for all, and yet we still see painfully limping sheep in fields. Does this mean that sheep are physiologically prone to having bad feet and we, and they, just have to put up with it? Or is there another reason – perhaps the mass of information is simply too complicated to put into practice? The truth is that neither of these statements is correct; with a planned and determined approach farmers and smallholders can all but eliminate lameness from their flocks.

The universal recommendation is to CATCH + TREAT an affected sheep as a matter of urgency; don’t leave it until you want to bring the whole flock in, as a single lame sheep left untreated will only get worse and will spread disease amongst the flock.

Treatment Protocols

1 – LOCOMOTION SCORE on a scale of 1(sound) to 5 (very lame)

2 – CATCH any sheep with a score of 2+ as soon as possible (ideally within 24hours)

3 – TIP & EXAMINE: clean the affected foot so you can clearly see the affected area

4 – IDENTIFY each condition requires specific treatment, so identification is vital

5 – TREAT immediately and appropriately for the specific condition

6 – MARK treated sheep so you can monitor their progress following treatment

7 – RECORD all incidences of lameness, scores, dates, treatment and outcome

You’ll need to ‘tip’ the sheep in order to inspect its feet, if you can justify the cost, incorporating a ‘turnover crate’ in your handling system will ease the back-breaking job of manually tipping each sheep.

Not all lameness is caused by the dreaded footrot, but even an apparently simple case of scald can progress to something much more serious if not nipped in the bud.  

Foot Problems & Causes of Lameness In Sheep

lameness-inspecting-footWhen inspecting the foot, feel for heat as this can indicate infection deep in the structure of the foot. Many diseases of the feet have similar appearance, so if you are unsure contact your vet for an accurate diagnosis – a callout will ultimately save money, as the wrong treatment can enable disease to spread amongst the flock.

  • Scald – (also called Interdigital Dermatitis) is the most common cause of lameness, especially in young lambs. The causative organism (Fusobacterium Necrophorum) thrives in warm wet weather, especially when the sheep are on long grass which can rub the skin between the two claws of the foot, making them sore and allowing bacteria to infect the skin. Scald is often the precursor to more serious conditions.
  • Footrot – the bacteria (F. Necrophorum + Dichelobacter nodosus)are naturally present in the soil; mild, wet weather and muddy fields tend to favour the spread of disease. Starting between the digits, infection spreads across the sole progressing up the wall of the hoof. Left untreated, it can lead to separation of the horn from the foot, resulting in a very lame sheep. Footrot has a characteristic foul-smelling discharge. It is highly contagious, so treat it as a whole flock problem.
  • Balled mud between the cleats – not a disease, but can cause pain and if left will damage the skin, leaving it open to infection.
  • Shelley Hoof (White Line Degeneration) – affects the area between the wall and sole of the foot, which can separate allowing soil and infection to enter; this condition may be hereditary, or the result of poor nutrition.
  • Toe Abscess – also affects the ‘white line’ from toe to heel, causes heat and acute lameness in the affected foot.
  • CODD (Contagious Ovine Digital Dermatitis) – causes severe lameness and is often hard to tell apart from footrot: infection starts at the coronary band and travels down the hoof, often causing total detachment.
  • Fibroma – this is a growth (often two) between the two digits that tends to grow as the sheep ages; they are benign but can rub and become infected.
  • Granuloma – often called ‘strawberry foot’, this can be caused by over-zealous trimming or injury, leaving proud flesh that will bleed and be difficult to heal.

Treating Active Disease – Antibiotic therapy

Scald and footrot are both bacterial diseases, and both will respond quickly to antibiotics if administered early in the disease and at the right dosage. Initially, a simple case of scald will respond well with the use of an antibiotic spray, such as Terramycin. However, if the disease has progressed to footrot, your vet will probably prescribe the use of an injectable antibiotic. This should be administered as early as possible, both to achieve the best possible outcome for the affected sheep, and also to prevent the spread of disease in the flock.

Treating Active Disease – Foot trimming

It’s almost universally agreed that excessive trimming the horn of the foot causes more problems than it solves! Not only is it virtually impossible to effectively sterilise foot shears between sheep, but in all other than the most skilful hands, trimming can adversely alter the natural foot shape. By all means trim off any grossly overgrown horn, but never cut so close as to make the foot bleed.

Pasture Management & Housing

Continual wet weather makes skin more prone to abrasion in muddy conditions, allowing the bacteria that cause scald and footrot to enter via the skin, so try to rotate pastures regularly to prevent them becoming poached. Remember that the two organisms that cause footrot can only live on pasture or bedding for up to 12 days, so leaving fields fallow for this period will help to break the cycle of disease. Similarly, when sheep are housed in close confinement, disease can spread rapidly, so use a sanitising powder frequently to reduce the risk.

Footbathing

Footbathing can play a valuable role in a foot-care programme, particularly when used to treat scald in lambs: they can then be turned out onto clean fields that have not carried sheep for the past 2 weeks. A zinc sulphate solution has the ability to penetrate the foot effectively, but always follow the manufacturer’s instructions closely, especially with regard to the length of time sheep must stand in the footbath. However, any chemical has its challenges for the smaller flock keeper, particularly regarding the use and disposal of toxic chemicals. There are now biodegradable, non-toxic products available that overcome both these problems, with the added benefit of adhering to the foot as a poultice for longer-lasting action and protection. (www.ecohoof.com).

Vaccination

Research using genetic markers has identified many different strains of the footrot organism, some more virulent than others. This makes it almost impossible to create a vaccine that will be universally effective. However, a vaccine does exist that is effective against the most common strains and will not only help limit existing disease but also prevent the spread of footrot by stimulating the sheep to produce antibodies; the makers claim 70% efficacy.

Culling Persistently Affected Sheep

If the same sheep continues to suffer from repeated bouts of lameness, or is chronically lame despite your very best attention, the recommendation is to cull the individual – otherwise it will provide a reservoir of disease and you will never be free of limping sheep. This may sound harsh, especially if the offending sheep has a good pedigree, but if the condition is hereditable, do you really want to perpetuate a susceptibility to lameness in the flock?

Breeding For Sound Feet

There is some evidence that susceptibility to foot disease may be hereditary. A useful starting point in your campaign to eliminate lameness in your flock is to keep meticulous records of every incidence of lameness in individual sheep; breed from those who remain sound, regardless of challenge. On the other hand, any that suffer repeated bouts of lameness are likely to be carriers of a virulent strain, so should not be bred from and preferably culled from the flock.

Footrot Resistant Breeds?

Anecdotally, some breeds of sheep have a greater resistance to footrot than others; with Romney and some of the hill breeds of sheep being less susceptible, and Suffolk sheep being more prone – though I suspect that there are many who would argue this point!

The Role of Nutrition

Much has been written about the significant benefits of supplementing zinc to help improve hoof condition and, as an added bonus, it is also beneficial to maintaining healthy skin, horn and wool!

Remember, footrot is a contagious disease so don’t bring it in with new sheep – even perfectly sound sheep may introduce a strain of disease that your flock is naïve to and which can have a devastating effect. FOOTBATH & QUARANTINE ALL INCOMING SHEEP in line with your Flock Health Plan, including your own sheep returning to your holding even if they haven’t been in contact with other sheep.

 


SGA-LogoThis article was originally written by Carole Youngs for
Practical Sheep, Goats & Alpacas Magazine.

 

 

 


The author gratefully acknowledges the invaluable instruction of veterinary surgeon and author Agnes Winter in getting to grips with lameness in her own flock.

 

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