Sheep Lameness

Causes of lameness and treatment

The most common causes of lameness are footrot and scald. These are both infectious diseases caused by Dichelobacter nodosus which means that just trimming lame sheep will not only fail to treat the problem but will also spread the bacteria between sheep.

Scald is the milder of the two diseases as it simply affects the skin in the interdigital space - causing redness, swelling and some white exudate. It can often resolve on its own especially if dry underfoot conditions are provided; otherwise spraying with oxytetracycline spray can assist healing.

Scald can progress to footrot if the horn becomes under-run, classically this occurs at the base of the interdigital cleft but if left to develop then it can spread up the wall and around the hoof. It causes severe lameness and weight loss as it is extremely painful. Footrot is associated with a foul-smelling odour and swelling. Footrot treatment also involves antibiotic spray combined with a long acting injection of oxytetracycline. Under no circumstances should the hoof be trimmed as it is highly contagious; if the sheep has particularly overgrown hooves the ends can be trimmed a week after antibiotic treatment. It is also important to separate any affected sheep to contain spread of disease.

Contagious Ovine Digital Dermatitis (CODD) can be difficult to differentiate from footrot so please consult us if you are unsure. Typically it affects the coronary band and the skin just above it but not the interdigital space. In severe cases the damage to the corium of hoof can lead to permanent problems with regrowth. CODD is most commonly brought onto farm by purchased sheep so strict quarantine protocols (described below) should be observed. Treatment is similar to that used for footrot.

Excessive trimming should be avoided as it can causes toe granulomas where a lump of tissue resembling a strawberry appears at the toe of the hoof, this creates and entry point for D.nodosus which will exacerbate the problem! Anti-inflammatories can help with the pain but often there is no cure the toe granuloma and the sheep may need to be culled.

Shelly hoof appears to occur if there is a nutritional imbalance and affects certain breeds or even breeding lines of sheep although the exact cause is currently unknown. The sole horn separates from the wall horn causes an air pocket with severity varying from a small area to loss of the whole hoof wall. Often sheep will only show signs of lameness once the air pocket fills up with soil or stones. This is one cause of lameness where conservative trimming can be used combined with clearing any debris out of the pocket. If your flock seems particularly prone to shelly hoof it would be prudent to assess their nutritional status as well as establishing if there is a particular family line that appears more prone to the condition.

Lameness control and prevention.

Sheep lameness is not only a welfare problem but can also have a severe economic impact which is estimated at around £5/lamb or £7/ewe. It is therefore prudent to follow our helpful tips to try and reduce the level of lameness in your flock:

• Examine lame sheep as soon as you see they are lame
• Identify the disease - if in doubt call us!
• Treat all footrot and CODD cases with tetracycline spray and tetracycline injection.
• Mark the affected leg
• Separate the affected sheep from the main flock and ideally re-examine in seven days.
• Avoid trimming if possible
• Cull sheep with more than two marked legs as they will be an infection risk to the rest of the flock.
• Ideally ear tag recovered sheep to identify repeat lameness and assist your culling policy

Consider footrot vaccination if this disease is a particular problem:

• Sheep are vaccinated twice 4-6 weeks apart followed by a booster before periods of risk. Timing of the booster varies between flocks and vaccination must be combined with an appropriate control programme
• If you show your sheep discuss alternatives to vaccination with us as it can cause lumps!
• Footbath your sheep every time they are gathered
• This is particularly useful for simple cases of scald in lambs or as an additional measure to attempt to prevent spread of footrot once lame sheep have been removed from the main flock.
• Footbathing is only effective for 36 hours so you must ensure sheep are turned out onto uncontaminated pasture. D. nodosus can survive for up to 10 days on the ground/handling facilities so the protection from the footbathing will run out long before the bacteria die!

Quarantine all replacements for three weeks. During this time ensure you:

• inspect all feet and treat all cases
• footbath before mixing with your own flock

Quarantining is also useful to identify and prevent any other diseases such as mites and worms!

Treating and controlling lameness requires good observation and rapid intervention. Please don’t hesitate to get in touch if you have any concerns about the level or type of lameness affecting your flock.