Sheep feet through winter

01 Jul 2022

Tablelands Telegraph - July 2022

How to minimise health risks

With the wet weather expected to continue, it’s important for the health of your sheep that you minimise lameness in your flock.

Firstly, you need to understand the common causes of lameness and then what you can do to prevent these diseases.

Common causes of lameness

Wet pastures, mud puddles and heavily pregnant ewes can be a bad combination. Lameness in sheep can be caused by a multitude of issues but the most common ones we see through winter is foot abscess, and Ovine Interdigital Dermatitis, or “scald”.

Foot abscess is where the infection enters the tissues underneath the skin, possibly into the joint spaces in the toes. This causes a swelling that is painful, leading to lameness. In particularly wet seasons, it is impossible to completely eliminate foot abscess, prompt treatment is important in these seasons, often antibiotics are used to treat and prevent further infection.

Ovine interdigital dermatitis (OID) is a skin infection that occurs between the claws of the feet. Standing in moist conditions softens the skin, the same way our skin softens in a bath. This increases the risk of small cuts in the skin that subsequently become infected causing OID.

OID is commonly confused with benign footrot (BFR). BFR is an important disease to manage as it can have significant production losses. It is caused by a strain of a bacteria that causes damage to the tissues in between the toes. Unlike virulent footrot it does not continue across the sole, often being confined to the space between the toes.

The more severe case of footrot is virulent footrot which causes lameness through eroding the sole of the hoof. If can cause a significant proportion of the flock to show lameness, with significant negative production effects. Footrot is notifiable in NSW, requiring producers to contact LLS if they suspect they may have virulent footrot.

What can you do to prevent these diseases?

Grazing sheep in dry (or drier) paddocks can keep the skin dry, minimising the risk of infection. Elevated, sloping, sandy or rocky paddocks are ideal. Managing ewe body condition score to they are not over fat (keeping them around BCS 3-4/5) can help by reducing the stress on the foot, reducing the stretch of the skin between the toes and risk of trauma opening the skin up.

Preventative foot bathing can be helpful for OID, Scald or footrot. This dries the skin, providing some protection from infection. For best efficacy, standing sheep for 20minutes then holding them on boards is recommended. If that’s not possible, holding them somewhere dry is beneficial to allow the footbath chemical time to work. Running them through a foot bath may be beneficial, but the effect is significantly reduced compared to standing them in it. Some producers will let a race out and stand the sheep in the bath whilst the fill and treat the next race. The most commonly used chemical is 10-20% Zinc sulphate.

If you are concerned about lameness in your flock please contact your local vet or one of our District Vets.