Control plan for lameness in sheep

Lameness in sheep is a common and persistent disease and can occur at any time of year. Lame ewes, rams and lambs do not thrive, and treatment of lame sheep incurs a significant cost to the sheep farmer. Eamonn Dempsey, Teagasc advisor in Tralee, discusses further.

The key to controlling lameness is a proper diagnosis with the two main causes of lameness being scald and footrot. A scald is most likely the diagnosis if there is sores between the digits at the back of the foot, no smell and the sheep become severely lame very quickly. Outbreaks of scald are typically seen in lambs on pasture and among ewes housed on straw.

If the hoof horn is lifting, the hoof is rotting and foul smelling then it is most likely footrot. Footrot is a highly contagious disease and spreads more readily in warm, humid weather, outdoors and when sheep are housed.

Another cause of lameness in which farmers have become familiar with is Contagious Ovine Digital Dermatitis (CODD). CODD begins in lesions or ulcers in the coronary band. The infection starts small but can spread under the horn towards the toe and in severe cases the whole horn can fall off. As CODD can spread rapidly through the flock, a quick diagnosis is important to differentiate CODD from footrot.  Other causes of lameness include shelly hoof, white line abssess and toe granuloma. Once diagnosis is completed and the cause identified, treatment should begin immediately.

Scald can be treated using oxytetracycline aerosol spray or walking sheep through a 10% copper sulphate solution or 3% Formalin in a footbath. After foot bathing, allow sheep to stand in a dry area, so solution can dry into the feet. For treatment of footrot - isolate badly affected sheep and consider paring (routine paring is not recommended), spraying with antibiotics or in severe cases a long acting antibiotic injection.

Ideally sheep should be foot-bathed every time they are in for handling/drafting, then separate lame sheep and lambs for further treatment. The aim should be to keep the number of lame sheep at any one time below 5%. It is important to identify and cull chronically infected sheep, as they and their offspring may be genetically more susceptible to lameness and be an ongoing source of infection to other animals.

Quarantine all purchased sheep for 28 days on arrival to avoid the introduction of a different and perhaps more virulent strain of footrot.  It is important to maintain roadways and update sheep handling facilities as flocks with good handling/footbathing facilities in general have far fewer problems. Other general measures to help reduce the incidence of lameness include rotational grazing, moving troughs, lime at gateways and avoid high stocking densities in lambing sheds. A flock health plan to control lameness and manage sheep health should be updated annually to include relevant veterinary and technical advice.