Lameness - What impact is it having on your flock?

Patricia Lynch discusses the costs associated with lame sheep, due to treatment expenses and production losses, effective management requires accurate identification, early intervention, and adherence to a five-point plan.

Lame sheep are costly residents to have on any farm not only due to the cost of treatment and control but most significantly the cost associated with the loss in production.  A welfare concern and a costly problem it negatively impacts pregnancy rates, ewe body condition score (BCS) and lamb growth rates. The three most common types of infectious lameness found are;

• Interdigital Dermatitis (Scald) - Sores between digits at the back of the foot, no smell from the sore and sheep become severely lame very quickly
• Footrot - Hoof horn lifting, foul smell, rotting hoof
• Contagious Ovine Digital Dermatitis (CODD) - Infection breaking out between the coronary band and hoof.

Interdigital Dermatitis (scald) and footrot are the most prevalent types of infectious lameness found on Irish farms, but most recently there has been a notable surge in the number of cases of CODD recorded. Already present in approximately half of all UK sheep flocks it is a serious emerging issue in Irish flocks and anecdotal evidence suggests that we are catching up fast with our neighbours.

To tackle this problem correctly, identification is key. Many farmers can be unsure as to what exactly they are treating.  They may presume that it is a bad case of footrot when they may in fact be dealing with CODD or may be purchasing costly antibiotics for footrot when indeed they only need a simple treatment for scald. For this reason it is vital to identify the type of lameness lesions present on the farm, and if needed turn over animals to get a good look at the hoof and if still unsure take a picture to show to your local vet for proper medical guidance.

Early intervention is also crucial to avoid it spreading rapidly through the flock. If left untreated, scald can lead to a more severe condition. Research has concluded that scald and footrot are part of the same disease spectrum and that scald should be considered as early-onset footrot, which if left untreated will progress in time to full footrot. Footrot can potentially lead to cases of CODD also, where CODD or its causative agents are already present on farm. Therefore, prompt and effective treatment of scald is essential to limiting and preventing cases of infectious lameness.

Five Point Plan

1. Cull – To build resilience within the flock cull persistent offenders. Records must be kept so that the same ewes are not treated on multiple occasions.
2. Avoid Spread – Both footrot and CODD are infectious diseases and can be spread from foot to foot via the ground, particularly in warm damp areas. The spread of infection can be reduced by using hydrated lime around handling and high-traffic areas at pasture. Keep troughs and minerals buckets moved around to avoid the accumulation of infection.
3. Treat – It is essential that all lame sheep are caught and treated effectively as disease spreads quickly so treat even mildly lame sheep as soon as possible. Rapid treatment helps stop the cycle of infection Catch – Inspect – Diagnose- Treat – Mark – Cull. It is important to note that farms with good handling/footbathing facilities generally have far fewer problems.
4. Quarantine – All incoming sheep should be inspected for signs of foot lesions, footbath on arrival and quarantined to avoid the introduction of a more virulent strains of footrot or CODD.
5. Vaccinate - Use of vaccination has been shown to lower the levels of footrot significantly by protecting individual sheep and lowering the level of challenge on the farm. Discuss a vaccination programme with your vet that best suits your farm.