CODD present on 49% of Irish sheep farms – national survey

A costly infectious lameness causing disease of sheep, CODD or Contagious Ovine Digital Dermatitis, is present on 49% of Irish sheep farms.

That’s according to Jake Delaney, Teagasc Walsh Scholar, who addressed the Teagasc National Sheep Conference, today, June 18 in the Shearwater Hotel, Ballinasloe, where he shared key findings from a national study on lameness through his presentation titled: Understanding Lameness in Sheep Flocks; Causes Management, and Production Effects.

A two-part study completed in conjunction with Teagasc and UCD, it involved a farm lameness survey – unearthing the causes and practices associated with infectious lameness on Irish sheep farms – and a production impact study on eight farms enrolled in the Teagasc BETTER Sheep Farm Programme.

Through the survey element, Jake Delaney explained, data from 400 farms was captured in relation to the management, treatment choices and the ability of Irish farmers to recognise the causes of infectious lameness on their farms. Meanwhile, the production study encompassed 3,500 ewe and >2,000 lamb records across the farms involved.

“From our national lameness study, we found that the prevalence of infectious lameness nationally was 6%, with interdigital dermatitis (scald) the highest burden at 95% reported on farms. Worryingly from an animal welfare, cost and production perspective, 49% of farmers reported incidents of CODD,” Jake Delaney explained.

Additionally, Jake Delaney discussed the performance impacts from the presence of infectious lameness at farm level: “From our on-farm research, we found that lamb growth rates slow significantly when lameness is present. Lame lambs gain 10g/day less than non-lame lambs, although small daily, it results in an extra 7 days to slaughter, whereas lameness increases the proportion of ewes below a body condition score of 3 at both mating and mid-pregnancy.”

Understanding lameness causes

It’s critical that farmers understand what’s causing infectious lameness on their farms, Jake Delaney added, noting that different treatment options are required for each disease to prevent performance impacts occurring at farm level. Jake also outlined the key differences between the three main causes of infectious lameness:

• Scald (Interdigital Dermatitis) is caused by the bacterium nodosus and is seen as red, inflamed skin between the claws, often with a white discharge. It is highly contagious and can spread rapidly through a flock, particularly where skin has been damaged by small abrasions.
• Footrot is also caused by nodosus and may follow or occur alongside scald. It is typically associated with foul-smelling discharge and infection tracking under the hoof. Over time, hooves may become overgrown or misshapen.
• CODD usually begins at the coronary band, where erosion/ulceration with or without hair loss may be visible. In severe cases, one or both hoof capsules may loosen or detach. It is often mistaken for severe footrot, but foot-bathing is ineffective against CODD.

“Timing is of the essence when it comes to lameness control at farm level,” Jake Delaney added, “early identification and treatment of scald through appropriate footbathing will prevent progression to footrot and potentially CODD. Our studies have shown a significant likelihood for increased lameness prevalence when treatment is delayed by one week.”

“Scald is generally quick and easy to treat if detected early, while footrot is more difficult and time-consuming. CODD is harder again and can be expensive to treat. Prompt treatment and isolation of lame sheep is vital to both minimise the potential welfare and limit disease progression and spread,” Jake Delaney added.

Treatment

Also discussed were the treatment options available, with Jake Delaney noting that foot-bathing is appropriate for curing mild cases of scald and can complement antibiotic treatments when tackling footrot. However, he urged those in attendance to stop trimming hooves when it comes to treating footrot.

“53% of our survey respondents reported to trim hooves of footrot diseased sheep. However, our studies have shown a significant increased lameness prevalence when trimming to treat infectious lameness as routine treatment leads to increased lameness prevalence, time to cure, secondary infection risk and disease risk.”

Purchasing habits

The survey also revealed purchasing habits of Irish sheep farmers when it comes to replacement strategies. Almost half of surveyed farmers purchased replacement breeding females, yet 19% did not isolate bought-in stock and 63% isolated for less than one month.

“This creates a route for introducing new diseases, including CODD, on to farms. Follow effective quarantine measures, if you don’t have infectious lameness on your farm, don’t bring it in.”

For further insights, Jake Delaney’s full presentation to the National Sheep Conference will be available to view on the Teagasc website shortly.