Sheep lameness – Underlying issue to reduced performance?

Lameness in sheep

Lameness in sheep is a significant issue in flocks in Ireland. Lame sheep are a cost to any farm business due to the costs associated with treatment, control and loss of productivity.

When compared to a normal ewe, lame ewes can have:

  • 15% lower conception rate;
  • 20% decrease in body condition score;
  • 20% lower lambing percentage;
  • Lower ewe survival;
  • Poor lamb survival;
  • Reduced growth rate in lambs born to lame ewes;
  • Fewer lambs sold finished.

For effective treatment it is important that a correct diagnosis is made to identify the cause of lameness affecting each ewe. The three most common causes of lameness in sheep are bacterial infections of the skin and hoof, including: Scald, Footrot and Contagious Ovine Digital Dermatitis (CODD).

Misdiagnosis leads to mistreatment

Causes and symptoms of lameness in sheep

Bacteria that affect the skin and hoof are normally found in the digestive tract of animals. Virulent strains of Dichelobacter nodosus, the primary cause of Footrot in sheep, are maintained in the flock by both lame and recovered carrier sheep.

90% of lameness is caused by Scald and Footrot.

Scald

Scald is the term given to inflamed or reddened skin between the digits. The horn is usually unaffected. A damp environment predisposes sheep to developing scald.

Wet grass or moisture between the toes leads to an impairment of the defence properties of the skin which normally acts as a barrier to infection.

Bacteria which can be found on the surface of normal feet, Fusobacterium necrophorum, invade the skin when wet, resulting in damage. The interdigital skin can appear red and swollen or grey.

Lameness is usually mild and resolves when underfoot conditions improve. In the meantime, however, the damaged skin can allow entry of other potentially harmful bacteria such as the agent causing Footrot, Dichelobacter nodosus.

Footrot

Check out our NEW farmer brochure for all you need to know about Footrot in sheep! Click the arrows below to scroll through the pdf document.

Causes of Footrot in sheep

There are two forms of Footrot in sheep, benign and virulent. Benign Footrot is caused by certain strains of Dichelobacter nodosus that are less damaging than the strains that cause virulent Footrot.

The initial damage done to the skin is by Fusobacterium necrophorum resulting in Scald can allow the entry of bacteria that cause Footrot. This leads to further damage of the soft tissue underlying the hoof resulting in Footrot. Often more than one foot can be affected.

This image has an empty alt attribute; its file name is Footrot-article-Bovilis-1-edited.jpg

Virulent Footrot results in severe horn separation and the formation of a foul-smelling discharge.

Dichelobacter nodosus bacteria survives in the feet of lame sheep or recovered carrier animals. They can live in wet, muddy environments for approximately four days. During the grazing season, survival is enhanced by wet lush pastures. At housing, damp underfoot conditions improve transmission from either lame or recovered carrier animals to sound ewes.

Contagious Ovine Digital Dermatitis (CODD)

The exact cause of contagious ovine digital dermatitis is yet to be defined. However, Treponema sp. bacteria are frequently detected along with other microbes in cases of scald and footrot in sheep.

Ulcers are found at the coronary band, at the skin hoof boundary. Ulcers can also be found on the hoof wall. The condition differs from footrot in that there is a sudden onset of more severe lameness.

The majority of affected sheep become severely lame. In a clean flock, free of the bacteria causing CODD, purchasing infected sheep is the main route of entry.

The Five Point Plan Approach

The 5 Point Plan was developed using existing published science on sheep lameness, and practical experience from farmers who had achieved sustained low levels of lameness.

The 5 Point Plan has five action points that support the treatment of the animal in three different ways: Building resilience; reducing disease challenge; and establishing immunity.

Reducing the prevalence of lameness requires a long-term commitment to implementing all five points of the plan.

Talk to your vet for more information on creating an action plan for your flock!


Footrot vaccination a big success on Roscommon sheep farm

Vaccination as part of the strategy to control footrot has meant ewes with more milk, better lamb thrive and more lambs sold for Roscommon farmer Joseph Kennedy.

On the advice of his veterinary practitioner, Donal Flynn of All Creatures Veterinary Clinic, Joseph introduced vaccination as part of a strategic footrot control plan five years ago.

“I had a serious lameness problem. The labour and time involved in treating lame sheep was very high. Fertility in affected sheep wasn’t what it should be and I had regular problems with ewes with twin lamb disease,” said Joseph.

There has been a big reduction in lameness and the use of antibiotics to treat lame sheep. Overall, there has been a massive improvement in sheep productivity.

Joseph runs a flock of 80 ewes and 25 replacement ewe lambs at Weakfield, Co. Roscommon.

The commercial flock of Rouge/Texel crosses has scanned at an average of 2.2 in recent years. He is also a pure-bred Rouge breeder and there is strong local and regional demand for his rams.

Campaign

Joseph is participating in a national information and awareness campaign run by XLVets on the benefits of vaccination as part of a strategic plan to control footrot. The campaign is run in association with MSD Animal Health, manufacturers of the only vaccine licensed for the control of footrot.

Michael Keaveney, who farms at nearby Athleague, visited Joseph Kennedy’s farm with veterinary practitioner Donal Flynn to hear Joseph’s story on the benefits of vaccination.

Michael farms in partnership with his father Liam in the village of Roundforth. They have a flock of just over 200 ewes. Ewe lambs are reared on the farm and those not needed for replacements are sold as ewe hoggets for breeding.

Persistent problem

In common with a large number of sheep farmers, the Keaveneys have a big problem with lameness.

“We footbath regularly and we treat all serious cases with an injectable antibiotic and an antibiotic spray. But the problem is still persisting.

“We still have up to 10% of our sheep lame at any one time. Lamb thrive is not what it should be and the time and labour involved in treating lame sheep is huge,” said Michael.

Joseph Kennedy outlined his footrot control strategy including vaccination when the ewes are housed. While he got a response in the first year after vaccination, he said he could definitely see a big response after the second year.

The body condition of the ewes and the excellent lamb performance on the Kennedy farm were aspects that particularly impressed Michael Keaveney.

Last year, Joseph Kennedy had twin lambs fit for sale at 12-13 weeks of age and the small number of singles were fit at 10 weeks, evidence of the excellent performance achieved.

Discussion

Michael is now having a discussion with Donal Flynn on the benefits of vaccination as part of the footrot control strategy.

According to Donal, vaccination as part of a rigid control strategy will be cost effective.

“As well as lifting productivity and greatly reducing labour, vaccination also helps to reduce antibiotic use, a very important consideration in the current climate of concern about over- use of antibiotics.”

Footrot and scald the major causes

According to Donal Flynn, footrot and scald account for 90% of lameness in sheep. CODD (Contagious Ovine Digital Dermatitis) accounts for 5% and the remaining 5% is the result of other causes, including strawberry foot, shelly hoof and abscesses.

“The first step in tackling lameness is to correctly identify the cause of the problem. Misdiagnosis and wrong treatment can often make the problem worse.

“It will pay to get your vet to carry out a detailed inspection, identify the bugs and prescribe the most effective treatment and control strategy,” he stressed.

He said footrot which is caused by two different bacteria is highly infectious. Housing, collection yards, gateways, wet areas and supplementary feeding areas are heavy sources of infection.

Every time a lame sheep takes a step a deposit of the bacteria is left behind and other sheep are at risk of infection. Sheep do not acquire immunity to infection.

Impact

“A productive sheep flock should have a scanning rate of 2.0, a weaning rate of 1.75, a target liveweight gain in lambs of 300g/day and ewe mortality of less than 2%.

“Lameness plays havoc with these key performance indicators. It depresses fertility, leads to higher incidence of twin lamb disease and results in ewes with poor colostrum and lower milk yield.

“The end result is lower lamb performance and the risk of increased ewe and lamb mortality not to mention the heavy financial and labour costs of treating infected sheep.”

Five Point Footrot Control Plan

Donal Flynn said that farmers who have adopted the following five point footrot control plan have achieved good success in greatly reducing lameness and improving overall sheep health and performance.

“But it requires a change of mindset on the part of farmers and a 100% commitment to all aspects of the plan if good success in controlling lameness is to be achieved.”

  1. Treat All clinical cases should be treated promptly and effectively, including the use of an injectable antibiotic as well as a localised antibiotic spray. Paring of hooves should be kept to the absolute minimum. It can delay recovery and can even make the problem worse.
  2. Quarantine – All lame sheep should be isolated from the flock and treated accordingly. Keep bought-in sheep separate for at least 21 days.
  3. Avoid Spread – Regular and proper footbathing helps to reduce the spread of the disease. Spreading lime at gateways and around feed troughs can also be helpful.
  4. Cull – Some sheep are chronic carriers and will not respond to treatment. They are a continuing source of infection and should be culled. Donal recommends a two strike policy – if the sheep fails to respond to two treatments, cull it.
  5. Vaccinate – Donal stated that where footrot is affecting 5% of the flock, vaccination of the entire flock, in conjunction with the other four measures, is highly cost effective.

The best time to vaccinate is around a month before the start of the breeding season or before sheep are housed for the winter. Do not vaccinate within four weeks before and after lambing or within at least six weeks prior to shearing.”

“The primary vaccination course consists of two injections six weeks apart. In areas of constant disease challenge, re-vaccination should take place every six months.”