Easy does it – how to keep coccidiosis at bay
Careful management can reduce the threat
Jeremy Hunt reports
FEEDING a creep ration with coccidiostat needs careful management to allow lambs to develop immunity to the parasite without developing the clinical disease.
Janet Catchpole, senior scientific officer at the Central Veterinary Laboratory in Surrey, says that stifling an early coccidiosis challenge through treated creep feed may prevent young lambs developing their own immunity.
Although not a view held by the CVL, it has been suggested that rations fed to in-lamb ewes should contain a coccidiostat to boost immunity in the developing foetus. Other schools of thought have centred on the best time to introduce medicated creep feed and questioned how long it should be offered to lambs.
"Sheep farmers should not assume that providing creep feed containing a coccidiostat from the start the most effective method of control," says Miss Catchpole.
She does not believe that diets of pregnant ewes should contain coccidiostat. "Ewes will produce from 100-1000g of infected oocytes a 1g of faeces. It is a low level of contamination, and one which new-born lambs need to be exposed to in the first two weeks of life to enable them to build up immunity.
"Adequate colostrum intake should provide lambs with the ability to cope with the initial challenge from parasites – within the first 10-14 days – without showing clinical signs of infection. High standards of management and husbandry, and the use of ample amounts of straw to keep pens clean and dry are equally important in reducing coccidiosis.
"There are 11 forms of the parasite which can infect sheep, though only two lead to clinical disease. However, there is a benefit to later-life immunity if young lambs are exposed to infection in the first 10 days of life."
Lambs fed a medicated creep ration may have their own level of immunity undermined – all too often the cause of coccidiosis seen in lambs at a later stage. And it should be noted that the disease can only be spread via faeces, although dung does not become infectious for up to 48 hours after being passed – hence the benefits gained by regular bedding with clean straw.
Farmers lambing ewes indoors and keeping lambs inside for finishing in early spring should seek the advice of both their vet and their feed compounder when assessing coccidiosis prevention measures. Although much will depend on the level of incidence of the disease in previous years, it may be more effective to introduce medicated feed at around three weeks old and to offer it for a limited period.
And although widely considered a problem of lambs born and reared indoors, coccidiosis among grass-reared lambs can also be severe. Official CVL figures have shown that 20-25% of flocks with lambs at grass suffer from coccidiosis.
"Insufficient colostrum will increase susceptibility, but moving ewes and lambs to different pastures and mixing batches can pose a big risk.
"If lambing is spread over several weeks it is not uncommon to see two-week-old lambs grazing alongside others which may be six weeks old. These younger lambs are facing a high risk of infection from their older flock mates. Lamb groups should not contain animals which differ in age more than two weeks."
On a farm with a previous history of coccidiosis, if 5-10% of lambs are scouring and showing clinical signs of the parasite, it may be advisable to treat the entire flock, either with an injectable or drench medication.
Severe scouring in lambs at three to six weeks old can be disastrous if action is not taken immediately. There is no time to wait for dung sample analysis. A five to six day delay may lead to heavy losses so treatment must be instant.
It may be that odd cases will reappear again after about two weeks in which case individual treatments should be carried out, says Miss Catchpole.n
Allowing lambs to build up immunity within the first 10 days of life, and careful use of medicated creep feed will minimise coccidiosis losses, says CVLs Janet Catchpole.
• Bed adequately with clean straw.
• Ensure good colostrum intake.
• Seek advice on when to introduce coccidiostat.
• Keep lamb groups to those born within two weeks of each other.
Painkillers can be costly but worthwhile…
By Emma Penny
PAINKILLERS can help make lambing ewes more comfortable and aid mothering.
Currently, they are under-used and under-valued by shepherds, says Dr Elspeth Scott, of the Moredun Foundation, Edinburgh. "Painkillers can be expensive, but theyre likely to be used only in a few cases. And from a welfare point of view they are worthwhile if its been a hard lambing."
And in cases where ewes are in pain after lambing it may be difficult to get colostrum into lambs; milking ewes out and stomach tubing lambs adds to the workload.
"If the ewe is not up and eating after lambing shes likely to take longer to recover, and theres the likelihood of further complications."
Dr Scott admits that it is difficult to tell whether ewes are in pain, but she goes by the premise that if in doubt give the painkiller. "Also, where lambing has been assisted, even where you have worn gloves, its best to give an antibiotic."
The options for painkillers, however, are limited at present to either local anaesthetics given as an epidural, which must be given by a vet, or non-steroidal, anti-inflammatory drugs, only one of which can be given by shepherds.
"An epidural is injected into the spinal cord by the vet after lambing. The difficulty is reducing the pain in the vulva without the ewe losing the use of her back legs, which can make suckling difficult, particularly when lambs need colostrum quickly."
The only non-steroidal, anti-inflammatory drug which can be used by producers is Finadyne. It is not licensed for sheep, but can be used.
"It gives about 24 hours pain relief. But, its rather like Asprin, in that it prevents clotting, so is less useful where theres a risk of haemorrhage, but thats rare."
Dr Scott cautions that Finadyne shouldnt be used before the ewe has lambed because it prevents formation of prostaglandins which are needed for contractions. *
• Limited options.
• Reduces ewe stress.