Ewes should be vaccinated four-to-six weeks before lambing – Department vet
Vaccination is the most effective way to control both pasteurella and clostridial diseases in sheep, according to the Department of Agriculture’s Veterinary Surgeon William Fitzgerald.
Fitzgerald recommended that ewes should be vaccinated four-to-six weeks prior to lambing, as this boosts the level of antibodies present in their colostrum or first milk.
“Colostrum is the main source of antibodies for the new-born lamb.
“Lambs should receive adequate quantities of good quality colostrum within the first two hours of birth. The sooner the lamb gets the colostrum, the more benefit it will get from it,” he said.
Speaking at the Teagasc National Sheep Conference in Co. Wexford, he said that all lambs should receive their first vaccination at three weeks of age.
He also said that lambs should receive a booster shot four-to-six weeks later.
“It is very important to give the lamb a second shot. But unfortunately, some farmers don’t and when they get caught with a disease outbreak it costs a lot of money,” he said.
He also said that vaccines should be handled correctly as they are biological agents.
“Think of a vaccine like a carton of milk, you wouldn’t leave milk on the dashboard of a car for three or four days.”
Farmers should use vaccines that cover as many diseases as possible, but they must ensure that the give the correct dose, he said.
Diseases affecting ewes and lambs
Pulpy kidney is the most common clostridial disease encountered in the Regional Veterinary Labs, he said, with 42 confirmed cases in 2014.
It is commonly identified in fast-growing lambs, typically over one month of age that are consuming high concentrate diets, or sucking ewes.
“Losses in the flock often coincide with a sudden change in feed or an increase in the plane of nutrition,” Fitzgerald said.
He said that in most cases the sheep is found dead in the field, but in very rare occasions the affected sheep may have diarrohea.
Black disease is another common clostridial disease found in sheep in Ireland, he said.
It occurs in tandem with a liver fluke infestation. Sudden death in unvaccinated grazing animals is often the hallmark trait of this disease, he said.
Immature liver fluke cause quite a bit of damage passing through the liver.
“The bacteria is picked up from the soil and they multiply in the damaged areas of the liver, where they produce a powerful toxin which kills the sheep.”
Braxy tends to occur in either adult or yearling sheep. Typically it occurs during the winter and spring time when there is ground frost, Fitzgerald said.
“The frost covered grass causes the lining of the stomach to die and the clostridial bacteria attack the damaged tissue,” he said.
However, he also said that in recent years the disease has become more common in young lambs aged between three-to-10 weeks and finishing lambs of six-to-12 months of age.
“Pasteurellosis is an infection caused by the bacteria commonly found on the tonsils of healthy sheep. There were 87 confirmed case of this infection in 2015,” he said.
The disease occurs when sheep are stressed, as a result of excessive heat, over crowding, exposure to inclement weather or poor ventilation.
The disease can present in three ways:
- Blood poising
- Severe mastitis in ewes
“Sheep affected with the disease have very high fevers are very listless and are often found dead,” he said.
He also said that when the disease has been identified in a live sheep, the treatment time is very short as the bacteria replicate in the lungs and enter the bloodstream where they release a toxin.
Sheep that present with clinical signs are usually very ill and the success rate of treatment is very low.