Mayo sheep farmer vaccinates against toxoplasmosis and enzootic abortion
“Two years ago, we had a couple of ewes aborting. I was worried that I would lose more lambs. I talked to my vet and we decided to send five foetuses – a set of triplets and a set of twins – to the laboratory in Sligo. The results showed they were positive to both toxoplasmosis and enzootic abortion.
“My vet recommended vaccination as part of the plan to tackle the problem. We vaccinated the entire breeding flock against both toxoplasmosis and enzootic abortion last autumn,” said Michael, who runs a flock of 70 Lleyn and Texel ewes at Eskeragh, Bellacorick.
He had no problems with abortion last spring. The ewes scanned at 1.98 and he has achieved a weaning rate of just under 1.8 lambs/ewe to the ram. All lambs, except ewe lambs held for replacements, are finished on the farm.
“Vaccination has been a great success. It has given me great peace of mind. I have a good flock. It’s vital that I fully control what’s inside the farm gate.
“I have no control over price but I do have control over the health and productivity of the flock,” said Michael who also operates a rigid vaccination programme against pasteurella pneumonia and clostridial diseases.
Lambs over three weeks are given a primary shot of Heptavac-P Plus followed by a booster four to six weeks later. This gives immunity for up to 12 months. The cost of vaccinating 100 lambs is equivalent to the loss of just one.
Ewes are vaccinated with Heptavac-P Plus four to six weeks before lambing. This ensures that their colostrum has the antibodies that protect lambs against disease in the critical first weeks of life.
Heptavac-P Plus is the only vaccine that protects against pasteurella pneumonia (caused by strains of Mannheimia haemolytica and Pasteurella trehalosi) and seven of the most important clostridial diseases – pulpy kidney, tetanus, blackleg, lamb dysentery, braxy, black disease and struck.
Toxoplasmosis, caused by a microscopic parasite Toxoplasma gondii (T. gondii), is most commonly caused by contaminated cat faeces in feed, bedding or manure or directly on to pasture.
“A single cat dropping can contain enough eggs to infect more than 5,000 ewes. It takes only one brief visit from a cat to contaminate the farmyard or pasture and almost 75% of ewes are believed to come in contact with T. gondii during their lifetime,” according to veterinary practitioner Sharon Magnier.
She added that vaccination is the only way to effectively build uniform immunity to toxoplasmosis in the flock.
“Where the risk of infection is high on a heavily contaminated farm populated with previously unexposed sheep, initial whole-flock vaccination is cost effective. As each situation is different, farmers should consult their vet about the most effective vaccination strategy for their flock,” advised Sharon, who is a veterinary advisor with MSD Animal Health.
Enzootic abortion (EAE), caused by a bacteria-type organism called Chlamydophila abortus, can result in 30% of sheep aborting. It is usually caused by infected bought-in replacements, but it can also be spread by wildlife carrying infected placentae from farm to farm.
It is highly infectious and organisms are passed from ewe to ewe in infected afterbirth, on new lambs and in vaginal discharges for up to three weeks after lambing. Lambs can also be born already infected from mothers carrying the disease.
“When a ewe aborts she sheds large numbers of organisms, which can infect any in-contact ewe or lamb. While ewes that aborted often continue to have a normal lambing in subsequent years, they are carriers of the disease and may still shed organisms resulting in infection of other sheep and lambs.
“Vaccination will effectively reduce the risk of enzootic abortion as part of a flock health plan. Because there is no test to identify latently infected sheep, it is important to vaccinate all breeding sheep in the first year. After that, only replacements need to be vaccinated,” advised Sharon Magnier.
A qualified carpenter, Michael Rowland worked in the building industry, including a spell in Dublin, before taking over the family farm in 2008 when his father Fergus passed away. He completed the Teagasc 180-hour training course at Mountbellew Agricultural College.
His building skills came in very handy when he and his wife Kathy built their own home. They were building the house when the outbreak of abortion occurred, which he said added further to the stress. The couple and their two-and-a-half-year-old son Seán recently moved into their new home.
They also run a herd of 14 suckler cows, selling the progeny as weanlings or stores. He built a sheep shed three years ago. Fergus, who bought the farm following his return from England in the 1970s, built a slatted cattle shed in 1980.
Michael combines farming with a job as supervisor on the Rural Social Scheme. Kathy also works outside the home.
“Vaccinating against the major disease threats is absolutely crucial for someone like me who also works outside the farm. It gives me the security of knowing that I am covered against the main risks,” he said.
The separate vaccines for toxoplasmosis and enzootic abortion (EAE) can be given to breeding ewes and lambs (from five months of age) prior to the breeding season. When using both vaccines, vaccination must be completed at least four weeks before sheep go to the ram.
The two vaccines can be administered at the same time, but not mixed, and must be given in separate injection sites. Due to the long lasting immunity induced by both of these vaccines, generally just one shot of each vaccine is required during the lifetime of the ewe*.
*Immunity against enzootic abortion is maintained for at least three years after vaccination and immunity to toxoplasmosis post-vaccination is maintained for two years and it is boosted by natural exposure to the parasite.