Vaccinating for bluetongue prior to breeding “can give ultimate protection”, according to the Animal Health and Welfare Northern Ireland (AHWNI).
With breeding season now underway for many early spring calving herds, “the coming weeks may be the best time to vaccinate” (if calving later in spring), the AHWNI said.
As always, the best advice for farmers vaccinating cattle or sheep is to contact their private veterinary practitioner (PVP) for guidance on the best course of action.
Where appropriate, farmers should vaccinate breeding cattle against bluetongue to ensure their stock are protected in advance of the higher-risk summer months when warmer temperatures make virus replication possible within infected midges.
“For autumn calvers, vaccinating in mid-pregnancy should
still be effective in that there is little chance that the cattle could have already contracted the virus during the winter,” the NI-based animal health body said.
AHWNI also advised farmers breeding cows to “try to avoid vaccinating at very early-stage pregnancy, as stress can have a negative impact on foetus implantation”.
The animal health entity said that for best protection, vaccination should be completed “at least two weeks before bluetongue-infected midges arrive or are active on farm.
“Once temperatures are consecutively over 12°C, midges will become active.
“If average daily temperatures are above 15°C, then BTV, if present, will begin to replicate within midges and the virus will begin circulating.”
Risks of BTV outbreak in a herd or flock
According to AHWNI, the most severe cases of BTV reported in Europe were in sheep, with many fatalities recorded as a result of the disease.
“While this disease is still a high-risk to sheep in the UK and Ireland, so far in England the most severe cases have been reported in cattle,” according to the animal health entity.
“Specifically, there have been a number of ‘dummy’ calves identified.
“These are calves that have been born with brain malformations, leaving them with neurological problems, blindness, and no suckling instinct.
“In most cases, these need to be euthanised as they are unviable. Furthermore, there have been reported cases of increased barren
rates in cattle in herds infected with BTV.”
According to the Department of Agriculture, Food and the Marine (DAFM), there are three BTV3 vaccines approved for use in the EU, and widely used in BTV3-affected countries.
The pricing and supply of BTV3 vaccines is a commercial matter and the department has no role in setting or controlling prices, it also said.