Vets are urging farmers to remember to vaccinate replacements heifers due to concerns about gaps in disease control.
Often replacement heifers can get overlooked for vaccines and secondary doses for diseases such as BVD and leptospirosis when the main herd is treated, believes vet James Allcock, Lambert, Leonard and May, Shropshire.
However, it’s imperative cattle receive a primary dose to “familiarise” a heifer’s immune system so when it receives its single booster the following year it will recognise it immediately and the body can mount a prompt and effective immune response.
“When an animal hasn’t received a primary course, any further doses of vaccine won’t work, so it’s a waste of time and money and there’s an increased risk of disease,” says Mr Allcock.
“While vaccination protocols may be in place they aren’t always followed as rigidly as they should be, because it’s difficult making sure every heifer is jabbed at the right time when they are so many other things going on. It can be a real brainbuster unless there’s a process in place to act as a constant reminder.”
Vaccinating a whole herd of cows on a particular day gets the job done in one go, but making sure all the maiden heifers are jabbed before service takes more of an effort, says Mr Allcock.
“This means some inevitably get missed and many don’t get the important second dose. It can be well over a year before they are vaccinated again as part of the routine herd vaccination. So there is a weak link created among those animals that aren’t protected,” he adds.
Many vaccines protect against fertility losses or, in the case of BVD vaccine, actually protect the calf from becoming persistently infected with the virus. Most vaccines take about four weeks to become effective, hence the need to leave at least four weeks after the primary course before breeding begins.
Best practice advice is to identify heifers that need to start their primary vaccination course – everything from eight to thirteen months of age on that date – and will be served within the following six months. Eight months is the youngest age heifers can be vaccinated against BVD.
“Anyone serving significant numbers of heifers before fifteen months old should speak to a vet. They will need a course of two doses of BVD and leptospirosis vaccine according to the manufacturers’ recommendations.
“Record identification of the youngest animal started on the programme for easy reference of where to start from next time. And when the rest of the herd receives their boosters, don’t forget the heifer replacements that have received a primary course but haven’t calved. The rule for the herd booster under this system is to give a booster to any animal 14 months of age or older,” says Mr Allcock.
“We’re worried that as herd size increases and we have more diseases to vaccinate against, we may not actually be achieving the best protection available through vaccination because of “gaps” in the policy for vaccinating replacements.”
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