Advice on vaccination protocols for dairy herds

Failure to adhere to vaccine protocols could prove to be an expensive mistake for dairy farms.

Vet Sophie Prichard says such herds will not have optimal protection against disease and the vaccine manufacturer is unlikely to provide support if a breakdown occurs.

“If [animals are] vaccinated according to recommended datasheet protocol and a disease outbreak occurs, manufacturers may agree to provide assistance, with further testing and investigation of management factors that can contribute to overwhelming infection pressure at times,” she explains.

See also: 5 ways to improve biosecurity on dairy farms

Adhering to protocols is key to making the financial and labour investment involved in vaccinating a herd worthwhile.

In the case of an annual vaccine, for example, letting the timings slip and vaccinating at 15 months instead of the required 12 will leave a gap in cover and expose animals to a disease risk.

“Make sure that your vaccination protocols are watertight: if something is worth doing, it’s worth doing properly,” recommends Sophie, of Fenton Vets, Pembrokeshire.

Bovine viral diarrhoea

Bovine viral diarrhoea (BVD) is a good example where correct timing of vaccination is critical to provide protection against the production of persistently infected (PI) calves – the driving force behind the disease.

And timing will depend on the type of vaccine used.

Modified live BVD vaccine needs to be given at least three weeks before insemination to give protection to the foetus.

It requires a single dose to provide immunity, with an annual booster as ongoing protection for future pregnancies.

Inactivated BVD vaccines are different, says Sophie.

These require two doses, four weeks apart, with the second dose at least four weeks prior to insemination to protect the foetus.

A booster should be given after six months and annually thereafter.

In Wales, the importance of getting the timing of vaccination for BVD right has increased since the launch of the BVDCymru scheme in July 2024.

This requires all farms to blood test a sample of unvaccinated youngstock to screen for the disease.

The test looks for antibodies to BVD, which will be present if the animal has been exposed to the virus and has mounted a natural immune response, orwhen the animal has been vaccinated.

“Making sure that you have a cohort of unvaccinated cattle between nine and 18 months old for the annual test may influence the age at which you start to vaccinate,” Sophie explains.

Annual health review

Which diseases a farm should vaccinate for will depend on its individual requirements.

Factors such as disease history, whether the herd is closed, farm management, milk contracts and contracts with calf buyers often influence those decisions.

Sophie says reviewing how the disease status of a farm is monitored, and how best to protect against the threat posed by infectious disease, should be a part of every farm’s annual health review with their vet.

“Disease challenges continue to evolve, and there are vaccines available for many, but not all, of the diseases that can have a significant impact on both the welfare and production efficiency of dairy cows,” she says.

However, she points out that vaccination is just one component of maintaining good disease control.

Cow and calf nutrition, biosecurity, housing and environmental management and minimising stressors also play vital roles in keeping infection at bay.

Protocols for other key vaccinations

Sophie advises the following:

Infectious bovine rhinotracheitis

• Timing of vaccination Ahead of an individual farm’s risk period – for most holdings, this is winter housing.
• Type Live and inactivated vaccines are available.
• Number of doses Different vaccination schedules are recommended depending on a farm’s perceived risk level.
• Booster Farms that regularly buy animals in or have cows under a significant level of stress – for example, if they are high yielding, have suboptimal nutrition or there are other disease threats – would benefit from a live vaccine boosted every six months. This can initially be given intranasally to provide rapid immunity from four days after administration. Lower-risk farms may choose to boost annually.
• Other considerations Monitoring the success of the chosen vaccination protocol will allow the farm and its vet to tailor a schedule to provide best protection for the herd.

Leptospirosis

• Timing of vaccination Cows in grazing herds should be fully vaccinated before turnout as this is the highest risk period for disease transmission.
• Type Inactivated.
• Number of doses Two doses, four weeks apart.
• Booster An annual booster is required to maintain protection.
• Other considerations As well as being a cause of milk drop, infertility and abortion, leptospirosis is a zoonotic disease that can cause illness in people.

Salmonellosis

• Timing of vaccination Ahead of the main risk period, which is usually around calving.
• Type Inactivated vaccine containing the two most common strains that cause disease in cattle – Salmonella dublin and Salmonella typhimurium.
• Number of doses Dose depends on the age of the animal. Cattle over six months of age require two 5ml injections separated by an interval of three weeks. Pregnant cows that have not calved within eight weeks of the second dose should receive a further 5ml dose three or four weeks ahead of calving. Calves younger than six months but older than three weeks can be given two 2ml injections, three weeks apart. Significant levels of immunity cannot be expected until two weeks after the second dose of the primary vaccination course.
• Booster An annual booster is recommended and should be given a month before calving to optimise protection of the cow and calf.

Calf scour

• Timing of vaccination Between three months and three weeks prior to each calving.
• Type Inactivated.
• Number of doses A single dose given to dry cows. Different brands have different doses, either 2ml or 3ml, therefore it is very important to read the instructions supplied.
• Other considerations Vaccinating dry cows against rotavirus, coronavirus and E coli, the most common causes of calf scour, can be a valuable tool in reducing risk to young calves. Feeding of colostrum and transition milk must be optimised to gain the maximum benefit from these vaccines, as the protective antibodies produced by the cow in response to vaccination are transferred to the calf via the colostrum. Feeding appropriate volumes of high-quality, vaccine-enhanced colostrum and milk for seven days is advised.

Mycoplasma

• Timing of vaccination A new vaccine has been licensed to be given from one week of age to protect calves from respiratory disease caused by Mycoplasma bovis.
• Type Live.
• Number of doses Two doses, three weeks apart; this will give immunity for 12 days after completion of the primary course.
• Other considerations Use of antibiotics effective against this organism should be avoided for two weeks before and after vaccination.