NOAH vaccination guidelines – what do they mean for sheep vets?

In mid-2022 – without huge fanfare or parade – NOAH launched a document that has the potential to dramatically increase the livestock veterinarian’s arsenal against infectious disease: “Livestock vaccination: guideline for dairy, beef and sheep sectors” (Statham et al, 2022).

While the guidelines provide recommendations, and discuss vaccination and disease in all three of the named sectors (dairy, beef and sheep), this article will solely focus on the recommendations made in “Section 4: sheep”, alongside the benefits and implications that these may have for the ambulatory large animal practitioner.

For a long time, sheep vets have used the “Plan, prevent, protect” mantra when discussing infectious diseases with clients, and the livestock vaccination guidelines can play a big part in all three areas to aid in the reduction of disease spread and the protection of UK livestock.

Which vaccines are being recommended?

The publication categorises livestock vaccines by sector (dairy, beef or sheep) and then into NOAH Category One or NOAH Category Two.

Category One vaccinations are viewed as the highest priority vaccinations, with a critically important role in flocks. Essentially, NOAH’s stance is that Category One vaccines should be given as a default unless a flock-specific discussion has taken place between the client and their vet to justify not using them (which should be reviewed regularly).

Use of Category Two vaccinations, on the other hand, is viewed as ”gold standard” or “best practice”, but NOAH recommends a discussion between farmer and vet should be had to decide on their use and applicability to each particular group within a flock.

UK sheep diseases and vaccination categories are listed in Panel 1.

When to give each Category One vaccination

Category One vaccinations should be given as follows:

• Clostridial diseases –
  • Primary course of two injections four to six weeks apart, with the first not before three weeks of age.
  • Annual booster to ensure continual protection.
  • Pre-lambing booster four to six weeks pre-lambing (this can be the annual booster).
  • Don’t forget to vaccinate breeding and teaser rams at annual booster.
• Lameness: footrot –
  • Primary course of two doses four to six weeks apart for replacement youngstock and breeding adults.
  • Following primary course, adult sheep should receive a minimum of an annual booster.
  • Where required, an additional six-month booster can be given before risk periods (for example, housing or mixing with unvaccinated stock; NOAH, 2023a).
  • In some circumstances if a flock is entirely closed, has a prevalence of less than 2%, and exceptional adherence to the five-point plan and after veterinary consultation, it may be viewed that vaccination is not required (NOAH and Lovatt, 2022).
• Abortion: toxoplasmosis –
  • Single dose given a minimum of three weeks before mating offers at least two years of protection (Statham et al, 2022; NOAH, 2023b).
  • Older ewes may need re-vaccination in high-risk flocks; some older ewes may achieve natural immunity.
• Abortion: Chlamydia abortus (enzootic abortion of ewes; EAE) –
  • Single dose of a live attenuated vaccine a minimum of four weeks before first mating. Re-vaccinate older ewes (three to four years post-vaccination) where ongoing risk of exposure exists (for example, due to mixing with sheep of unknown status).
  • Or, two doses of an inactivated vaccine delivered three weeks apart, with the first dose at least five weeks before mating or AI (re-vaccination with a single dose annually; HIPRA, 2019).
  • In both cases, do not vaccinate ewe lambs under five months of age.
• Pasteurellosis: Pasteurella –
  • Primary course of two injections four to six weeks apart, with the first not before three weeks of age.
  • Minimum annual booster to ensure continual protection – evidence to now give an early autumn booster before the risk period (NOAH, 2023c).
  • Pre-lambing booster four to six weeks pre lambing (usually in a combined clostridial/Pasteurella vaccine).
  • Don’t forget to give booster vaccinations to breeding and teaser rams (minimum annually and definitely before autumn risk period).

What problems might we face?

Unfortunately, we have to discuss the elephant in the room: the recent supply (or lack thereof) of sheep vaccines since 2021.

In the past few years, it seems like every major sheep vaccine has had production or supply issues at some point, with some products being off the market for months either entirely or in certain sizes (the distinct lack of HeptavacP plus last spring comes to mind as a time when practitioners felt a lot of pressure from clients as they all looked to give their pre-lambing boosters).

On the positive side, one must acknowledge the fantastic advice and support offered by the territory managers and veterinary advisors at the pharmaceutical companies when shortages do come, with many often providing advice on alternative products or combinations of products if issues do arise.

Unfortunately, though, some products are without alternatives and a failure of supply can cause real issues, and leave entire flocks at risk of infectious disease outbreak. For many sheep vets, one of the concerns each year is when advising clients about vaccination against toxoplasmosis, with there only being one product that has a limited number of vials produced each week, a minimum time before mating it can be administered and a tremendously short shelf life.

Timing clients’ orders for when they are able to inject is essential.

Traditionally, vets have always been advised to recommend that clients “pre-book” their order for the week they want it as soon as possible, to get their allocation before the total amount produced that week is requested.

However, we saw in 2022 this system fail when all September slots were full and a production issue meant a period where no vaccine was produced, yet clients couldn’t just rebook on to the following week as that had already been pre-allocated; cue the usual case of vets having to telephone around other practices on the off chance they had clients order too much.

In this author’s opinion, if we want to really encourage and facilitate the uptake of these guidelines, and the almost blanket use of Category One vaccinations across the UK flock, we need better guarantees that the infrastructure, and reliable supply chain is there from the manufacturers and pharmaceutical companies to deal with an increased demand.

Farm assurance opportunities?

One way in which this guidance could see rapid uptake and increased penetration into the sector would be by having the use of Category One vaccines embedded into the “recommendations” or “requirements” of farm assurance schemes.

By mimicking what Red Tractor has done with pain relief and calf castrations (recommended in beef and required in dairy; Red Tractor, 2020), over the next couple of years, we could see a rapid uptake of Category One vaccine use, a national reduction in levels of infectious abortion and decreasing lameness prevalence (helping us catch up to the 2% target the industry had set for 2021; Farm Animal Welfare Committee, 2011; Best et al, 2020). However, it must be noted that this may reduce the engagement with the EAE accreditation scheme run by Scotland’s Rural College (SRUC) where EAE vaccine is not permitted (SRUC, 2020).

It will be interesting to monitor what happens with the dairy recommendations as to whether any of the milk buyers introduce criteria in their contracts around mandatory use of Category One vaccinations, as it is likely this may happen before voluntary schemes such as Red Tractor, or the Farm Assured Welsh Livestock Beef and Lamb Scheme take similar approaches.

How can we use this to engage clients?

When discussing this with practice colleagues in autumn 2022 and at the IVC Evidensia Farm Vets Congress in Edinburgh in September 2022, very few vets were aware of this resource, or using it to aid in discussions with their sheep farmers around infectious disease control and prevention.

With the Animal Health and Welfare Pathway now live, and potentially changing the way we are able to reach out to our less engaged sheep clients by offering £436 for a vet visit (Defra, 2022), flock health planning and disease testing, the launch of the NOAH guidelines is very timely, and a useful tool to discuss and highlight to clients.

Alternative routes for client engagement with the resources and vaccination protocol reviews could be client talks, Flock Health Club meetings and, during disease outbreak investigations throughout the spring (as we know that this is often when our engagement with sheep clients is at its highest) to stimulate year-round discussion, relationship and collaborative approach to reduce the challenge or risk of several key infectious diseases in our sheep flocks.

Conclusions

The author would strongly encourage every vet dealing with sheep (commercial, pedigree or smallholder) to download a copy of the NOAH Livestock Vaccination document, familiarise themselves with it, and use it as part of a structured discussion with clients around their infectious disease prevention and control strategy.

The impact we can have by recommending default use of Category One vaccines is vast – especially at a time when funded vet visits for flock health reviews are available and other initiatives such as client talks, discussion groups and farm walks are possible again.

Within the wider sector, this document could have huge beneficial implications on vaccination use if it is picked up by farm assurance organisations, and if the supply chain steadies out again to increase the ease at which farmers can access the vaccinations that are recommended.