Pasteurella pneumonia

Farm vet David Charles discusses pasteurella pneumonia. Do you know what it is and how best to protect your flock?

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As the evenings start to draw in, some of you will have finished tupping, whilst others prepare to start on bonfire night (in with a bang and all that…).
Typically, this is the quarter where we see less of our sheep clients but that doesn’t mean we’re not here should you need us either in hours pre-booked, or with our two vets on call anytime out of hours (yes, even on Christmas Day!)

Pasteurella pneumonia prays on the poorly protected!

For most people pasteurella vaccination is something thought about in the early months of the year, either as a pre-lambing booster for breeding ewes or as a primary course for lambs when the maternally derived immunity gained from the colostrum wears off. However, as we enter the Autumn, those of you who keep store lambs may want to think about pasteurella prevention once more. A study over the late 2010’s was carried out and found there to be a repeatable seasonal spike as we enter the Autumn months due to the increase in risk factors and environmental pressures.

Typically, pasteurella manifests itself through pneumonia outbreaks with as high as 25% mortality within the flock, although we do also see it present as septicaemia with common signs being sudden death in the flock or lots of moribund animals with a high percentage affected.

Pasteurella pneumonia isn’t just a problem due to the clinical cases or deaths that occur; sub clinical cases will also occur in flocks that aren’t protected causing reduction in growth rates of both ewes, store lambs and lambs yet to be born. It also has high financial implications for all the reasons mentioned as well as the increased treatment and personnel costs.

With many of these pressures relating to the weather, most of them are outside of our control, and therefore the best way to minimise losses or reduction in performance due to pasteurellosis in  October/November/December is to give store lambs, bought in or home reared, a third dose of pasteurella vaccine in early Autumn as the pasteurella component of HeptavacP doesn’t give a full twelve months of protection; whereas it does give a full twelve months protection against the clostridial bacteria.
Therefore, it is okay to give a booster vaccine of Ovipast or HeptavacP to store lambs that have had a primary course earlier in the year.

Results of the APHA Thin Ewe Project

You may remember towards the end of 2020 we offered free euthanasia and post mortem examination of three thin ewes from your flock as part of a project run by the APHA to screen for the common ‘iceberg’/ ‘thin ewe’ diseases and their prevalence.

The major ‘iceberg’ diseases tested for were:
– Johne’s disease
– Maedi Visna (MV)
– Caseous Lymphadenitis (CLA)
– Ovine Pulmonary Adenocarcinoma (OPA)
– Border Disease

In August (1) the results were published from the 75 flocks enrolled in the scheme. 31 of these flocks tested positive for at least one of the iceberg diseases, although no border disease was found. 7% of flocks had more than one iceberg disease detected on post mortem examination.

The most common condition found through the scheme was chronic endoparasitism (worms) as the cause of ill thrift, followed by Johne’s disease and lungworm.

The prevalence of maedi visna was relatively low (3%), fitting with the fact that there are two control schemes in the form of MV monitored and MV accredited.

If you suffer from a higher than usual amount of thin ewes or are culling out a lot of ewes based on poor condition, it could well be worth having us perform a post mortem examination on one of the cull ewes to screen your flock for disease and inform any control or prevention strategies.

(1. https://bvajournals.onlinelibrary.wiley.com/doi/10.1002/vetr.800)

If you would like to discuss flock health further, contact us today

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