Post Weaning Scours:

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Post Weaning Scours
Scouring in young pigs in the immediate post-weaning period has long been recognised as a significant problem as NADIS reporting veterinary surgeons routinely record problems on farms of this nature writes Mark Wright BVSc, DPM, MRCVS in the June NADIS BPEX Commentary.

 

There are a wide range of microbial agents implicated in the condition but the most common is usually considered to be E-coli bacterial infection. Despite the very widespread use of zinc oxide in baby piglet feed, post weaning scour continues to be reported in approximately 1% of all pigs seen by veterinary surgeons undertaking NADIS surveillance.

In most cases colonisation of the gut takes place early in life and E-coli form part of the ‘normal’ gut flora. Changes to intestinal structure as a result of the weaning process including reaction to withdrawal of liquid milk diet and replacement with creep/starter rations, coupled with other environmental factors such as hygiene standards and chilling allow certain strains to proliferate. These are capable of producing toxins which lead to scour. However, the development of gut enzymes at weaning is such that pigs may struggle to digest complex molecules (starches, vegetable proteins) and in these times of challenging economics the temptation to use cheaper diets (usually containing less cooked cereals and less animal protein) can potentially lead to scour problems. The younger the pigs are at weaning the greater the risk.

NADIS records over the last 12 months reveal a number of features relating to post weaning scour (all causes) that may assist long term control strategies.

Scour prevalence declined in the summer months of 2007 before rising more than 50% in the autumn (Graph 1). The fact that prevalence has declined again in winter suggests that temperatures alone may not be the most significant factor. Typically, we consider autumn (and spring) to have the greatest variation in temperature which may be significant although they would require verification with meteorological data for the last 12 months.





Graphs 2 and 3 suggest there may be more scour in herds containing finishing pigs than those selling weaners and that breeding herds of ‘average’ herd size (100 – 300 sows) are over represented in terms of post weaning scour in the progeny.

represented in terms of post weaning scour in the progeny.








Graph 4 may be interpreted as representing the significance of hygiene. Prevalence of scour in straw based system post weaning is more than twice that in slatted accommodation, whilst batch system, where all in all out management is more likely to be practiced, sees lower levels of scour than systems operating by continuous flow. Furthermore, pigs kept in or derived from outdoor system appear to reveal more than twice the levels of scour than those indoors. There may however be a cross–correlation here with straw v slatted accommodation.


Reports reveal a wide variation in the prevalence of post weaning scour by region (Graph 5) with the lowest levels seen in the traditionally ‘intensive’ North East (where slatted weaning accommodation is favoured) whereas East Anglia – an area containing more outdoor herds and tending to favour straw based accommodation – reports four times higher prevalence.
Post weaning scour - which can be associated with E-coli, Salmonella, Rotavirus and a wide rang other microbes – is a consistent challenge to UK pig farmers with NADIS observational data highlighting some of the more significant potential risk factors.

June 2008