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Ear Necrosis - know your enemy

Ear Necrosis - know your enemy

Ear necrosis is a relatively new problem in pig production that has developed over the last 20 years but in particular during the last decade, Michael McKeon tells us how we can manage it.

In order to control / reduce / eliminate the problem, we need to ‘know thy enemy’ of how it originates and develops. In simple terms, ear necrosis appears to be a bacterial infection that enters the pig and travels to the extremities of the pig’s body (tail or ear tips) where there is little blood circulation. At these extremities the bacteria multiplies and causes the tissue/flesh to die (necrosis), resulting in the tissue turning black. Adjoining tissue forms a scab and ‘oozes’. When the infection is sufficiently established, the pig’s immune system becomes stimulated to react and fight the infection. Usually by the time the pig is mid-way through the finisher section the infection has been eliminated, however by that stage the damage is done.

A further problem can occur when the ‘scab’ is rubbed-off, either against other pigs or against pen walls that leads to some raw tissue becoming exposed. This attracts the attention of pen mates who may start to chew the ear / tail, which further exacerbates the problem

So how does the infection enter the pig’s body in the first place?

There is no definitive causation of the problem, however anecdotal evidence appears to suggest it may occur by two different pathways. The first is ‘leaky gut syndrome’ whereby the junctions in the small intestine wall remain open after the first 24- 48 hours of life, rather than closing as per normal. This ‘extended opening’ allows bacterial infection to cross the intestinal wall and circulate around the piglet’s body. The second suggested pathway is bacterial infection on the sow’s skin being transferred to the piglet’s skin during suckling. This bacteria then enters the piglet’s body after weaning, when piglets are fighting to establish the pen pecking order and therefore develop open cuts and scratches. The bacteria from either pathway then gets established and causes clinical infection a number of weeks later.

We have been weaning pigs like this for decades, why has ear necrosis only emerged in more recent times?

The ear necrosis emergence in the last 10 years may be due to the elimination of antibiotic usage in weaner feed. The Irish pig industry has virtually eliminated the use of zinc oxide and has made huge reductions in antibiotic usage, but a side- effect is that infections during the weaner phase can now get more established than in previous times. Another potential contributing factor is that sows traditionally used to be washed when entering the farrowing house, however this  practice diminished in more recent times due to lower staffing levels on farms.

So now that we ‘know our enemy’, what is the solution?

That is the ‘six-marker’ it really depends on which infection pathway is the causation! There is limited information on the causation of ‘leaky gut’ syndrome and this area is currently being extensively researched in pigs and humans. Hopefully we will know more about this syndrome in the coming years but in general the following practices may reduce the incidence/risk; reducing the disease load through vaccination, achieving high birth weights, stimulating high colostrum production & piglet intake.

The second suggested infection pathway arising from cuts being infected from skin bacteria (Straphylococcus Aureus?) is easier to treat. Eliminate/reduce the source of the bacteria by washing the sows with disinfectant either prior to or immediately on entry to the farrowing room. Then aim to minimise piglet aggression at mixing and when it occurs, disinfect the wounds/cuts. A number of pig producers I have worked with recently have found the regime below has significantly reduced the incidence of ear necrosis on their units.

Hopefully by knowing more about this enemy it may help to eliminate this problem on your unit!

Suggested ear necrosis battle plan!

  1. Wash the sows with disinfectant prior to entry into farrowing house
  2. Ideally a couple of days before weaning, lift sufficient dividing boards between farrowing pens to allow piglets to mix. Mix the required number of litters to match your weaner pen accommodation, for example if a weaner pens hold 35 pigs then mix 3 litters in the farrowing house and move this entire group into a single pen at weaning
  3. If mixing piglets in the farrowing house, spray them with disinfectant on the day the boards are lifted /mixed, to keep any cuts clean
  4. DO NOT grade pigs at weaning, it does not help performance and will increase the fighting intensity, producing more injuries
  5. Do not ‘sex’ your piglets at weaning
  6. Spray weaned pigs with disinfectant in the weaner house on the day of weaning & for the following 2 days (3 days in total) to ensure all cuts are kept clean
  7. Ensure pigs have the proper floor space allowance and optimum feeder access/space
  8. Ideally wean all damline piglets (males & females) together into pens on their own
  9. Consult your unit vet to fine-tune the recommendation for your unit

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