By Stuart Young BSc (Hons) BVetMed MRCVS
Director Mount Vets LTD.
The weather has been horrendous and we have seen problems associated with birds trudging through the soaked ranges. It is inevitable that the birds that go out onto the range will drink from the muddy puddles and ingest a host of bugs that can affect bird health.
Probably the biggest cause of death in laying birds is egg peritonitis or E.coli peritonitis and the drinking of that dirty, infected water certainly doesn’t help! The term egg peritonitis actually covers disorders of the egg-laying tract including impaction of the oviduct, peritonitis and infection of the oviduct. E.coli, however, tends to be the bug that kills the bird. The picture below shows a typical post-mortem of a bird with egg peritonitis and many of you will have seen this if you open birds yourself.
It often smells terrible with the thick yellow pus throughout the cavity and in summer the carcass often goes green quite quickly because of the bacteria.
How do the bacteria get into the bird?
Stress in the flock can lower the immune system to the extent that the E.coli can enter the bird from the gut, from the airways and breathe it in, from wounds such as pecking or as an ascending infection from the vent.
What are the common contributing influencing factors?
- Parasites such as worms or red mite
- Viral challenges such as IB
- Bacterial challenges such as Mycoplasma or Pasteurella. Incidentally IB, Mycoplasma and E.coli are a very potent mix and make mortality rates much higher than if these pathogens were present on their own.
- Stresses such as injurious feather pecking, cannibalism, predators, any management changes such as nest boxes, not opening, water supply issues or food running out, etc, heat stress.
How do we diagnose it?
We take samples from the heart, liver, oviduct and bone marrow to grow the E.coli but the post-mortem picture gives us a big clue. However, other infections are similar so it is important to do the bacteriology. It is also essential to do sensitivity tests to find out what is the best treatment to use when mortality is high.
How do we control egg peritonitis?
Antibiotics are limited in number with nil egg withhold and we can have poor response if we do not control the trigger factors so we are far better placed at preventing it
- Good biosecurity including effective rodent control and effective turnaround
- Clean water (regular water sanitation), clean food, clean air (good draught free ventilation essential)
- Well-drained ranges with fresh stone each crop outside the pop holes
- Paddock grazing to try to preserve pastures (difficult if not impossible this weather!)
- Avoid pecking by enrichment in the house, having access to the range early, good light control, control of egg size etc. (This is a huge topic in itself!)
- Control all parasites, internal (worms) and external (red mite)
- Control viral challenges by good vaccination programmes including vaccinating through lay for IB.
- Control predators
- Infeed prebiotics/probiotics etc such as Biomos, actigen, bactocell.
- A good in rear vaccination policy and healthy pullet delivered
- Vaccination for E.coli.
The vaccination for E.coli has been brought right up-to-date with the availability of Poulvac E.coli vaccine that is licensed in rear but has been used under veterinary supervision throughout lay. It has also been used in the face of an outbreak with good success but that has to be managed by your veterinary surgeon. If there are underlying issues such as aggression then again as with antibiotic success, we may not have the desired effects with vaccination.
We can also vaccinate with a bespoke vaccine, whereby we collect the E.coli from your post-mortems and make a vaccine specifically for your site, called autogenous vaccination. This can be very expensive and involve two injections in rear. These vaccines also have to be constantly updated in case new strains come onto your unit.
We are sure the weather will improve soon and then the birds will have a better chance on the range of avoiding the high bacterial loads.