VLA Report Highlights Diseases in Free-Range Flocks

UK - Among the cases in the VLA Monthly Scanning Surveillance Report for February 2010 were an outbreak of severe vent pecking in free-range layers, and 10 per cent mortality in another flock from Erysipelas.

7 April 2010

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Europe

Commercial Layers and Layer Breeders

Intestinal volvulus

Intestinal volvulus involving the mid small intestine and chronic salpingitis were seen in a submission of 58-week-old free-range layers with a history of sudden increase in mortality. No likely cause for the rotation of the intestine around the mesentery was discovered at post mortem examination. No worms were detected in the intestinal tracts and the digestive contents were unremarkable with no excessively fibrous-stringy contents. This condition is seen sporadically affecting a few individuals of older free-range flocks.

Vent pecking

Vent pecking was the only lesion seen in a sample of 36-week-old free-range layers submitted to investigate a problem of low egg production and loss of body condition since point of lay. Post mortem examination confirmed most birds were in poor bodily condition and not in lay.

Erysipelas

Deaths had occurred in free-range adult layers in one shed of 16,000. Up to 1,500 birds had died. One other group of birds on the farm was unaffected. Erysipelothrix rhusiopathiae was isolated from five of six birds submitted for post-mortem examination. The birds were at the end of lay and vaccination was advised for the next batches.

Broilers and Broiler Breeders

Cholangiohepatitis

Chronic cholangiohepatitis was the only lesion seen in a sample of 33-day-old broiler pullets. which were submitted for investigation following a rise in factory rejects due to hepatitis. Post mortem examination revealed enlarged livers with multi-focal to diffuse necrotic foci. Microscopic examination confirmed lesions of chronic cholangiohepatitis indistinguishable from the type sometimes seen as a sequel to subclinical necrotic enteritis.

Spinal abscess

Chronic spondylitis ('spinal abscess') was seen in a flock of 50-day-old broilers submitted with a history of poor performance. Post mortem examination revealed a ventral swelling of the spine in the vicinity of the free thoracic vertebra T4. Bacterial cultures of material from within the lesion produced good growth of Enteroccoccus–like colonies with biochemical features consistent with Enterococcus cecorum.