Veterinary Services

Poultry

Ten ducks died suddenly within 20 minutes of being let outdoors on a free-range unit. Within eight hours there were about 20 deaths in total from the batch of 500 ducks. There was concern that the birds may have consumed an anticoagulant rodenticide but there was no evidence of haemorrhage at post mortem examination. There were mild aspergillosis lesions. The initial toxicology report noted low levels of the anticoagulant rodenticide bromadiolone in the livers of the two birds sampled. Further toxicological analysis of gizzard contents revealed that the birds were also exposed to bendiocarb, which is an acutely toxic carbamate pesticide. Bendiocarb poisoning was considered to be the cause of the rapid deaths, and the Scottish Agricultural Science Agency is conducting an investigation to determine the source of the poison.

Game birds

The gamebird "season" continued with submissions from released birds. Spironucleosis (hexamitosis) was confirmed in pheasants aged 16 weeks following their exit from release pens. The same condition was diagnosed in red-legged partridges around 10 days after their arrival on an estate. Approximately 900 birds had died from the consignment of 14,000 birds. Significant numbers of coccidial oocysts were also detected in these birds. Two 12-week-old pheasants were received from an estate that had experienced 50 deaths in a group of 250 birds. Affected birds were described as thin and scouring. At necropsy both birds were thin with varying amounts of food in the gizzards. No motile protozoa or coccidial oocysts were seen, but large and small tapeworms were demonstrated in the intestinal contents.

Three live nine-week-old pheasant poults were submitted from a pheasant rearer. The birds had recently had their beaks trimmed and new bits fitted. On clinical examination the birds were alert but unwilling to walk, and two had swollen hocks. The only abnormality noted on examination of the carcases was an increased volume of synovial fluid within the tibiotarsal joints of the two birds with swollen hocks. Staphylococcus aureus was isolated from the tibiotarsal joints of all three birds, and staphylococcal arthritis/synovitis was diagnosed. This is a relatively common condition in pheasant poults, with wounds being the portal of entry for the bacteria. Wounds can be accidental or, as seems likely in this case, due to procedures such as beak trimming.

Four young red-legged partridges were submitted from a holding where there had been several deaths after a short period of malaise. One bird had an enlarged liver and spleen with widespread pale mottling. Two birds had severe pericarditis with white deposits within the pericardial sacs. The fourth bird had early pericarditis and pulmonary oedema. Yersinia pseudotuberculosis was isolated in systemic distribution from three of the birds. Yersiniosis was also initially suspected in red-legged partridges aged 16 weeks, in which multiple necrotic areas were noted in the liver and spleen. Ziehl-Neelsen smears for mycobacteria were negative, and no significant bacteria were isolated. Histopathology subsequently demonstrated lesions consistent with histomoniasis.

Lead poisoning was believed to be the cause of wasting and death of a pet guineafowl. Necropsy revealed that the proventriculus and gizzard were greatly impacted with vegetation, and the kidney lead value was 161 parts per million dry matter. The source was traced to lead solder on an old pipe that had been unearthed.

Pigeons

Pigeon paramyxovirus 1 (PPMV-1) was isolated from young racing pigeons from two lofts. Mortality, diarrhoea and a small number of birds showing neurological lesions were reported in both lofts. The birds had not been vaccinated against PPMV-1. The Divisional Veterinary Managers of the local Animal Health Offices were informed of the suspicion of disease because PPMV-1 is a notifiable disease.

Wild birds

Necrotic oesophagitis, presumed to be the result of infection with Trichomonas species, was diagnosed in 10 greenfinches (Carduelis chloris), four chaffinches (Fringilla coelebs), a goldfinch (Carduelis carduelis) and a woodpigeon (Columba palumbus) from 14 sites. Trichomoniasis was also considered to be the cause of death of a sparrowhawk (Accipiter nisus). It had a severe necrotic oesophagitis and was from a site on which trichomoniasis had been confirmed in finches.