Veterinary Services

Domestic poultry

A range of conditions was diagnosed in young chickens and turkeys from different sites, including infected yolk sacs, non-starters and colisepticaemia. Caseous caecal cores were found in turkey poults aged four to ten days, prompting fears of coccidiosis or salmonellosis. However smears for coccidial stages were negative, as were cultures for Salmonella, and the origin of the caecal cores was not determined. Further investigations are underway.

Thirteen six-day-old layer chicks were submitted with the history of increased mortality and nervous signs such as torticollis. Postmortem examination revealed splenomegaly and hepatomegaly, with pale pinpoint necrotic foci in the liver of some birds. Enterococcus hirae was isolated from several tissues including brain, and histopathology of brain demonstrated multifocal areas of acute necrosis in the cerebrum, brainstem and optic lobe. The necrotic foci were surrounded by hyaline capillary thrombi. The findings were consistent with encephalomalacia secondary to E. hirae infection.

Large quantities of clotted blood were found in the body cavity of an 18-week-old, hybrid layer replacement. The blood originated from an enlarged friable ovary containing multiple fawn nodules up to four centimetres wide (Figure 4 see top right-hand side). An ovarian adenocarcinoma was confirmed on histopathology. More commonly this is seen in birds over twelve months of age. Marek’s disease was confirmed on histopathology in a one-year-old layer that developed diarrhoea and lost weight. Small white nodules were found in the liver, kidney and intestinal wall, and the bursa of Fabricius was enlarged and firm.

Waterfowl

A three-year-old Muscovy drake was presented from a flock in which nine out of 20 birds died over several months. Postmortem examination revealed an enlarged liver with multiple pale necrotic foci (Figure 5 see top right-hand side). The spleen contained foci of necrosis, the epicardium was petechiated and the intestinal contents were mucoid. Pasteurella multocida was isolated from the viscera. These findings were consistent with a diagnosis of avian pasteurellosis (fowl cholera).

Mycotic airsacculitis caused by infection with Aspergillus fumigatus was confirmed in a nine-month-old emperor goose that was found dead. The bird was from a mixed group of geese, ducks and chickens, but no other birds were affected.

Wild birds

Further deaths from trichomonosis were seen in garden birds. Most of the affected birds were chaffinches (Fringilla coelebs). Salmonellosis also made its seasonal appearance in garden birds, with Salmonella Typhimurium DT 40 causing deaths in greenfinches (Carduelis chloris), a chaffinch and a siskin (Carduelis spinus) from three locations.

Foul play was initially suspected when a dead buzzard (Buteo buteo) was found near a game bird shoot. However no evidence of trauma or poisoning was found at necropsy and the bird was in poor body condition. Large numbers of small coccidial oocysts, which may have contributed to the poor body condition, were demonstrated in the intestinal contents. A buzzard from a different location died from a fracture of the atlanto-occipital joint. Traumatic damage following collision with overhead power lines was suspected in an adult whooper swan (Cygnus cygnus). Although there was no external evidence of trauma, the body cavities contained a large volume of clotted and unclotted blood.