Veterinary Services

Three layer pullets aged 14 weeks were submitted from a flock with a history of increasing numbers of birds being found dead.

All three birds were in good body condition and had food in the crop and gizzard. The trachea of one bird contained excess mucus and had pinpoint haemorrhagic foci, and the tracheas of the other birds contained large blood clots. Infectious laryngotracheitis was suspected and was subsequently confirmed by histopathology and virus isolation. The flock had received a live vaccine against infectious laryngotracheitis by spray 10 days before the onset of mortality. SAC VS says that a combination of inadequate exposureto the vaccine by some birds, followed by recirculation of the vaccine virus, probably precipitated the deaths;  approximately 1 per cent of the flock died.

Egg yolk peritonitis and impaction of the oviduct was found in two layers. One of the birds had been dull for four days and appeared bloated, and the second bird had diarrhoea and weight loss over a seven-week period.

Marek’s disease was diagnosed in a two-year-old male Pekin bantam and in a two-year-old layer that had become thin and stopped laying.

Early involvement of Marek’s disease was also suspected in two free-range hens aged six months that lost condition and became listless.Crop impaction was found at postmortem examination, but histopathological lesions in the spleen of one bird were suspicious of early neoplasia.

Lesions typical of histomonosis (blackhead) were found in the liver and caeca of turkeys aged 13 and 14 weeks from two small flocks of Christmas turkeys. 

Spontaneous turkey cardiomyopathy (round heart disease of turkeys) was a cause of sporadic mortality in turkeys from three weeks of age, and aortic rupture (dissecting aneurysm) caused the death of a large male turkey after fighting had been observed in the group.