Veterinary Services

Mortality in a small flock of caged layers approached 3% over a four week period in January.  Deaths commenced when birds were 39 weeks old, and consistent post mortem features were varying combinations of fibrinous pericarditis, fibrinous perihepatitis, egg yolk peritonitis and congested oedematous lungs.  Heavy and pure growths of Escherichia coli were recovered from the viscera.  A small number of birds also had a unilateral caseous cellulitis affecting the tissues of the face below the eye, sometimes extending into the wattle (Figure 3 - click on PDF link in right hand column).

Heavy growths of E coli were isolated from the affected tissues. Extensive investigations have not detected any underlying respiratory pathogens to date, but investigations are continuing. There have been reports of a substantial increase in the incidence of colisepticaemia in layer flocks in many European countries from the mid-1990s, with no evidence of predisposing respiratory infections (Vandekerchove D, De Herdt P D, Lavens H, Butaye P, Meulemans G and Pasmans F [2004] Avian Pathology 33, 298-302).

Low-grade mortality in broiler chicks in the first week of life was the result of yolk sac infections and non-starters. Higher mortality was seen in another broiler flock due to losses from baby chick nephropathy in the first week of life. A problem with the nipple drinker lines may have predisposed to baby chick nephropathy on this site.

Marek’s disease was diagnosed in a seven-month-old bantam from a small flock. Several of the brood of bantams had developed a high stepping gait, droopy wings, paralysis and finally death.