Diphacinone and zinc phosphide toxicity in a flock of Peafowl

Abstract

Toxicity probably due to a combination of diphacinone and zinc phosphide was diagnosed in a flock of peafowl, in which 35 birds in a flock of 80 died over a span of 10 days without any apparent clinical signs. Chickens and guinea fowl, 30 each on the same premises, were not affected. Plastic tubes containing diphacinone and zinc phosphide were used on the premises to control ground squirrels. Most of the six dead peafowl, which ranged in age from 6 months to 4 years, had an accumulation of serosanguinous fluid in the abdominal cavity, semi-clotted blood over the liver lobes, increased pericardial fluid, and enlarged and pale kidneys. Pellets of diphacinone and zinc phosphide were found in the crop and gizzard contents from most of the birds. Microscopically, most of the birds had mild to moderate centrolobular degeneration of hepatocytes and multifocal degeneration of myofibres in the heart with infiltration by a few mononuclear cells. Acute nephrosis and mucosal oedema in the oesophagus and crop were also observed. Toxicological analysis of the crop and gizzard contents revealed the presence of diphacinone and phosphine gas, and analysis of the crop contents from two birds for heavy metals revealed zinc levels of up to 6600 parts/10 6 . It was suspected that only the peafowl and not the chickens and guinea fowl were affected because peafowl, with their longer necks, were able to reach into the plastic tubes and eat the pellets.