Clinical and pathological observations on field and experimental zoalene poisoning in broiler chicks and the effect of the drug on laying hens.
Depression and ataxia was seen in 24-day-old chicks accidentally fed excess zoalene from 14 days of age. The presence of a small amount of furazolidone in the ration probably exacerbated the effect. There were no deaths. No other causes could be found for the condition and replacing the rations with food containing less than the recommended level of zoalene and no furazolidone resulted in recovery within 4 to 5 days. In an experimental study the syndrome was reproduced in baby chicks with as little as 2(1/2) times the recommended level of zoalene in the food. Increasing the amount of zoalene hastened the onset and increased the severity of symptoms and markedly depressed weight gains; the addition of a small amount of furazolidone had a synergistic effect. Inappetance may be largely responsible for the depression in weight gain, and damage to Purkinje cells seems to account for the ataxia and nervous signs. In laying birds 10 times the recommended level of zoalene in the food over 30 days caused inappetance, cessation of egg production, and progressive weakness, but no nervous signs.
Jordan
F T
FT
University of Liverpool, Sub-Department of Avian Medicine, 'Leahurst', Neston, Wirral, Merseyside, U.K.
Howell
J M
JM
Howorth
J
J
Rayton
J K
JK