SOME PRELIMINARY-OBSERVATIONS ON THE POSSIBLE RELATIONSHIP BETWEEN AMMONIA PRODUCTION FROM SOILED BEDDING IN CALF REARING SHEDS AND CALF ILLNESS

A limited field study of covered facilities used for raising dairy cal ves suggested that respiratory disorders and death rates were highest when calves were continuously housed on bedding composed of wood shavi ngs, where ventilation was poor and where automatic feeders were insta lled. High concentrations of ammonia were found in the urine-soaked be dding following overnight incubation. A prolific growth of mixed micro -organisms isolated from the shavings rapidly colonised plates of sele ctive urea medium. Death rates of 10% and 13.5% were observed on two p roperties. Respiratory distress was common and lung disease was intrac table to treatment on these farms. A. histopathological diagnosis of s ubacute purulent pneumonia with distal necrotising bronchiolitis was m ade, similar to lung lesions produced experimentally in cats, guinea p igs and rabbits exposed to ammonia gas.