Effects of injectable famphur on young Brahman and Angus cattle.

Clinical responses were monitored in young Angus and Brahman bulls given IM injections of an experimental solution of 35% famphur in a dose 5 times greater than the recommended dose (83.2 mg/kg). Five of the 6 treated Brahman bulls had severe clinical signs of organophosphorous toxicosis, and 4 died within 48 hours after they were dosed. Only 1 of the 5 treated Angus bulls showed clinical signs of toxicosis and it recovered. In a subsequent trial, clinical and cholinesterase responses were monitored in young Brahman bulls, steers, and heifers given famphur at different dosages. Highly significant (P < 0.001) RBC cholinesterase inhibition over the 28-day trial was observed in animals given 16.6, 33.3, and 49.9 mga of the drug/kg. In comparison to Brahman heifers and steers, a lower treatment level of famphur (33.3 mg/kg) induced toxicosis in bulls. However, no significant differences in RBC or plasma cholinesterase inhibition were found to be due to treatment-sex interactions.