K.H. Webster1; K.E. Harr2, DVM, MS, DACVP; C.A. Albert3; T.D. Williams1, PhD; J.E. Elliott3, PhD
Brodifacoum is an effective tool for controlling rodent populations. Rodent-consuming birds, such as owls and raptors, in which rodenticide may bioaccumulate have a significant mortality risk. As a second-generation, long-acting anticoagulant, brodifacoum disrupts hepatic production of vitamin K-dependent clotting factors, necessary for a functional extrinsic coagulation pathway. The extrinsic or amplification pathway is critical for avian hemostasis and is most commonly measured by the prothrombin time (PT) assay. This study measured PT, activated clotting time (ACT), hemoglobin levels, and PCV in Japanese quail (Coturnix coturnix japonica) exposed to 0, 0.8, 1.6, 2.5, and 3.4 mg brodifacoum per kg body weight at 1, 3, 5 and 7 days post-exposure. ACT and PT in normal and corn oil control quail ranged from 48–170 and 11–15 seconds respectively. ACT and PT were prolonged in samples from quail gavaged at any dosage on day one with generally increased prolongation over time at days 3 and 5. Fifty fold prolongation was documented at the higher brodifacoum dosages and correlated to petechial hemorrhages found at necropsy. Prothrombin time and activated clotting time have proven to be reliable methods of assessment of brodifacoum exposure in quail and will therefore likely be useful in the assessment of rodenticide intoxication in owls, seabirds, and other impacted populations similarly to domestic species. Hepatic values of brodifacoum and metabolites have been measured in the quail and will be correlated with findings.