Effect on time in quarantine of the choice of program for eradication of footrot from 196 sheep flocks in southern New South Wales

Abstract

To identify and compare programs for eradicating virulent footrot (VFR) chosen by owners of quarantined sheep flocks in southern New South Wales. Data from 196 sheep flocks in the Wagga Wagga and Young Rural Lands Protection Boards were used to determine the program chosen, the influence of flock size on the program chosen and the effects of the program chosen and the use of contractors on the time in quarantine. The most popular programs in flocks using a single program were: total destocking (61/173; 35.3%) and inspection and culling of affected animals (71/173; 41.0%). Treatment of known infected animals was chosen in 41 flocks and of those, 10 (5.8%) used antibiotics for treatment and 31 (17.9%) used foot-bathing. Combined programs were used in 23 flocks and in 10 flocks a change of program occurred before eradication was achieved. The choice of program was, to some extent, affected by flock size, with owners of small flocks (<500 sheep) more likely to destock. The chosen program strongly influenced the time in quarantine, the shortest time being for destocking (mean 284 days), followed by culling of infected sheep (395 days), treatment with antibiotics (433 days) and finally foot-bathing (502 days). Time in quarantine was significantly shorter when contractors were used. All the options chosen led to the eradication of VFR. However, in this sample both the choice of program and the use of contractors influenced the time taken to achieve eradication and therefore the time in quarantine. Based on time in quarantine, foot-bathing was the least desirable option for the eradication of VFR because of the significantly greater time involved, perpetuation of risk to neighbours and increased cost of inspections. These findings were derived from flocks that were quarantined, but they are relevant to all flock owners considering eradication of VFR.