Table 1 Variables assessed for association with post-mortem presence of bTB visible lesions
Variable | Description |
|---|---|
Reason for removal | Categorical; 1. Negative in contact; 2. IFN-γ; 3. SICCT |
Bovine reaction size | Reaction to bovine tuberculin injection (in mm) during skin testing for bTB |
Avian reaction size | Reaction to avian tuberculin injection (in mm) during skin testing for bTB |
b-a reaction difference | Bovine reaction minus avian reaction to tuberculin injection during skin testing for bTB (in mm) |
BVD test result | Binary; RT-PCR test result for ear-tag samples |
Inconclusive BVDV result | Binary; inconclusive RT-PCR test result for ear-tag samples |
Indirect BVDV test result | Binary; if one animal in a herd tests + for BVDV then all animals from that herd gets assigned an indirect +; otherwise - |
Fascioliasis | Binary; Presence of active infection of F. hepatica = 1; absence of active infection = 0 |
Fluke damage | Binary; Presence of fluke damage = 1; absence of fluke damage = 0 |
Fluke general | Binary; Presence of either Fascioliasis or fluke damage = 1; absence of Fascioliasis and absence of fluke damage = 0 |
VL | Binary; presence of a bTB like visible lesion (VL) |
Age-quartiles | Animal age in years at death; categorised into quartiles. |
Breed | Breed of animal (breeds associated with dairy or non-dairy) |
Sex | Male or female |
Associated herds | Number of herds from birth to death |
Number of lifetime moves | Number of movements from birth to death, including market moves |
Time since last test | Time from penultimate to ultimate test |
bTB Herd history (4Â years) | Binary, whether the last herd the animal resided in had a history of bTB over the preceding 4Â years |
Penultimate SICCT reading | Whether the animal was a severe interpretation reaction at penultimate test (binary) |
Total reactors at disclosure | Total number of reactors disclosed during the breakdown where the animal was SICCT positive (Breakdown size). Note, that the breakdown was defined as the total period over which the herd was restricted, with the total number animals removed over that period. |
Herd size | Total animals within the herd at time of testing; categorised into quartiles |
Number of purchased animals | Number of bought-in animals during the last 3Â years; categorised into quartiles |
Region | Location based on three categories (North, South-west, South-east) |