Table 1.
Histopathological features found in the tail tips of tail docked piglets
| Pathological feature | Time after tail docking |
Significance1 |
Significance2 |
|||
|---|---|---|---|---|---|---|
| 1 Week | 4 Weeks | 8 Weeks | 16 Weeks | P-value | P-value | |
| Surface crust/debris | 4/4+++ | 3/4+ | 2/4+ | 3/4+ | ||
| Surface bacteria | 4/4+++ | 3/4+ | 3/4+ | 4/4+ | ||
| Hyperkeratosis (orthokeratotic) | 1/4+ | 4/4+++ | 4/4+ | 4/4+++ | ||
| Parakeratosis | 2/4+ | 3/4+ | 4/4+ | 2/4+ | ||
| Epidermal hyperplasia | 4/4+++ | 4/4++ | 4/4++ | 4/4++ | ||
| Spongiosis | 3/4++ | 0 | 0 | 2/4+ | ||
| Anastomosing rete pegs | 3/4+++ | 4/4++ | 4/4++ | 4/4++ | ||
| Subcorneal pustules∗ | 1/4+++ | 0 | 1/4+ | 0 | ||
| Intra-epidermal pustules∗ | 1/4+ | 1/4+ | 1/4+ | 0 | ||
| Full re-epithelialization | 1/4 | 4/4 | 4/4 | 4/4 | ||
| Epidermal erosion∗ | 2/4+ | 0 | 0 | 0 | ||
| Ulceration∗ | 2/4+++a | 0b | 0b | 0b | 0.046 | <0.05 |
| Superficial perivascular inflammation | 2/4++ | 1/4+ | 2/4+ | 2/4+ | ||
| Deep perivascular inflammation | 1/4++ | 0 | 1/4+ | 0 | ||
| Dermal oedema∗ | 4/4+a | 0b | 0b | 0b | 0.013 | <0.05 |
| Fibroplasia | 3/4+++ | 4/4+++ | 4/4+++ | 4/4+++ | ||
| Dermal angiogenesis | 4/4+++ | 4/4++ | 4/4++ | 2/4++ | ||
| Granulation tissue | 4/4+++ | 4/4+++ | 4/4+++ | 4/4+++ | ||
| Thrombosis | 1/4+ | 0 | 0 | 0 | ||
| Dermal neutrophilic inflammation∗ | 4/4+++ | 2/4++ | 2/4+ | 2/4+ | ||
| Cellulitis∗ | 1/4+ | 0 | 0 | 0 | ||
| Osteomyelitis∗ (where bone was present) | 0 | 0 | 0 | 0 | ||
| Bone remodelling (where bone was present) | 2/4+ | 0 | 1/4+ | 0 | ||
| Myofibre atrophy | 4/4++ | 1/4+ | 0 | 0 | ||
| Myofibre regeneration | 3/4+ | 1/4+ | 0 | 1/4+ | ||
| Nerve/axonal proliferation† | 3/4++ | 4/4++ | 4/4++ | 4/4++ | ||
| Neuroma/neuromatous tissue† | 0a | 2/4++a | 4/4++b | 4/4++b | 0.011 | <0.05 |
| Axonal infiltration of superficial dermis† | 4/4+ | 4/4++ | 4/4++ | 3/4+ | ||
Data values represent the number of pigs at each time point after tail docking exhibiting that feature. + symbols represent the maximum observed abundance score (+, low; ++, medium; +++, high) of four pigs at that time point after docking. Significance1 shows comparison of prevalence of that feature for tail docking (TD) + 1 week against all later time points (Fisher's Exact test: same superscripts do not differ significantly). Significance2 shows comparison of the maximum abundance scores for TD + 1 week against all later time points (Mann–Whitney U test).
∗
Features deemed likely to induce or maintain pain.
†
Identified by S100 IHC.