Comparison of the macroscopic and microscopic lesions in the rabbits from groups ST96 (left) and ST121 (right). ST96: lesion classified as mild, characterised by small and scarcely extensive abscesses, some of which were only histologically visible. ST121: lesion classified as moderate, characterised by great mammary gland tissue thickening and induration, produced by several coalescing abscesses. Haematoxylin and Eosin. Bar = 0.2 cm.