It arises from penetrating wounds, extension from adjacent tissues or by hematogenous spread, especially umbilical infection in the newborn. More common in farm animals than dogs and cats. Some specific causes are erysipelas in pigs and sheep, Streptococcus spp. in pigs, calves and lambs, coliforms in calves, Haemophilus spp. in pigs (Glasser's disease) and lambs, Arcanobacterium spp. in lambs, and Chlamydophila pecorum in calves and lambs.