Clinical progression of a case of toe-tip necrosis syndrome in a feedlot steer.

A fractious feedlot steer was diagnosed with hind-limb lameness at 19 d on-feed. Clinical examination (Week 0) revealed white line separation of both lateral digits of both hind feet. Debridement confirmed toe-tip necrosis syndrome and the steer was treated with oxytetracycline (20 mg/kg, SC) and meloxicam (0.10 mg/kg, SC). Radiographs revealed osteolysis of P3 bones of both lateral digits, and by Week 4 the medial claw of the right hind foot was similarly affected. Clinical and radiographic examinations were conducted over a 25-week period. Rectal temperature, body weight (BW), cortisol (salivary and hair), haptoglobin, and complete blood (cell) counts were obtained over a 22-week period. New horn growth covered the debrided sole defects by Week 7, and radiographs confirmed remodelling of the P3 bones. At slaughter (Week 25), both hind feet appeared normal except for the lateral digits being longer than the medial digits. Radiographs indicated permanent changes in the P3 bones. Although this animal had osteolysis in 3 of 4 hind-limb digits, it was successfully treated with antimicrobial therapy and debridement on Week 0 followed by a second debridement in Week 2. Early intervention and debriding are central to preventing other sequelae such as deep digital sepsis. Key clinical message: A feedlot steer diagnosed with toe-tip necrosis syndrome, including osteolysis of 3 of 4 hind-limb digits, was successfully treated with debridement and antimicrobial therapy. Radiographic examinations confirmed remodeling of the distal phalanges (P3) and absence of active infection 25 wk after treatment. This case underscores that feedlot animals with osteolysis of multiple P3 bones can be treated successfully using debridement and antimicrobials.