06/06/2026
🐄 Gangrenous Mastitis in Cows ("Blue Bag")
What it is: A peracute, life-threatening veterinary emergency in dairy cattle caused by Staphylococcus aureus or E. coli. The bacteria release necrotizing toxins that cause severe blood clots, cutting off the blood supply and causing rapid tissue death (gangrene).
⚠️ Key Signs
Systemic Shock: High fever (dropping to subnormal), severe depression, dehydration, and hind-leg lameness due to extreme pain.
Udder Changes: The affected quarter goes from hot and swollen to cold, numb, and blue-black/purple with a clear line separating dead tissue from healthy skin. It may crackle under the skin (gas production).
Secretion: Milk is replaced by a foul-smelling, watery, bloody fluid with dark clots.
💉 Treatment Strategy (Goal: Save the Cow)
Aggressive Medicine: Immediate systemic broad-spectrum antibiotics, heavy IV fluids for endotoxic shock, and NSAIDs (like flunixin meglumine) for pain and inflammation.
Surgical Drainage: Teat amputation of the affected quarter to allow constant drainage of toxic fluid, or a complete mastectomy once the cow is stable.
Sloughing: If the cow survives without radical surgery, the dead quarter will naturally dry up and slough off over several weeks, requiring strict wound hygiene and fly prevention.
