Klebsiella-associated mastitis and elevated SCC in a small dairy herd

Mastitis remains one of the most economically important diseases in dairy cattle and often represents a complex herd-level challenge. This case series describes an investigation conducted on a small family dairy farm with 12 lactating cows, characterized by recurrent mastitis and persistently elevated somatic cell count (SCC). Initial microbiological examination identified Klebsiella oxytoca in one cow and Klebsiella pneumoniae in another, whereas other cultures were negative. Targeted antimicrobial therapy was administered according to antibiogram results. Although subsequent cultures were negative, SCC values remained markedly elevated but demonstrated a gradual decline over three consecutive sampling rounds. Two Klebsiella-positive cows were also diagnosed with reticular foreign bodies, and herd-level interventions included rumen magnet administration in all cows and reinforcement of hygienic measures. No new clinical mastitis cases were recorded during the follow-up period. These findings suggest that Klebsiella mastitis in small dairy herds may reflect substantial environmental bacterial pressure, while persistent SCC elevation indicates ongoing inflammatory and structural alterations of the mammary gland. Integrated management strategies are essential for long-term stabilization.