Epidemiology and Economic Impact of Mastitis in Smallholder and Commercial Dairy Herds in Oyo State

This study investigates the epidemiology of mastitis in smallholder and commercial dairy herds in Oyo State, South West Nigeria, quantifying prevalence, characterising causative organisms, identifying risk factors, and estimating the economic cost of the disease. Mastitis is universally recognised as the most economically significant disease of dairy cattle, causing losses through reduced milk production, treatment costs, premature culling, and milk quality failures. Despite this importance, rigorous epidemiological data on mastitis in Nigerian dairy herds are limited, constraining the design of cost-effective control programmes. This study surveys 45 dairy operations (20 commercial and 25 smallholder) in Ibadan, Ogbomoso, and Oyo local government areas, conducting California mastitis tests on 680 individual cows and collecting aseptically obtained quarter milk samples from CMT-positive quarters for bacteriological culture and antibiotic sensitivity testing. Logistic regression identifies risk factors associated with subclinical and clinical mastitis at cow and herd levels. An economic model estimates total annual mastitis cost per cow and per farm. Findings reveal overall quarter prevalence of 34 percent for subclinical mastitis and 8 percent for clinical mastitis across all sampled herds. Staphylococcus aureus is the most prevalent pathogen (42 percent of isolates), followed by coagulase-negative staphylococci and Streptococcus species. Risk factors for high mastitis prevalence include inadequate teat dipping, poor hygiene at milking, and absence of dry-cow therapy. Annual economic losses average 126,000 naira per cow from mastitis across all farms. The study recommends a structured mastitis control programme as the highest-return animal health investment for Oyo State dairy operations.

Keywords: mastitis epidemiology, dairy cattle, Oyo State, Staphylococcus aureus, economic loss.