Multi-pathogen epidemiological survey of subclinical mastitis, gastrointestinal parasitism, and zoonotic diseases in smallholder dairy cattle in South Sulawesi, Indonesia.

BACKGROUND AND AIM: Smallholder dairy cattle systems in Indonesia face persistent health challenges that compromise productivity, milk quality, and public health. This study aimed to investigate the prevalence of subclinical mastitis, gastrointestinal parasitism, and selected zoonotic diseases (Mycobacterium bovis and Brucella abortus) in smallholder dairy cattle in Enrekang Regency, South Sulawesi, a key dairy production center in eastern Indonesia.

MATERIALS AND

METHODS

A cross-sectional survey was conducted in July 2025 across 29 smallholder farms involving 94 dairy cattle. Serological screening (enzyme-linked immunosorbent assay for bovine tuberculosis (bTB) and Rose Bengal Test for brucellosis) was performed on 90 animals. Subclinical mastitis was assessed in 73 lactating cows (289 quarters) using the California Mastitis Test (CMT), with CMT-positive samples (score ≥2) subjected to bacteriological culture and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identification. Gastrointestinal parasites were examined in 94 fecal samples using direct smear, flotation, and sedimentation techniques. Descriptive statistics and 95% confidence intervals (CIs) were calculated.

RESULTS

All serum samples tested negative for bTB and brucellosis. Subclinical mastitis prevalence was high: 38.75% at quarter level (112/289; 95% CI: 33.2-44.6%), 75.34% at cow level (55/73; 95% CI: 64.2-84.1%), and 86.21% at herd level (25/29; 95% CI: 68.8-95.0%). Dominant bacterial isolates included Streptococcus uberis (16.7%), Streptococcus agalactiae (13.3%), and Staphylococcus aureus (13.3%). Gastrointestinal parasitism affected 75.53% of cattle, with strongyle-type eggs (39.36%), Strongyloides spp. (30.85%), Eimeria spp. (21.28%), and Fasciola spp. (14.89%) most prevalent. Co-infection of mastitis and parasitism occurred in 56.16% of lactating cows.

CONCLUSION

This first multi-pathogen survey in Enrekang Regency revealed the absence of major zoonotic bacterial diseases alongside a high burden of subclinical mastitis and gastrointestinal parasitism. These findings highlight the predominance of endemic, productivity-limiting conditions in smallholder dairy systems and underscore the need for integrated control programs focusing on milking hygiene, housing sanitation, and strategic parasite management.