Prevalence, Bacterial Etiology, and Risk Factors of Clinical and Subclinical Mastitis in Dromedary Camels (Camelus dromedarius) Across Pastoral and Peri-Urban Production Systems in Somalia

Mastitis is a major constraint to camel milk productivity, udder health, and milk safety in Somali pastoral and emerging peri-urban dairy systems, yet comparative epidemiological data across these systems remain scarce. This cross-sectional study investigated the prevalence, bacterial etiology, and risk factors of mastitis in lactating dromedary camels in Somalia, and examined the relationship between California Mastitis Test (CMT) score and somatic cell count (SCC), together with antibiotic residues in a subset of milk samples. Between August 2024 and January 2026, 384 lactating camels from pastoral and peri-urban production systems were enrolled, yielding 1,536 quarter milk samples. Clinical mastitis was assessed by udder examination, subclinical mastitis by CMT, SCC was measured in 1,419 quarter samples, and bacteriological culture was performed on quarter milk samples. At camel level, 48.4% had clinical mastitis, 91.7% had at least one CMT-positive quarter, and 68.2% had at least one culture-positive quarter. At quarter level, the prevalence of clinical mastitis, CMT positivity, and culture positivity was 16.5%, 47.8%, and 24.6%, respectively. Coagulase-negative staphylococci were the most frequent isolates (28.0%), followed by Staphylococcus aureus (21.7%), Escherichia coli (13.0%), Streptococcus agalactiae (10.8%), and Streptococcus uberis (9.8%). Median SCC increased progressively from 99,548 cells/mL in CMT score 0 quarters to 2,542,414 cells/mL in CMT score 3 quarters (p < 0.001). In multivariable generalized estimating equation analysis, peri-urban production system (AOR 1.54, 95% CI 1.23–1.93), mild teat lesions (AOR 1.61, 95% CI 1.18–2.19), and severe teat lesions (AOR 2.04, 95% CI 1.29–3.24) were significantly associated with quarter-level CMT positivity. Antibiotic residue screening identified confirmed positives in a subset of milk samples, with beta-lactams predominating. These findings show that mastitis is widespread in Somali camel dairying and is shaped by both bacterial infection and modifiable management-related factors, particularly under peri-urban conditions. Improved udder-health surveillance, teat-health management, and prudent antimicrobial-use practices are needed to reduce disease burden and improve camel milk safety.