Prevalence of Blood Parasite Infections in Dairy Cattle in Phatthana Nikhom District, Lopburi

Abstract

This cross-sectional study aimed to determine the prevalence of blood parasite infections in dairy cattle and identify factors associated with infection in Phatthana Nikhom District, Lopburi Province, Thailand. A total of 398 blood samples were collected from dairy cattle on 18 farms in nine subdistricts between October and December 2025. Blood parasite infection was diagnosed using Wright-Giemsa stain thin blood smears and packed cell volume (PCV) measurement. Data were analyzed using descriptive statistics and univariate odds ratios (ORs) with 95% confidence intervals (CIs).Of the 398 cattle examined, 125 tested positive for blood parasites, yielding an overall prevalence of 31.41%. The detected parasites were Theileria spp., Babesia spp., and Anaplasma spp., with Theileria spp. being the most prevalent. Single-species infections accounted for 98 cases (78.40%), whereas co-infections were detected in 27 cases (21.60%). The most common co-infection was Theileria spp. with Anaplasma spp. (10.40%).Univariate analysis showed that cattle older than 5 years were significantly associated with blood parasite infection (OR = 2.14; 95% CI: 1.02–4.50; p < 0.05). Farms without an ectoparasite control program were also significantly associated with infection (OR = 4.47; 95% CI: 2.57–7.76; p < 0.001), whereas routine ectoparasite control every three months was associated with lower odds of infection (OR = 0.28; 95% CI: 0.14–0.57; p < 0.001). The presence of ticks on cattle, ticks in housing areas, and horse flies on cattle was also significantly associated with infection (p < 0.001).In conclusion, blood parasite infections were relatively common among dairy cattle in the study area, with Theileria spp. identified as the predominant parasite. Animal age, farm management practices, and vector-related factors were significantly associated with infection. These findings provide baseline epidemiological information to support surveillance, prevention, and control of blood parasite infections in dairy cattle.