Background: Coccidiosis, caused by protozoan parasites of the genus Eimeria, is a common intestinal disease in cattle and calves that leads to digestive problems, reduced growth, and economic losses in livestock production. Despite its importance, little information exists on the prevalence of Eimeria infection among free-grazing cattle in eastern Golestan Province, Iran. This study aimed to estimate the prevalence of Eimeria infection in this region. Methods: A cross-sectional study was carried out during spring and summer on 348 free- grazing cattle from rural areas around Kalaleh, Maraveh Tappeh, Galikesh, Gonbad Kavus, and Minoodasht counties. Fresh fecal samples were collected immediately after defecation, including 289 adults and 59 calves. Detection of Eimeria oocysts was done using the Clayton- Lane flotation technique. Results: Overall, Eimeria oocysts were found in 68 samples (19.5%). Among adults, 60 of 289 (20.8%) were infected, while 8 of 59 (13.6%) calves tested positive. These results show a moderate prevalence of infection, with a higher rate in adults than calves. The prevalence rates in the study areas were as follows: Galikash (44.11%), Minoodasht (20.58%), Gonbad Kavus (14.73%), Kalaleh (10.29%), and Maraveh Tappeh (10.29%). The intensity of contamination was “1+” , and the OPG count under a 10x lens ranged from 1 to 10 oocysts. Conclusion: This study indicates that Eimeria infection in free-grazing cattle and calves in eastern Golestan Province is notable. It highlights the need for improved hygiene and parasite control in traditional farming. Regular monitoring, farmer education, and improved husbandry are essential to reduce infection, enhance animal welfare and productivity, and support sustainable livestock production.

Keywords