Evaluation of Gastrointestinal Endoparasites in Cattle in Central Spain: Focus on Calicophoron daubneyi with Coprological, Epidemiological, and Anthelmintic Insights

<i>Calicophoron daubneyi</i>, a rumen fluke increasingly reported in European livestock, has emerged as a relevant parasitic threat in cattle. This study investigated the prevalence and seasonal dynamics of gastrointestinal endoparasites in 382 fecal samples from 40 beef cattle farms (26 extensive and 14 semi-extensive) in central Spain. Samples were analyzed using flotation, sedimentation, and modified McMaster techniques, complemented by PCR confirmation of trematodes and a 25-variable epidemiological survey. <i>C. daubneyi</i> was detected in 38.74% of samples and 77.5% of farms, surpassing <i>Fasciola hepatica</i> (13.09%), gastrointestinal nematodes (42.15%), and <i>Eimeria</i> spp. (16.75%). Mixed infections were frequent. Seasonal shedding patterns varied by parasite, with <i>C. daubneyi</i> peaking in spring and winter. Statistical analyses (Kruskal-Wallis, ANOVA, Mann-Whitney U) revealed significant seasonal differences and confirmed higher <i>F. hepatica</i> egg counts in extensive systems (<i>p</i> = 0.0012). Anthelmintic treatment was infrequent and mainly guided by coprological diagnosis; ivermectin, closantel, albendazole, and nitroxinil were the most used drugs, though none fully effective against <i>C. daubneyi</i>. Anthelmintic resistance was not evaluated in this study. These findings confirm the emergence of <i>C. daubneyi</i> in central Spain and highlight the need for targeted surveillance and seasonally adjusted control strategies.