Co-grazing of sheep and goats may not be an issue from a parasitological perspective.

Gastrointestinal nematode (GIN) infections have a significant impact on the health and productivity of small ruminants, while data on mixed-species grazing systems in Central Europe are scarce. This study aimed to compare GIN species richness and infection intensity in co-grazed dairy sheep and goats under a conventional grazing system in the Czech Republic. Over a 12-month period, 210 goat and 196 sheep faecal samples were analyzed using the McMaster method, followed by larval culture. Both hosts harboured Haemonchus contortus, Trichostrongylus/Teladorsagia spp., and Oesophagostomum columbianum. Goats exhibited consistently higher egg shedding, with a mean peak egg count of 1240 EPG in June, whereas sheep reached a markedly lower peak of 620 EPG in February. In goats, H. contortus predominated year-round, while in sheep, Trichostrongylus/Teladorsagia spp. showed pronounced seasonal fluctuations, comprising up to 60% of larvae in autumn. Differences in infection intensity between species were statistically significant (U = 24 697.5, p < 0.001). These results support the hypothesis that co-grazing does not homogenise parasite burdens between host species and demonstrate species-specific seasonal infection dynamics. Such insights directly address the study's aim of characterising species composition and infection intensity in co-grazed sheep and goats, providing an evidence-based basis for optimising sustainable parasite management in mixed grazing systems.