Challenges and insights in morphological identification of Eimeria species in cattle: a comprehensive study and identification key

This study aimed to enhance morphological identification of Eimeria species in cattle of Kashmir through comprehensive analysis of oocyst morphology, body shape index, micropyle presence, dimensions, and sporulation time and prepare a taxonomic key for the identification of Eimeria in cattle. A total of 1198 faecal samples were collected by per rectal method with 589 (49.2%) testing positive for Eimeria species. Subsequently, 845 Eimeria oocysts from various samples were analyzed for shape assessment and measurement of dimensions using micrometry. Nine Eimeria species were identified based on morphological characteristics, including E. zuernii, E. bovis, E. alabamensis, E. auburnensis, E. canadensis, E. subspherica, E. ellipsoidalis, E. cylindrica, and E. brasiliensis. Additionally, an unidentified Eimeria species exhibiting morphological similarities to E. alabamensis and E. bovis was discovered, distinguished by a distinct and conspicuous micropyle absent in either species. Emphasis was placed on identifying recurring characteristics within certain oocysts, and a key was formulated to enhance oocyst identification. Our findings contribute to the understanding of Eimeria species diversity in cattle populations, underscoring the importance of comprehensive morphometric analysis for accurate species identification and epidemiological surveillance. Further research is warranted to elucidate the genetic diversity and pathogenicity of identified species, as well as to refine identification methods and develop effective disease management strategies.