Abstract:

To investigate dairy cow coccidiosis infection status and epidemic characteristics in Ningxia, the fecal samples of calves with diarrhea collected from five large scale dairy farm in Wuzhong, Shizuishan and Helan of Ningxia were collected. The morphology, species and infection status of pathogeny were counted by saturated NaCl floating method and McMaster Egg Slide Counting method. Genomic DNA of coccidial oocyst was extracted for amplification and sequencing of 18S rRNA. DNAstar was used for sequence analysis with the published 18S rRNA gene of coccidia of dairy cattle, and a phylogenetic tree was constructed. Results showed that in the random of 179 samples, the average cow coccidiosis infection rate was 56.98%, the range of infection rate was 40.00%-80.84%, and average number of oocysts per gram feces (OPG) value was 1 358. Morphological observation showed that sporogenous oocysts were round or elliptic, and preliminarily demonstrated the dominant species in this area were Eimeria zuerni and Eimeria bovis, whose size were (25.7-36.0)μm×(21.4-27.1)μm. Sequence analysis showed that strains isolated from Ningxia had a distant relationship with other strains, but there was a close relationship between the local strains. This study not only enriched the epidemiological materials of dairy cow coccidiosis, but also laid a foundation for the prevention and treatment of the disease.

Key words: Ningxia, cow, coccidia, genetic evolution