Assessment of gastrointestinal nematode infections in dairy cattle and the associated risk factors in Northern China.

Importance: Gastrointestinal nematodiasis poses significant economic losses in the livestock industry due to mortality, morbidity, and decreased production.

Objective: This study examined the prevalence of gastrointestinal nematodiasis in dairy cattle in Central Inner Mongolia, Northern China, the associated risk factors, and the effects on the pepsinogen and gastrin levels.

Methods: Fecal samples (n = 590) were collected from four regions and analyzed using the standard floatation and sedimentation techniques. The serum gastrin and pepsinogen levels were also assessed as potential biomarkers for gastrointestinal nematodiasis.

Results: Among 590 animals, 259 (43.9%; 95% confidence interval, 36.7-49.8) tested positive for at least one type of gastrointestinal nematode parasite. Among the positive animals, 38.6% were poly-parasitic, while 61.4% were mono-parasitic (p < 0.05). Cooperia was the predominant nematode among mono-infections, accounting for 10.8%, followed in order by Oesophagostomum (10.0%), Trichuris (9.6%), Trichostrongylus (8.5%), Dictyocaulus (6.9%), Ascarid (6.9%), Haemonchus (4.6%), and Strongyloides (3.9%). Among the poly-parasitic infected cattle, 22.7%, 9.3%, 4.2%, and 2.3% had two, three, four, and five parasite combinations, respectively. The risk factors, such as age, breed, area, physical condition, and presence of diarrhea, were significantly (p < 0.05) associated with the prevalence of gastrointestinal nematodiasis. Poly-parasitic infected cattle showed 49.1% higher (p = 0.013) serum pepsinogen levels than the control group, while the mono-parasitic ones exhibited a 28.33% increase (p = 0.030). Similarly, the serum gastrin levels increased by 99.2% (p = 0.004) and 71.3% (p = 0.015) in the poly-parasitic and mono-parasitic animals, respectively.

Conclusions and relevance: These findings demonstrate the high prevalence of gastrointestinal nematodiasis in Northern China, with an alarming rate of poly-parasitic infections. In addition, polyparasitic infections affect the enzymes pepsinogen and gastrin levels.