Haematological Responses of West African Dwarf Sheep to Natural Gastrointestinal Helminth Infection in Ogun State, South West Nigeria

Gastrointestinal helminthiasis is a major cause of production losses in small ruminants across sub-Saharan Africa, operating primarily through its deleterious effects on haematopoiesis and nutritional biochemistry. This study evaluated haematological changes in West African Dwarf sheep naturally infected with gastrointestinal helminths in Abeokuta, Ogun State, South West Nigeria. Seventy sheep were categorised into groups based on faecal egg count: low burden (fewer than 500 eggs per gram), moderate burden (500 to 1500 eggs per gram), and high burden (greater than 1500 eggs per gram), with fifteen helminth-free animals serving as controls. Blood samples collected by jugular venipuncture were evaluated for packed cell volume, haemoglobin, total protein, albumin, and eosinophil counts. Progressive and significant decreases in packed cell volume and haemoglobin were recorded with increasing egg burden, consistent with haemonchosis-associated blood loss anaemia. Total protein and albumin declined markedly in the high-burden group, reflecting protein-losing enteropathy. Eosinophilia was pronounced across all infected groups, indicating active innate immunological response to parasitic antigen. These findings provide objective haematological evidence of production-impacting pathophysiology in helminth-infected sheep and support strategic anthelmintic treatment programmes calibrated to faecal egg count in South West Nigeria. Keywords: helminthiasis, haematology, West African Dwarf sheep, anaemia, Ogun State.