Characterisation of Gastrointestinal Parasite Burdens and Risk Factors in Small Ruminants Across Agro-Ecological Zones of Nigeria

This study characterises gastrointestinal parasite burdens and identifies risk factors associated with high parasite loads in sheep and goats across three contrasting agro-ecological zones of Nigeria, contributing evidence for zone-specific parasite management recommendations. Gastrointestinal nematode parasitism is the most economically important health constraint for small ruminants in sub-Saharan Africa, and its epidemiology varies substantially with climate, management, and animal breed. Zone-specific characterisation is necessary for designing effective control programmes that account for these differences. This study conducts cross-sectional parasite surveys across 144 farms in the Sudan Savanna (Sokoto and Katsina States), Guinea Savanna (Niger and Kwara States), and Humid Forest (Edo and Delta States) zones. Faecal samples from 720 sheep and goats are analysed by modified McMaster technique for egg counts, and larval cultures identify dominant nematode genera. FAMACHA conjunctival scores, body condition scores, blood parameters, and farm management data are collected simultaneously. Mixed model analysis identifies risk factors for high faecal egg counts. Findings reveal significantly higher egg counts in the humid forest zone (geometric mean 843 eggs per gram) compared to Sudan Savanna (418 epg) and Guinea Savanna (621 epg), consistent with climate effects on larval survival. Haemonchus contortus dominates across all zones at 65 to 74 percent of larvae. Kids and lambs under 6 months show 2.8-fold higher egg counts than adults. Anthelmintic resistance to benzimidazoles is detected in 62 percent of farms using larval development assay. The study recommends zone-differentiated FAMACHA-based targeted selective treatment protocols.

Keywords: gastrointestinal parasites, small ruminants, agro-ecological zones, FAMACHA, Nigeria.