Prevalence and Infection Intensity of Haemonchus contortus in Sheep and Goats Slaughtered during the Late Dry Season in Zaria, Nigeria

Abstract

Haemonchosis remains one of the most economically important helminth infections limiting small ruminant productivity in tropical and subtropical regions. This study determined the prevalence and intensity of Haemonchus contortus infection in sheep and goats slaughtered during the late dry season in Zaria, Kaduna State, Nigeria. A cross-sectional abattoir-based design was employed, involving 196 small ruminants comprising 98 sheep and 98 goats. Abomasa were collected immediately after slaughter, and adult worms were recovered using standard post-mortem worm count techniques. Identification was based on morphological features, and worm burdens were categorized into light, moderate, and heavy infections. Data were analysed using descriptive statistics and Chi-square tests to compare infection patterns between species. Findings revealed that light infection was the predominant category in both sheep (78.6%) and goats (70.4%), while moderate infection occurred at low levels in sheep (6.1%) and goats (3.1%). No heavy infections were recorded in either species. A higher proportion of goats (26.5%) were uninfected compared to sheep (15.3%). Statistical analysis indicated no significant difference in infection distribution between sheep and goats (p > 0.05). The overall pattern suggests widespread exposure to H. contortus but with relatively low worm burdens during the late dry season. The absence of heavy infections may reflect seasonal constraints on larval survival and transmission dynamics. These findings highlight the importance of season-specific parasite control strategies and provide baseline epidemiological data for the improvement of helminth management in small ruminants in northern Nigeria.