Prevalence and tick loads in Nguni cattle reared in different environmental conditions across four provinces of South Africa

Background and Aim: Ixodid ticks are among the most economically important ectoparasites of livestock in tropical and sub-tropical countries. Although South African Nguni cattle are adapted to harsh environments, their resistance to ticks and tick-borne diseases in different climatic conditions is unknown. The objective of the current study was to compare tick load and prevalence among Nguni cattle under different environmental conditions.
Materials and Methods: Tick counts were conducted monthly under natural challenge over two years on 586 Nguni cattle located at ARC Roodeplaat and Loskop farms (warmer climate), Mukhuthali Nguni Community, and University of Fort Hare farms (cooler climate). Data were analyzed using the GLM (Generalised Linear Models) procedure of Statistical Analysis System (SAS) fitted location (farm), sex, year, either month or season and age of animal as a covariate.
Results: The following tick species (relative prevalence) were observed: Amblyomma hebraeum (42%), Rhipicephalus evertsi evertsi (22%), Rhipicephalus (Boophilus) spp. (16%), Rhipicephalus appendiculatus (11%), H. marginatum (5%), and Rhipicephalus simus (4%). Tick infestation was significantly affected by location, season, year, month of the tick counting, and age of the animal. Loskop farm had the highest tick counts (μ = 30.69) and showed the largest variation in tick count. Higher tick counts were also observed in the hot dry (September to November) and hot wet (December to February) seasons compared to the other seasons. Amblyomma hebraeum was the dominant tick species across all four farms followed by R. evertsi evertsi. The most favored tick attachment sites were the perianal region (under the tail head), perineum and belly body locations.
Conclusion: These results provide useful information for the development of appropriate control strategies for ticks and tick-borne diseases in these provinces of South Africa. Further work is required to investigate the feasibility of genetic improvement for tick resistance.