Efficacy of amitraz acaricide footbaths against cattle and goat tick infestations on sites in Highveld and Lowveld regions of Zimbabwe

Abstract

Ticks cause significant economic losses in the Zimbabwean livestock sector. Conventional control methods such as plunge dipping or hand spraying are costly, water-intensive, and often impractical, particularly during dry seasons. This study evaluated the efficacy of amitraz acaricide footbaths in reducing tick infestations on cattle and goat across three sites in the Highveld and Lowveld regions of Zimbabwe between February and October 2023. Tick infestation levels were compared between livestock managed using conventional tick control methods (plunge dipping complemented by tick grease application in Lowveld, or complete body hand spraying in the highveld) and livestock managed using footbathing complemented by tick grease application. A total of 21,500 ticks representing eight species were collected on 48 cattle and 48 goats. The effects of treatment and season on tick infestation were tested using zero-inflated negative binomial regression models, which accounted for excess zeros and overdispersion in tick count data. In the Lowveld, footbaths significantly reduced cattle tick infestation by the 3 most abundant tick species: <i>Ripicephalus microplus</i> (40% reduction), <i>Amblyoma. hebraeum</i> (51%) and <i>R. decoloratus</i> (43%). Significant reductions in infestation rate by <i>A. hebraeum</i> (70%) and <i>R. decoloratus</i> (68%) was also observed on goats from the same Lowveld site. In the Highveld goat site, footbath significantly reduced infestation by <i>A. hebraeum</i> (91%), <i>R. appendiculatus</i> (46%), <i>R. decoloratus</i> (49%) and <i>R. evertsi evertsi</i> (82%) on goats. In the Highveld cattle site where the conventional method to control ticks was complete body hand spraying, footbathing was not more effective than the conventional method for controlling <i>R. decoloratus</i>, the dominant tick species. Tick counts varied seasonally, with <i>Rhipicephalus</i> subgenus <i>Boophilus</i> ticks most abundant on cattle, during the dry season in Lowveld and during the rainy season in Highveld). Similarly, footbath did not perform better than conventional methods to control Hyalomma tick species (i.e. <i>H. truncatum</i> and <i>H. rufides</i>) found in goats and cattle in the Highveld and Lowveld sites. The study also shows patterns of seasonal variation (i.e. difference between the rainy season and the dry season) in ticks infestation rates that differ depending on site, host species and tick species. These findings suggest that acaricide footbaths provide a practical, low-cost alternative for tick control in both cattle and goats, especially in areas with limited water resources.