Drivers of heartwater losses in South Africa: a Poisson and negative binomial regression approach

As global and South African efforts to increase livestock production for economic and sustainable development, face challenges from heartwater, a tick-borne disease, resulting in substantial losses and food security concerns. This study examines factors determining heartwater-associated mortalities in cattle and sheep using Poisson and Negative Binomial regression models based on survey data from 296 farmers across South Africa’s provinces. Results showed farmers with Bos taurus and composite/crossbreed cattle who practised genetic resistance after blocking, reduction of control, tetracycline use, and blocking in thicket and fynbos biomes had higher cattle mortalities. Being in a forest biome while controlling ticks frequently reduced cattle mortalities from heartwater disease. In sheep, being in the forest biome while using other/infrequent tick control, reducing control, and blocking with tetracycline led to heartwater-associated mortalities. Conversely, farm experience and frequent tick control (once or twice a month or quarterly) resulted in a decline in heartwater-associated mortalities in sheep. The study recommends integrated strategies prioritizing resistant breeds, judicious acaricide/antibiotic use through rotation to delay resistance, and adaptive management tailored to ecological and species-specific dynamics. This approach can incorporate government and municipal collaboration with research and agricultural sections in developing biome-specific tick-borne disease control strategies.