Tick infestations cause significant welfare impacts in sheep in the UK, both directly through feeding and indirectly through the diseases they transmit.
Tick welfare impacts on sheep range from mild irritation to severe systemic disease depending on burden and pathogen transmission. Lambs are most vulnerable, with heavy tick loads causing anaemia and tick paralysis. Louping ill, transmitted by ticks, causes a fatal neurological disease in naive sheep exposed to infected ticks - vaccination is available but not universally used. Tickborne fever suppresses immunity for weeks after infection, predisposing sheep to secondary infections. Regular checking of sheep in tick-prone areas, combined with strategic acaricide treatment and vaccination, substantially reduces the welfare burden of tick-borne disease.