Ectoparasite management in extensively grazed sheep and cattle in New Zealand: Current strategies and future innovations.

Ectoparasites can negatively affect animal health and welfare and incur financial cost to farmers due to losses in animal productivity and performance, and the cost of chemicals and labour used to prevent and/or treat infestations. Therefore, effective management and control are needed to ensure good animal health, welfare and performance. A range of tools are currently available to manage ectoparasites including insecticides, genetics and integrated management strategies. However, emerging challenges such as climate change and chemical resistance are likely to influence how we manage ectoparasites in the future, highlighting the need to evaluate current strategies and develop new approaches. This review focuses on ectoparasites that affect sheep and cattle in New Zealand and provides an overview of (1) their impact on animal health, welfare and productivity and (2) current management strategies and tools, emerging challenges and potential future approaches. The ectoparasite species included in this review are: Sheep ked (Melophagus ovinus), scrotal mange mite (Chorioptes bovis), cattle tick (Haemaphysalis longicornis), biting lice (Bovicola ovis and B. bovis), sucking lice (Linognathus, Haematopinus and Solenopotes species), blowflies (Lucilia cuprina, L. sericata and Calliphora stygia) and the sheep nasal bot (Oestrus ovis). Based on our current understanding, ectoparasites are still an on-going challenge for sheep and cattle farmers in New Zealand and this challenge could increase due to climate change and chemical resistance. However, potential future innovations in ectoparasite management may provide farmers with opportunities to stay in control, including the increasing utilisation of sensor technologies.