Targeted supplementation with bioactive plants sustainably improves goat health and decreases antiparasitic drug use on smallholder farms

Goats play a significant role in farming communities in semi-arid tropical areas with limited cropping capacity; however, production is limited by endoparasites, especially gastrointestinal nematodes (GINs). Control of GINs is typically mediated by anthelmintic drugs, but can be costly or ineffective where anthelmintic-resistant GINs are present. To manage anthelmintic resistance and improve herd health at lower costs, farmers can implement Targeted Selective Treatment (TST) strategies to treat animals based on performance or health traits. The study aimed to quantify the impacts of plant-based interventions on goat health, nutrition, and parasite infections when applied in a targeted selective feeding regime under an arid environment. Here we trialled a farmer-led TST scheme using a worm diagnostic tool for sheep and goats based on checking five points on the animal body; nose (purulent discharge), eye (colour of the conjunctivae), jaw (subcutaneous pitting oedema), back (body scoring condition, and tail (mild to severe diarrhoea). This method, termed the Five Point Check or FAMACHA, was used to periodically measure goat health, with anthelmintic interventions provided only to individuals in poor condition. In addition to TST with anthelmintic, a plant-TST was trialled on 50% of the farms where goats in borderline or poor condition were supplemented with local bioactive plants (Viscum rotundifolium L. or Terminalia sericea). Plant-TST treatment significantly reduced worm burden (P < 0.001) from a mean of 485 EPG pre-treatment to 269 EPG post-treatment, with 75% of goats having a FEC of ≤ 400 EPG. Further, goats under plant-TST had significantly improved health outcomes (p < 0.001 FAMACHA scores) compared to TST-anthelmintic. Goats under plant-TST were 46.6% less likely to require any anthelmintic treatment. Plant- and anthelmintic-TST had a similar FEC reduction (55.5% and 52.5%, respectively). Plant-TST offers a low-resource means to sustainably manage GINs in in goats in semi-arid conditions.