Nematode parasitism affects lying time and overall activity patterns in lambs following pasture exposure around weaning

We investigated the effects of gastrointestinal nematode (GIN) challenge on activity in first season grazing lambs naturally exposed to two different levels multispecies GIN infections. Ewes and their twin-born were turned-out graze permanent pasture enclosures contaminated with previous year, thereby exposing them overwintering strongyle larvae. Animals low parasite exposure group (LP) dewormed monthly 0.2 mg ivermectin (Ivomec® vet, oral suspension) per kg body weight, whereas those high (HP) left untreated. At weaning, allocated one out four groups based weight sex (HPE, n = 15; HPR, LPE, 14; LPR, 14), nearby non-contaminated ley similar size. Activity patterns monitored from day ?7, i.e. 7 days pre-weaning, until 49, 49 post-weaning, by fitting all IceQube sensors (IceRobotics). Body was weekly ?21, faecal samples at 7, 35 for egg counts (EPG) using McMaster-technology a validated Droplet Digital PCR protocol determine composition. All statistical analyses performed R studio, mixed models repeated measures. In data analyses, recordings treated as period, generating total eight periods. Average daily lying time had significant interaction between period (P 0.0013), animals HP having 101 ± 31 min shorter compared LP. Motion Index (MI; absolute value 3-D acceleration) 0.0001) lower average MI Both gain EPG significantly (P<0.0001) LP during course study. The molecular investigation showed that predominantly infected Teladorsagia spp., combined proportions Haemonchus spp. conclusion, this study shows around weaning affected moderate This indicates there is potential use automated behaviour diagnostic tool detection parasites even infection levels.