Persistent challenge with Trichostrongylus colubriformis and Haemonchus contortus larvae does not affect growth of meat-breed lambs suppressively treated with anthelmintics when grazing

Losses caused by gastrointestinal nematode infections in Dorper lambs under two nutritional status

“…In the field, the major difficulty encountered is in maintaining uninfected control groups as worm-free. It has been demonstrated that persistent challenge with H. contortus and T. colubriformis infective larvae does not affect the growth of grazing, meat-breed lambs when suppressively treated with effective anthelmintics, indicating that the use of suppressively treated sheep could be a valid substitute for worm-free lambs in field experiments (DEVER et al, 2015). However, the absence of anthelmintics with a high degree of efficacy has been a problem when designing studies that require comparisons between infected and noninfected control groups in the field.…”

Influence of seasonality and biological activity on infection by helminths in Cantabrian bear

“…The phenomenon of “self-curation” has been observed in some livestock species, characterized by a decrease in the fecal egg counts of certain nematodes, mainly trichostrongylids, before the spontaneous elimination of adults from the gut and after the ingestion of new infective stages during a heavy challenge infection ( Foster & Elsheikha, 2012 ; Dever et al, 2015 ). However, the exact mechanisms underlying this phenomenon are not fully understood.…”