STUDIES ON CAPRINE RESPONSIVENESS TO NEMATODIASIS - SEGREGATION OF MALE GOATS INTO RESPONDERS AND NONRESPONDERS

Eighty-three 2-4-year-old intact male goats exposed to a combination o f artificial and natural challenge were segregated into responders and non-responders by ranking of weekly faecal egg counts (FECs). Retrosp ective analysis of samples over a 15-week-period showed responders had a statistically lower mean FEC than non-responders. Estimates of repe atability between consecutive egg counts were significant in both grou ps. The 6 top responders and bottom non-responders were subsequently g iven an artificial trickle challenge with Teladorsagia circumcincta an d Trichostrongylus vitrinus. Mean faecal egg output was significantly lower in responders than non-responders. Peripheral eosinophil numbers following challenge were significantly greater in responder than non- responder goats. Abomasal and intestinal worm burdens were considerabl y lower in responders, with evidence of retardation of worm developmen t compared to non-responders. Both abomasal and jejunal tissue eosinop hil numbers were significantly higher in responders, although there wa s no difference in mucosal mast cell or globule leucocyte numbers. The se results suggest that under temperate climatic conditions, it is pos sible to segregate male goats into responders and non-responders on th e basis of simple parasitological criteria.