Susceptibility of high and low producer dairy goats to single experimental infection with Trichostrongylus colubriformis

Culled dry dairy goats, which differed in their level of production in previous lactations, received a single infection with Trichostrongylus colubriformis. The objectives of the study were twofold. First, the study aimed at examining the ability of dairy goats to develop an immune response to trichostrongyle infection and the associated cellular changes developing within the intestinal mucosa. Second, a comparison between animals differing in their level of production was assessed, in order to determine whether these differed in their susceptibility to infection. No difference occurred in egg excretion, worm burden and local inflammatory cell responses between high (HP) and low (LP) producer dairy goats, in contrast to observations in previous studies. Because their nutrition was controlled and milk production absent in the goats employed in the present study, these results suggest that any genetic component associated with the selection of HP and LP goats had little influence on the development of acquired resistance to T. colubriformis. The analysis of the relationship between different cell types in the mucosa and some characteristics of the worm population show that eosinophils are negatively related to worm burden. Also, a role is suggested for mast cells and globule leukocytes in the modulation of egg excretion.