Experimental and Natural Parasite Infestations in Ewes

Genetic selection of animals resistant to gastrointestinal strongyles is a promising alternative to the use of anthelmintics. This book presents the results of a three-year experiment conducted at the Fedatest breeding station. Blanc du Massif Central ewe lambs were selected based on the intensity of fecal excretion following experimental infestation. A group of resistant animals (low excretors) and a group of susceptible animals (high excretors) were established. They were monitored under natural infestation conditions on the same pasture for 3 years, then experimentally re-infested. The objective of this thesis is to study the first generation of selected animals and the cohabitation of susceptible and resistant animals. Fecal egg excretion is significantly lower in resistant ewes, but only during the first year of natural infestation, in an environment where parasite pressure is moderate. No major impact of resistant or susceptible status on zootechnical parameters (fertility, prolificacy, mortality, and lamb growth, etc.) was reported.

Pagina's: 60, Paperback, Our Knowledge Publishing