| seasonal fluctuations of nematode populations in breeding ewes and lambs. | the seasonal changes in nematode populations of a flock of sheep in the montreal area were determined using serial fecal egg counts, fecal culture of larvae and necropsy worm counts. it was found that ostertagia spp.,nematodirus spp., trichostrongylus agei, trichostrongylus spp. and chabertia ovina over-wintered on pasture and could initiate patent infections the following spring. the development of populations of h. contortus was typical of that seen with most of the other species and was chara ... | 1973 | 4265556 |