Extracting Protostrongylus spp. larvae from bighorn sheep feces

First-stage larvae of Protostrongylus spp. were more numerous in the core of bighorn sheep (Ovis canadiensis canadiensis) pellets than near the surface. As a result, only 22% could be extracted from whole pellets and the numbers collected did not reflect the total number of larvae present in samples. Crushing semi-dried pellets yielded seven times as many larvae and numbers collected were correlated with totals present. The use of tissue, in addition to a screen filter in a beaker extraction method, produced a cleaner sample and did not affect larval collection or the correlation. By comparison, most first-stage larvae of Parelaphostrongylus tenuis from white-tailed deer (Odocoileus virginianus) were near the surface of fecal pellets where they may be removed readily by water.