Morphological identification of nematode larvae of small ruminants and cattle simplified.

摘要: A simplified system has been developed to facilitate identification of nematode larvae the common nematodes cattle, sheep and goats. Firstly, in addition characteristics conventionally used for (such as shape cranial extremity numbers intestinal cells), lengths infective sheath tails each genus/species are related that Trichostrongylus spp. instead using measurements differentiation. For instance, if mean length tail (the distance extends caudad beyond caudal tip larva) is assumed be "X", then Haemonchus contortus 2-2.7"X", Oesophagostomum from 4-7"X", etc. Secondly, by estimating proportion a larva comprised terminal thin whip-like filament, aided, particularly those L3 species resemble one another closely, such Chabertia ovina venulosum or columbianum. After some practice with it usually necessary measure only two mixed population, whereupon identity most remaining can estimated relation measured, without need further measurements. The keys were found differential larval useful training.