Sheep and goat response to T. colubriformis
Ethiopian researchers studied host response to artificial challenge with Teladorsagia colubriformis worm larvae by drenching half of twenty-eight small ruminants (sheep = 14) and (goat = 14) with 10,000 T. colubriformis L3. The remaining half served as the untreated controls. Fecal egg count (FEC) was recorded from day-0 through day-56. At the end of experiment, the animals were euthanized and the worms were recovered from the intestines.
FEC at various days post infection was insignificantly higher in goats than in sheep. The worm burden was significantly higher in infected goats than in infected sheep despite the goats having received an equal dose of L3. The first fecal eggs were detected at day-18 post infection in infected goats. However, in infected sheep, the eggs were first observed at day-21 post infection.
The shorter prepatent period, higher FEC in almost all sampling periods, and higher total worm count were the characteristic of infection in goats when compared to the sheep. This suggested the relatively lower worm burden under natural conditions in goats may be due to their feeding behavior rather than their inherent resistance.
C. colubriformis often appears as co-pathogen with other gastrointestinal worms under natural conditions. It is probably the second most important nematode to Haemonchus contortus in terms of distribution and magnitude in tropical and subtropical regions.
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