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Experimental infection of calves with Haemonchus placei and Haemonchus contortus: Assessment of parasitological parameters

Fávero, Flávia Carolina, Buzzulini, Carolina, Cruz, Breno Cayeiro, Felippelli, Gustavo, Maciel, Willian Giquelin, Salatta, Bruna, Teixeira, Weslen Fabricio Pires, Soares, Vando Edésio, Oliveira, Gilson Pereira de, Lopes, Welber Daniel Zanetti, Costa, Alvimar José da
Veterinary parasitology 2016 v.217 pp. 25-28
Haemonchus contortus, Haemonchus placei, Holstein, calves, egg production, females, helminths, laboratory animals, larvae, males, necropsy, neonates, pastures, prepatent period, reflexes, sheep, viability
The present study evaluated the viability and possible effects of Haemonchus contortus infections in experimentally prime infected calves, comparing them to infections by Haemonchus placei. Ten male Holstein newborns were used. All calves were individually weighed for subsequent group formation, in which two animals were kept as a control group, inoculated with water (GI); four animals were inoculated with 10,000 third stage (L3) Haemonchus contortus larvae (GII); and the remaining four calves were inoculated with 10,000 third stage (L3) H. placei larvae (GIII). All experimental animals were necropsied on the 42nd day after inoculation. Based on results obtained by the present study, it can be concluded that bovine calves were susceptible to infections by both Haemonchus species (placei and contortus). H. contortus presented an inferior pre-patent period when compared to H. placei. No significant difference (P>0.05) was observed between Haemonchus burdens recovered from both infected groups (GII and GIII). Moreover, H. contortus females maintained an egg production rate similar to H. placei females in young animals, which can contribute to pasture contamination by both Haemonchus species. This could possibly lead to negative reflexes on helminth control based on a mixed pasture with bovines and ovines, especially when it involves younglings.