Nematódeos de ruminantes em pastagem com diferentes sistemas de pastejo com ovinos e bovinos

Abstract

Resumo -O objetivo deste trabalho foi avaliar os efeitos de diferentes sistemas de pastejo, com ovinos e bovinos, sobre a quantidade de larvas no estágio L 3 de nematódeos de ruminantes. O delineamento experimental foi inteiramente ao acaso, em arranjo fatorial com quatro sistemas de pastejo e quatro períodos de rotação de pastagem. A duração do experimento foi de 91 dias, com sistema rotacionado (7 dias de ocupação e 21 de descanso), em 8 ha de Panicum maximum cv. Tanzânia. Foram avaliados os sistemas de pastejo: alternado, simultâneo e isolado, com ovinos e com bovinos. Foram utilizados 20 bovinos (mestiços), 30 cordeiros e 15 ovelhas adultas (raça Santa Inês). As amostras do capim, para recuperação e identificação dos nematódeos, foram realizadas semanalmente no pré e pós-pastejo dos piquetes. Na média geral de todos os manejos, a ordem decrescente de número de larvas foi: Haemonchus spp., Trichostrongylus spp., Oesophagostomum spp., Strongyloides spp. e Cooperia spp. Correlações médias foram encontradas entre as quantidades de larvas L 3 no pré e pós-pastejo. Com o aumento do número de rotações, houve aumento no grau de contaminação da pastagem pelas larvas, independentemente do sistema adotado. O sistema de pastejo simultâneo foi o que apresentou maior controle da carga parasitária de Haemonchus spp. na pastagem de capimtanzânia.Termos para indexação: Panicum maximum, forma de vida livre, nematódeo gastrintestinal. Ruminant nematodes in pasture under different grazing systems with sheep and cattleAbstract -The objective of this work was to evaluate the effect of different grazing management systems on the parasitic nematode load (L 3 larvae) in ruminants. The experimental design was completely randomized, in a factorial arrangement with four grazing systems and four rotations. The experimental period was 91 days, in a rotational system (7 days of occupation and 21 of days rest), in 8-ha pasture cultivated with Panicum maximum cv. Tanzânia. The different management systems evaluated were: alternate, simultaneous and isolate whit cattle and sheep. Twenty mixed breed cattle, 30 lambs and 15 ewes were used (Santa Inês breed). Grass samples were collected for recovery and identification of L 3 -larvae every week, during pre and postgrazing. In all systems, the decreasing order the number of identified larvae was Haemonchus spp., Trichostrongylus spp., Oesophagostomum spp., Strongyloides spp., and Cooperia spp. Mean correlations were found between L 3 -larvae numbers in pre and postgrazing. Increasing rotation caused increase in the degree of infection irrespectively of the system used. The simultaneous system had the best control on the parasitic load of Haemonchus spp., on Tanzania grass pasture.

Effect of alternate and simultaneous grazing on endoparasite infection in sheep and cattle

“…Actually, although grazing together or separately could influence the grazing habits, this was not within the scope of our investigation and therefore was not measured. Nevertheless, the results from Torres et al (2009), who studied the parasitic nematode load on the same paddocks during this trial, corroborates our results: they observed that ALT paddocks were more heavily infested (for overall parasites and especially for Haemonchus spp.) than SIM paddocks.…”

“…Fernandes et al (2004) also found that sheep grazing alone had higher FEC than did mixed species grazing. The reduction in parasite infection in the pasture with mixed grazing (ROCHA et al, 2008;TORRES et al, 2009) was probably due to the different grazing habits of cattle, as previously described.…”

“…This hypothesis, i.e. that certain parasite species common to several types of domestic animals have developed more specific relationships of parasitism with certain host species (AMARANTE et al, 1997;ROCHA et al, 2008;TORRES et al, 2009), was shown in the present study to be true, at least for the relationship between sheep and Haemonchus spp., given that lower larval counts in fecal cultures and lower FEC were seen when mixed grazing systems were used (Figure 1 and Table 2). This is important, because Haemonchus is the most important internal parasite for sheep worldwide, and it presents increasing drug resistance and high pathogenicity.…”

“…Hence, no animals had been using this pasture before this experiment. However, grass samples from the experimental area were collected for recovery and identification of L 3 -larvae before the first grazing week, and the mean parasite load detected was 4.56 larvae/kg of dry matter (TORRES et al, 2009). Additional information about parasitic nematode load in this pasture can be found in TORRES et al (2009).…”

Avaliação do efeito de microrganismos probióticos sobre a sanidade de bezerros desmamados e bezerras em fase de aleitamento

“…A incidência e distribuição dos helmintos apresentam variações regionais e sazonais, dependendo de vários fatores como regime pluvial, ecossistema, manejo, raça e idade dos animais. No Brasil, as verminoses predominantes de bovinos criados em pastagens naturais estão apresentadas no Tabela 1 (TORRES, 2009;CRAIG,2008;DORCHIES, 2008;SOUZA et al 2008;ARAUJO et al, 2006;REPOSSI-JUNIOR et al, 2006;STROMBERG;GASBARRE, 2006;CATTO et al, 2005;LIMA, 2004;RAMOS et al, 2004;RIBEIRO et al, 2003;GIRÃO;LEAL, 2002;PIMENTEL-NETO;FONSECA, 2002;GUIMARÃES et al 2000;SOUZA et al 2000;EMBRAPA, 1999;VICENTE et al, 1997;BIANCHIN, 1996;GECHEVARRIA et al, 1993;ARAUJO et al, 1992;CHARLES;FURLONG, 1992;LIMA, 1989;CARNEIRO et al, 1987;COSTA et al, 1986;FURLONG;ABREU;VERNEQUE, 1985 CRAIG, 2008;DORCHIES, 2008;SOUZA et al 2008;ARAUJO et al, 2006;REPOSSI-JUNIOR et al, 2006;STROMBERG;GASBARRE, 2006;CATTO et al, 2005;LIMA, 2004;RAMOS et al, 2004;RIBEIRO et al, 2003;…”