Sistema de pastejo, rotenona e controle de parasitas em bovinos cruzados: efeito no ganho de peso e no parasitismo

Abstract

Sistema de pastejo, rotenona e controle de parasitas em bovinos cruzados: efeito no ganho de peso e no parasitismo ResumoForam realizados dois experimentos para avaliar o controle de endo e ectoparasitos de bovinos. No primeiro avaliou-se in vitro e, em animais experimentalmente infestados, o efeito da rotenona no carrapato Rhipicephalus(Boophilus) microplus e, no segundo, avaliou-se o efeito do pastejo rotacionado e de tratamentos contra endo e ectoparasitos na carga parasitária e no desenvolvimento de animais naturalmente parasitados. In vitro a rotenona mostrou ação acaricida nas larvas e nas teleóginas, e nas larvas nos animais estabulados. Três tratamentos com endectocida, no período seco, diminuiram significativamente a contagem de ovos por grama de fezes (OPG) e o número de teleóginas, e, aumentou significativamente o ganho médio de peso. Os animais tratados com uma aplicação de levamisol estavam nesse período com médias de OPG intermediárias e significativamente diferentes dos grupos controle e tratados com endectocida. O ganho de peso, entretanto, não diferiu significativamente do grupo controle. No período das águas, os animais tratados com fipronil estavam significativamente menos parasitados por teleóginas, mosca-dos-chifres e por larvas de Dermatobia hominis; e os tratados com rotenona. menos parasitados por mosca-dos-chifres que os animais controle. Diferentemente do esperado, os animais sob pastejo rotacionado estavam no período seco com OPG significativamente maior que os em sistema contínuo. Três tratamentos com endectocida, no período seco, e três tratamentos acaricida com fipronil, na estação chuvosa, diminuíram significativamente o OPG, o número de teleóginas e o de larvas de berne, e proporcionou um aumento significativo de 23 kg de peso vivo em relação aos animais não tratados.Palavras-chave: Bezerros, ectoparasitas, nematoides, sistema de pastejo, rotenona. AbstractPractices for endo and ectoparasite control in beef cattle were evaluated in two independent experiments. First, the effects of rotenone® on Rhipicephalus (Boophilus) microplus ticks were evaluated in vitro and in experimentally infected calves. In the second trial, the effects of grazing systems associated with endo and ectoparasite treatments on parasite burden and weight gain of naturally parasited animals were evaluated. Rotenone showed acaricide action on larvae and engorged ticks during in vitro tests and on larvae in experimentally infected calves. Three treatments with endectocide decreased (P < .05) the number of EPG and ticks and increased (P < .05) the weight gain in the dry season. Animals treated with only one application of levamisole showed EPG intermediate and different (P < .05) from the groups treated with endectocide (lower) and control (higher) in the dry season, but the weight gain obtained with this treatment did not differ from the control group. During the raining season the animals treated with fipronil were significantly less parasited by horn fly, tick and larvae of Dermatobia hominis and the group tre...

Weight gain and control of endo- and ectoparasites of beef heifers treated with allopathic, herbal and homeopathic drugs

“…All groups of animals in this study had a mean (±ep) EPG of approximately 700±180 at the start of the two cycles study; at the completion of both experimental cycles, all groups had a mean EPG of approximately 100, showing a decrease in parasitism with increase in age. Similar results have been reported in previous studies conducted in the same region of Brazil (BIANCHIN et al, 1995(BIANCHIN et al, , 2007CATTO et al, 2009). In the second cycle and over both cycles, the mean EPG in the PC-treated animals was significantly lower than in the animals in any of the other treatment groups.…”

“…The PC treatment was used as a positive control because previous trials have shown significant weight gain in strategically treated animals compared to untreated controls (BIANCHIN et al, 1995(BIANCHIN et al, , 2007CATTO et al, 2009 The animals were supplemented with 200 g/animal/day of protein meal, and all treatments products were used according to the manufacturers' recommendations: Fator C&MC  1,6 g/animal/day; Homeo Bovis Parasitário  4 g/animal/day, Neem cake  4 g/animal/day, Neem oil  10 mL/100 kg, acaricide formulation 1mL/10 kg, Doramectin 1% 1mL/50kg and Moxidectin 10% 1 mL/100 kg . Homeopathic products and neem cake were added to the diet, and the dose of homeopathic products and neem cake was doubled in the second experimental cycle.…”

Gastrointestinal nematode infections do not hinder the development of Simmental X Nellore crossbred calves raised with a nutritionally enhanced diet

“…In this experiment, we evaluated only the effect of GIN infections, since a single dose of fipronil prevented losses caused by ectoparasites. It is therefore difficult to compare our results with those of studies that used products also active against ectoparasites (Bianchin et al, 2007;Catto et al, 2009;Soutello, 2001). For instance, Catto et al (2013) reported that Brangus heifers treated with moxidectin and an acaricide showed lower FECs and tick infestations than untreated animals or animals treated with alternative drugs, which resulted in heifers 22 to 30 kg heavier in the treated group.…”

Atividade biológica de extratos acetato de etila, etanólico e aquoso de timbó (Lonchocarpus floribundus) sobre carrapato bovino

“…(B.) microplus (Tabelas 1 e 2), são semelhantes aos resultados encontrados por Catto et al (2009) Pires et al (2007) que, ao avaliarem a influência da Simarouba versicolor sobre a oviposição do carrapato bovino, observaram que a concentração de 17,2 mg mL -1 inibiu 100% da oviposição e estimou CI 50 de 4,1 mg mL -1 . as cepas utilizadas nos testes biológicos, por estes autores, eram resistentes a este carrapaticida sintético do grupo das formamidinas.…”