Resistance of beef cattle of two genetic groups to ectoparasites and gastrointestinal nematodes in the state of São Paulo, Brazil

The resistance to infestations by ectoparasites and infections by gastrointestinal nematodes was studied in 45 animals (males and females) of two genetic groups: purebred Nelore (NI, n=28) and Three-Cross (1/2 Angus+1/4 Canchim+1/4 Nelore - TC, n=17). The animals were monitored for 24months, during which they were left to graze in tropical pastures without receiving treatment for parasites. Each month the animals were examined for infestations by external parasites, to count the numbers of cattle ticks Rhipicephalus microplus with diameter greater than 4.5mm present on the left side, horn flies (Haematobia irritans) present in the lumbar region and botfly larvae (Dermatobia hominis) present on the entire body. The H. irritans counts were performed with the aid of digital photographs. At the time of examination, fecal samples were collected to count the eggs per gram (EPG) and to perform coprocultures, and peripheral blood samples were drawn to determine the packed cell volume (PCV) and to count the eosinophils. For statistical analysis, the count data were transformed into log10 (n+1), where n is the number of parasites. For PCV, significant effects (P<0.05) were found for collection month (CO), genetic group (GG) and gender (SX), with means and respective standard errors of 41.5±0.65% for the NI animals, 39.3±0.83% for the TC, 41.5±0.72% for the females and 39.3±0.77% for the males. Regarding the eosinophil counts, only the effect of sex was significant (P<0.01), with means and respective standard errors of 926.0±46.2/μL, for males and 1088.0±43.8/μL of blood, for females. The NI animals presented lower mean counts for all the external parasites compared to the TC animals (P<0.01). For ticks, the transformed means followed by standard errors for the NI and TC animals were 0.06±0.01 and 0.34±0.02, while for horn flies these were 0.92±0.05 and 1.36±0.06 and for botfly larvae they were 0.05±0.03 and 0.45±0.05, respectively. The average EPG values were only influenced by CO (P<0.01). The coprocultures revealed the presence of the following endoparasites: Haemonchus spp., Cooperia spp., Oesophagostomum spp. and Trichostrongylus spp., the last in smaller proportion. There were no significant differences between the genetic groups for the endoparasite loads, except for Cooperia spp., which were present in greater number (P<0.05) in the NI group. The results obtained in this experiment confirm previous findings of greater susceptibility of the Nelore breed to Cooperia spp. and high resistance to ectoparasites. © 2013 Elsevier B.V.

Avaliação comparativa de duas formulações anti-helmínticas em caprinos naturalmente infectados

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nemátodeos gasrointestinais de bovinos de corte com resistência à moxidectina

Pós-graduação em Biologia Geral e Aplicada - IBB

Avaliação da atividade de Aretmisia annua L., Melia azedarach L. e Trichilia claussenii C. sobre nematódeos gastrintestinais de ovinos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nematodioses de ovinos e caprinos mantidos em pastagens no oeste da Bahia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Epidemiologia das infecções por nematódeos gatrintestinais em ovinos criados em Botucatu

Pós-graduação em Medicina Veterinária - FMVZ

Fauna helmintológica de ovinos provenientes da microrregião de Jaboticabal, estado de São Paulo, Brasil

This study evaluated the prevalence and counting parasitism of different species of helminths of sheep from the micro-region of Jaboticabal of Sao Paulo state. For this, 66 animals naturally infected, four to 36 months of age, raised in pasture, were selected. The results of necropsy revealed the presence of seven genera and 12 species with the following prevalence and mean count: Haemonchus contortus: 100.0% (2947.2); Trichostrongylus colubriformis: 90.9% (3048.8); Cooperia curticei: 56.0% (256.5); Oesophagostomum columbianum: 48.4% (36.0); Cooperia punctata: 30.3% (94.5); Trichostrongylus axei: 22.7% (26.5); Strongyloides papillosus: 19.6% (83.0), Haemonchus contortus (L4): 7.5% (17.2), Cooperia pectinata: 10.6% (12.9), Trichuris ovis: 10.6 % (0.6); Cooperia spatulata 4.5% (0.3); Capillaria bovis: 4.5% (0.1). The mean parasitism of helminthswas 6524.7 per animal. Haemonchus contortus (adults and L4) and Trichostrongylus colubriformis corresponded to 45.4% and 46.7% of the average worm burden totally, respectively. Based in the results obtained in this study, can be concluded that the two most abundant species of helminths and important, the micro-region of Jaboticabal are Trichostrongylus colubriformis and Haemonchus contortus, and these two species amounted to 92.1% of the distribution percentage of helminths collected from all animals. These results demonstrate the importance of conducting a counts of eggs per gram of feces (EPG) in the herds of this region when FAMACHA is used on a particular property, since this method control does not allow to diagnostic the damage/clinical signs in animals infected by T. colubriformis, because this specie does not have hematophagism habit on animals.

Prevalência de nematódeos em ovinos (Ovis aries) pertencentes a diferentes microrregiões do estado de São Paulo, Brasil

Pós-graduação em Medicina Veterinária - FCAV

Gastrointestinal nematode infections in sheep raised in Botucatu, state of Sao Paulo, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diagnosis of anthelmintic resistance in cattle in Brazil: a comparison of different methodologies

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Anthelmintic efficacy of ivermectin and abamectin, administered orally for seven consecutive days (100 mu g/kg/day), against nematodes in naturally infected pigs

The present study aimed to evaluate ivermectin and abamectin, both administered orally in naturally infected domestic swine, as well as analysing if the EPG (eggs per gram of faeces) values were equivalent with the ivermectin and abamectin efficacy obtained by 'parasitological necropsies. The animals were randomly selected based on the average of three consecutive EPG counts of Strongylida, Ascaris suum and Trichuris for experiment I, and of Strongylida and Trichuris for experiment II. After the random draw, eight animals were treated, orally, during seven consecutive days with 100 mu g/kg/day ivermectin (Ivermectina (R) premix, Ouro Fino Agronegocios), eight other animals were treated, orally, during seven consecutive days with 100 mu g/kg/clay abamectin (Virbamax (R) premix - Virbac do Brasil Industria e Comercio Ltda.), and eight pigs were kept as controls. EPG counts were performed for each individual animal at 14th day post-treatment (DPT). All animals (control and treatment) were necropsied at the 14th DPT. The results from both experiments demonstrate that both ivermectin and abamectin, administered orally for a continuous period of seven days, at a daily dosage of 100 mu g/kg, were highly effective (>95%) against Hyostrongylus rubidus, Strongyloides ransomi, Ascaris suum and Metastrongylus salmi. Against Oesophagostomum dentatum, abamectin presented over 95% efficacy against both evaluated strains, while ivermectin reached other strain as resistant. Regarding T. suis, both ivermectin and abamectin were effective (efficacies >90%) against one of the tested strains, while the other one was classified as resistant. Furthermore, the EPG values were equivalent with the ivermectin and abamectin efficacy obtained by parasitological necropsies. (C) 2014 Elsevier Ltd. All rights reserved.

Supplementation with protected fat to manage gastro-intestinal nematode infection in Santa Ines sheep

This experiment aimed to determine the influence of supplementation with protected fat on nematode infections in periparturient sheep or sheep in their final stage of pregnancy. Fifty Santa Ines ewes received 200 g of concentrate/animal/day, mineral salt and water and were grouped according to their weight, hematocrit and the number of eggs per gram of feces (EPG). Two diets were used: a control treatment and a treatment consisting of supplementation with 30 g/animal/day of protected fat in the concentrate. Three monthly evaluations were performed over a total of 84 days of testing. The variables analyzed were weight, body condition, EPG and coprocultures; blood tests were performed for the determination of packed cell volume, hemoglobin concentration and total plasma protein, and leukograms and eosinophil counts were performed. For weight and hemoglobin concentrations, interactions were observed between diet and collection date (P<0.05); body condition, total plasma protein, packed cell volume and total leukocytes did not differ statistically among treatments (P> 0. 05) but did differ by collection day (P <0.05). The EPG and eosinophil counts did not differ statistically by either diet or collection date (P>0.05). The genus Haemonchus was predominant, followed by the genera Cooperia, Trichostrongylus and Oesophagostomum. The protected fat did not decrease EPG and did not improve the blood parameters of infected sheep.

Avaliação do desempenho e características relacionadas ao grau de infecção por helmintos de bovinos da raça nelore

Pós-graduação em Ciência e Tecnologia Animal - FEIS