Anthelmintic resistance in a dairy cattle farm in the State of Minas Gerais

Abstract

Eighty-four half-blood Gir × Holstein (F1) calves aged six months who were naturally infected by gastrointestinal helminths and maintained in rotational grazing received different anthelmintic treatments. Group A received anthelmintics according to the usual management in the property (eight treatments, seven including a macrocyclic lactone agent). Group B received strategic treatment (ivermectin 3.15%) at the beginning and at the end of the rainy period. Eggs per gram of feces (EPG) counts and genus of larvae from fecal cultures were determined on a monthly basis from April 2002 to December 2003. There was no significant reduction (p > 0.05) in EPG counts in any group after anthelminthic treatment, and the larvae in fecal cultures observed were Cooperia, Haemonchus, Oesophagostomum and a few Trichostrongylus. Cooperia was the most prevalent genus in the first four months of the experiment and Haemonchus in the following months. In 2003, tracer calves were introduced onto the pastures monthly and they showed high nematode burden many times throughout the year, and Cooperia punctata and Haemonchus contortus were the main species identified. The results suggest that there is anthelminthic resistance in this farm, mainly to macrocyclic lactones, and the development of immunity by crossbred animals was vital to reduce nematode burden.Keywords: Cattle, anthelmintic resistance, Cooperia, macrocyclic lactone, Haemonchus. ResumoOitenta e quatro bezerras meio sangue Gir × holandês (F1) com seis meses de idade, naturalmente infectadas por helmintos gastrintestinais e mantidas em pastejo rotacionado receberam diferentes tratamentos anti-helmínticos. O grupo A recebeu anti-helmínticos segundo manejo empregado na propriedade (oito tratamentos, sete com produtos à base de lactonas macrocíclicas). O grupo B recebeu tratamento estratégico (ivermectina 3,15%) no inicio e final de período chuvoso. Mensalmente, no período de abril de 2002 a dezembro de 2003, foram realizadas contagens de ovos por grama de fezes (OPG) e coproculturas. Não houve redução significativa (p > 0,05) nas contagens de OPG em nenhum dos grupos após os tratamentos anti-helmínticos, e as larvas encontradas na coprocultura foram Cooperia, Haemonchus, Oesophagostomum e poucos Trichostrongylus, com predominância de Cooperia nos quatro meses iniciais e Haemonchus nos meses seguintes. No ano de 2003, bezerros traçadores foram alocados mensalmente nos pastos, apresentando altas cargas parasitárias na maioria dos meses do ano, sendo as principais espécies identificadas: Cooperia punctata e Haemonchus contortus. Os resultados indicam que os nematódeos da fazenda apresentam resistência anti-helmíntica, principalmente às lactonas macrocíclicas, e o desenvolvimento de imunidade foi primordial para reduzir a carga parasitária dos animais mestiços.Palavras-chave: Bovinos, resistência anti-helmíntica, Cooperia, lactonas macrocíclicas, Haemonchus.

Solanum paniculatum L. Leaf and Fruit Extracts: Assessment of Modulation of Cytotoxicity and Genotoxicity by Micronucleus Test in Mice

“…For each treatment, groups of five animals were orally treated with three different doses (100, 200, or 300 mg=kg) of S. paniculatum ELE or EFE and simultaneously cotreated with mitomycin C (MMC) (C 15 Statistical analyses. In order to analyze the antimutagenic activity of S. paniculatum ELE and EFE, the frequency of MNPCEs in the treated groups was compared to the results of the positive control group by one-way analysis of variance, and a value of P < .05 was taken as the criterion of statistical significance.…”

“…These alkaloids include jurubebina, jubebine, and solanine. 14,15 The phytochemical analysis of S. paniculatum extracts showed that the components or contents vary by location of plant parts. Fructose, glucose, and galactose were detected in the fruits, 16 and solanine was isolated from its roots and stems.…”

Helminthiasis control in calves raised in a hot Semi-arid area

“…Para evitar esto se debe de priorizar a los becerros de ambos sexos hasta los 24 meses de edad y a las hembras en el periparto. Ambas categorías están mucho más susceptibles a los helmintos (38,39,40) . Solo en el 33.3 % de las granjas trataron a las vacas en periparto.…”

“…Este género tiene una prevalencia más alta entre los pequeños rumiantes, mientras que el género Cooperia sp. tiende a ser el más frecuente entre el ganado en Brasil (35,40) . Sin embargo, Haemonchus spp.…”

“…En un estudio previo en Betim, Minas Gerais, también se observó la resistencia a la ivermectina y la doramectina de los géneros Haemonchus (72 %) y Cooperia (85 %) (46) . Los géneros Haemonchus y Oesophagostomum también mostraron resistencia a las lactonas macrocíclicas en un estudio en Teófilo Otoni, Minas Gerais, en que estos AH eran los más usados para el control de NG en las granjas evaluadas (40) . Los resultados de otro estudio también confirman la predominancia de Haemonchus spp.…”