No abstract

The present study provides the first evaluation of the endoparasite profile in dairy cattle from the microregion of São João del-Rei, Minas Gerais, Brazil, including seasonal variations in parasitic infections. Fecal samples were collected directly from rectum of 123 dairy cows and 160 calves on 15 farms. These were kept in insulated boxes and sent for immediate analysis. Using eggs per gram of feces (EPG) we found the following prevalences: Strongyloidea 43.5%, Moniezia sp. 7.6% and both Strongyloides sp. and Trichuris spp. 2.2%, in dairy cows. In calves, the prevalence was Strongyloidea 50.9%, Moniezia sp. 5.6% and Strongyloides sp. 1.9%. The third-stage larvae recovered from coprocultures from cows and calves consisted mainly of Cooperia spp., Haemonchus spp. and Ostertagia spp. EPG counts were significantly higher in calves. Regarding seasonality, the EPG counts and prevalence of Moniezia sp. tended to be higher in the dry period, whereas those of Strongyloidea were higher in the rainy season. Evidence suggests that parasite control and prophylaxis were inadequately managed on the farms studied here. The present parasitological profile correlates with those found by other similar studies, indicating that the main problem is still the inadequate management of parasite control and prophylaxis by farmers.

Breeding and geneticsFull-length research article Depicting latent variables considering different pig genetics and nutritional plans in crossbred pigsABSTRACT -We aimed to reduce the dimensionality of quantitative traits in pigs applying factor analysis. Quantitative variables were collected, and the factor analysis extracted five factors with biological meaning related to performance, carcass quality, carcass yield, meat quality, and initial pH. These factors were posteriorly used as dependent variable to evaluate the effects of genetic groups (Piau, Duroc, and Pietrain crossbreds), nutritional plans (low, medium and high lysine levels) and sex. An interaction effect between genetic group and sex was observed in performance, in which Duroc crossbred showed the greatest scores. The Pietrain genetic group showed greater values of carcass quality compared with Duroc and Piau, while Piau crossbred pigs had greater values for meat quality compared with Pietrain and Duroc. A greater carcass yield was observed in Pietrain crossbred compared with Duroc pigs. Pigs fed under low lysine level had the lowest performance values. Carcass yield was affected by nutritional plans, in which the medium lysine level showed the greatest values. Meat quality was improved by the nutritional plan with high lysine level compared with the low lysine level. Initial pH showed increased means when using nutritional plans with low and medium lysine levels in diet composition. With regard to sex effects, a greater carcass quality was found for gilts compared with barrows. The reduction of the data dimensionality allowed the joint evaluation of genetic group, nutritional plan, and sex based on new latent variables that represented the original dataset under easier framework based on factors' biological interpretation.

Objetivou-se avaliar o perfil ectoparasitário em bovinos leiteiros da microrregião de São João del-Rei -MG, Brasil, bem como suas variações sazonais, a fim de fornecer dados que auxiliem o controle da infestação destes parasitos. Foram examinadas 224 vacas lactantes e 112 bezerros distribuídos em 15 propriedades rurais, através da contagem de todos os ectoparasitos (moscas, carrapatos e bernes) presentes sobre o animal. Nas vacas lactantes a prevalência de ectoparasitos foi de 64,29% para larvas de Dermatobia hominis, 59,38% para carrapatos Rhipicephalus (Boophilus) microplus e 43,30% para Musca domestica. Nos bezerros as prevalências foram de 32,14% para larvas de D. hominis, 29,46% para R. (B.) microplus e 31,25% para M. domestica. A prevalência e abundância de todos os ectoparasitos foram maiores nos adultos (p < 0,001). Somente indivíduos adultos foram considerados nas análises de sazonalidade devido a melhor representatividade e confiabilidade dos dados. As prevalências de D. hominis e M. domestica diferiram significativamente entre as estações seca e chuvosa, sendo que D. hominis apresentou menores percentuais durante a estação seca (p < 0,001) e M. domestica durante a estação chuvosa (p < 0,001). O rebanho leiteiro da microrregião de São João del-Rei -MG se mostrou altamente infestado por ectoparasitos de comum ocorrência, i.e., D. hominis, Musca domestica e R. (B.) microplus. A sazonalidade sugestivamente exerce influência sobre as taxas de infestação. Recomenda-se a realização de estudos epidemiológicos parasitológicos periódicos em longo prazo, a fim de estabelecer estratégias de manejo sanitário que minimizem o grau de infestação dos bovinos na região. Palavras-chave: controle; infestação; manejo; produção animal; ruminante.