Depicting latent variables considering different pig genetics and nutritional plans in crossbred pigs

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.(AU)

Perfil ectoparasitário em bovinos leiteiros mestiços da microrregião de São João Del-Rei, Minas Gerais, Brasil / Profile of ectoparasites from crossbreed dairy cattle in the microregion of São João Del-Rei, state of Minas Gerais, Brazil

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.

The aim of the present study was to evaluate the profile of ectoparasites infesting dairy cattle and calves from properties located in the micro region of São João del-Rei, State of Minas Gerais, Brazil, as well as its seasonal variations, in order to provide information that aids the control of such parasite infestations. A total of 224 dairy cows and 112 calves, belonging to 15 different rural properties, were evaluated by observation and manual palpation for counting parasites (botfly, ticks, and larvae). Dermatobia hominis botfly exhibited a prevalence of 64.29% on dairy cows, whereas the tick Rhipicephalus (Boophilus) microplus and the fly Musca domestica showed 59.38% and 43.30% of prevalence, respectively. Among calves, the prevalences of ectoparasites were 32.14% for D. hominis, 29.46% for R. (B.) microplus and 31.15% for M. domestica. Prevalence and abundance of all ectoparasites were higher in adults (p < 0,001). Only adults were used in the seasonal comparisons because data were more representative and trustable. Prevalences of D. hominis and M. domestica were significantly different between the dry and rainy season, being D. hominis exhibiting lower values during the dry season (p < 0.001) and M. domestica during the rainy season (p < 0.001). Suggestively, the seasons influence parasite infestation rates. It is recommended performing periodical and long term studies on parasitology and epidemiology, to establish strategies for sanitary management that minimizes the degree of parasite infestation and improve the productivity in this microregion.

Perfil ectoparasitário em bovinos leiteiros mestiços da microrregião de São João Del-Rei, Minas Gerais, Brasil / Profile of ectoparasites from crossbreed dairy cattle in the microregion of São João Del-Rei, state of Minas Gerais, Brazil

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.(AU)

The aim of the present study was to evaluate the profile of ectoparasites infesting dairy cattle and calves from properties located in the micro region of São João del-Rei, State of Minas Gerais, Brazil, as well as its seasonal variations, in order to provide information that aids the control of such parasite infestations. A total of 224 dairy cows and 112 calves, belonging to 15 different rural properties, were evaluated by observation and manual palpation for counting parasites (botfly, ticks, and larvae). Dermatobia hominis botfly exhibited a prevalence of 64.29% on dairy cows, whereas the tick Rhipicephalus (Boophilus) microplus and the fly Musca domestica showed 59.38% and 43.30% of prevalence, respectively. Among calves, the prevalences of ectoparasites were 32.14% for D. hominis, 29.46% for R. (B.) microplus and 31.15% for M. domestica. Prevalence and abundance of all ectoparasites were higher in adults (p < 0,001). Only adults were used in the seasonal comparisons because data were more representative and trustable. Prevalences of D. hominis and M. domestica were significantly different between the dry and rainy season, being D. hominis exhibiting lower values during the dry season (p < 0.001) and M. domestica during the rainy season (p < 0.001). Suggestively, the seasons influence parasite infestation rates. It is recommended performing periodical and long term studies on parasitology and epidemiology, to establish strategies for sanitary management that minimizes the degree of parasite infestation and improve the productivity in this microregion.(AU)