ABSTRACT
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)
Subject(s)
Animals , Cattle , Ectoparasitic Infestations/veterinary , Parasite Load/veterinary , Parasite Load/statistics & numerical data , SeasonsABSTRACT
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.
Subject(s)
Animals , Cattle , Parasite Load/statistics & numerical data , Parasite Load/veterinary , Ectoparasitic Infestations/veterinary , SeasonsABSTRACT
The intense selection process for economic traits conducted by the poultry breeding programs has been caused several changes in broiler meat quality. A database belonging to a selection program of a broiler male line was used to estimate heritability and genetic correlations for feed conversion ratio and meat quality traits, which were: initial and final pH, lightness, drip loss, thawing loss and shear force. Two-trait analyses were performed and the components of co(variance) and genetic parameters were determined using the Bayesian approach and the GIBBS3F90 software. The heritability estimate found for feed conversion ratio (0.52) showed high influence of direct additive genetic effects on the expression of this trait; therefore, this trait is able to respond to selection. The genetic correlation estimates obtained (-0.50 to 0.33) were indicative of important associations between feed conversion ratio and meat quality traits. The selection to improve feed conversion ratio may cause injury in greater or lesser degree for L*, drip loss (DL), thawing loss (TL) and shear force (SF) in broilers. It is recommended the monitoring of consequences of feed conversion ratio used as selection criteria or meat quality traits in broilers, due to its unfavorable indirect selection for these variables in this population. Breeding methods for efficiency improvements in broilers feed are suggested, which also benefit sensorial and functional properties of the meat.
Subject(s)
Animals , Meat/analysis , Animal Husbandry/methods , Chickens/genetics , Bayes TheoremABSTRACT
The intense selection process for economic traits conducted by the poultry breeding programs has been caused several changes in broiler meat quality. A database belonging to a selection program of a broiler male line was used to estimate heritability and genetic correlations for feed conversion ratio and meat quality traits, which were: initial and final pH, lightness, drip loss, thawing loss and shear force. Two-trait analyses were performed and the components of co(variance) and genetic parameters were determined using the Bayesian approach and the GIBBS3F90 software. The heritability estimate found for feed conversion ratio (0.52) showed high influence of direct additive genetic effects on the expression of this trait; therefore, this trait is able to respond to selection. The genetic correlation estimates obtained (-0.50 to 0.33) were indicative of important associations between feed conversion ratio and meat quality traits. The selection to improve feed conversion ratio may cause injury in greater or lesser degree for L*, drip loss (DL), thawing loss (TL) and shear force (SF) in broilers. It is recommended the monitoring of consequences of feed conversion ratio used as selection criteria or meat quality traits in broilers, due to its unfavorable indirect selection for these variables in this population. Breeding methods for efficiency improvements in broilers feed are suggested, which also benefit sensorial and functional properties of the meat.(AU)