La correspondencia de Valencia : diario de noticias : eco imparcial de la opinión y de la prensa: Año XXXVI Número 15812 - 1913 Octubre 11

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 200

Bovine genetic resistance effects on biological traits of Rhipicephalus (Boophilus) microplus

AbstractThis study aimed to verify the influence of bovine genetic resistance on biological traits of the Rhipicephalus (Boophilus) microplus tick. Genetic resistance or susceptibility was determined according to breeding values for tick counts, predicted using a dataset of 9007 Hereford and Braford (Hereford×Zebu) bovines naturally infested and raised under extensive production systems in southern Brazil. From a total of 974 Braford heifers born in 2008, 20 were classified as genetically tick-resistant and 20 classified as genetically tick-susceptible, and used to obtain the ticks samples used in this study. The 40 heifers were exposed to four subsequent artificial infestations with approximately 20,000 larvae at 14-day intervals. From the 19th to 23rd day of each infestation tick counts were performed on the left body side of the heifers. Engorged ticks were manually collected on the day of highest observed burden after each infestation. Tick counts on susceptible heifers were 5.5, 10.5, 11.1 and 6.9 times larger than on resistant heifers, respectively, after the first, second, third and fourth artificial infestations. In the third infestation, ticks from resistant heifers showed lower egg production index (P<0.0001) than ticks from susceptible heifers. In the fourth infestation, ticks from susceptible group showed higher egg mass weight (P<0.05) and nutrient index (P<0.0001) than ticks from resistant heifers. Tick initial weights showed a positive association with egg production index in susceptible heifers (P<0.05) and a negative association in the resistant group (P<0.05), suggesting a host defense mechanism that reduces the conversion efficiency of ingested blood to eggs in engorged ticks from resistant cattle. This shows that bovine genetic tick resistance, in addition to affecting the number of ticks carried by the animals, also affected the egg mass weight, egg production and nutrient indexes of ticks. The results of the present study imply that the selection of resistant animals could be used as a strategic tool for tick control in production systems, reducing infestation levels on cattle and environment

Transmissão transovariana de Babesia bovis em Boophilus microplus: obtenção de cepa de carrapato livre de Babesia spp. Babesia bovis transovarian transmission in Boophilus microplus: obtention of a Babesia free tick strain

O presente trabalho objetivou o estudo de parte do ciclo da Babesia bovis no seu hospedeiro invertebrado, o carrapato Boophilus microplus. Analisou-se a capacidade de infeccção e transmissão transovariana de B. bovis em partenóginas de B. microplus, alimentadas em bovinos portadores e enfermos por esse protozoário. No 18º dia após a infestação, coletaram-se partenóginas diretamente do corpo dos bovinos e teleóginas após o desprendimento natural, a partir do 21º dia. Todos os grupos foram incubados a 27ºC e umidade relativa superior a 70%. No 5º dia após o início da postura, realizou-se o exame de hemolinfa a fim de diagnosticar a infecção dos ínstares por B. bovis. A ausência de infecção detectada no exame de hemolinfa foi confirmada posteriormente com o teste biológico, revelando que partenóginas não transmitem B. bovis transovarianamente. Esses resultados oferecem uma técnica simplificada para a obtenção de cepas de carrapatos livres de B. bovis.<br>In this experiment part of the life cycle of Babesia bovis in its invertebrate host, the tick Boophilus microplus was studied. In order to evaluate the capacity of infection and transmission of B. bovis were collected semi-engorged females of B. microplus fed on carrier and ill bovines. In the 18th day after infestation, semi-engorged females were collected directly from bovine bodies and after 21st day engorged females dropped on the ground. All the collected groups were incubated at 27°C and relative humidity greater than 70%. At the 5th day of oviposition the diagnosis was made by direct examination of haemolymph smears. The biological test reveled that B. bovis transovarial transmission doesn't happer in semi-engorged females. The results offer a simple techique to obtain strains of ticks free of B. bovis

Fontes e doses de nitrogênio para mamoneira de porte baixo no sistema plantio direto Nitrogen fertilizers and rates in castor bean hybrids under no-till system

O cultivo de mamona em grandes áreas se tornou possível com a introdução recente de híbridos de porte baixo que possibilitam a mecanização total das práticas agrícolas, inclusive na colheita. No entanto, as informações sobre práticas agrícolas a serem empregadas, quando da utilização desses híbridos, ainda são escassas, principalmente, no que se refere ao manejo da adubação nitrogenada. O trabalho teve como objetivo estabelecer as doses de nitrogênio mais adequadas para híbridos de mamona de porte baixo no sistema plantio direto. O experimento foi conduzido por dois anos agrícolas (2005/2006 e 2006/2007) na Fazenda Experimental Lageado, UNESP, Botucatu (SP). Os tratamentos foram constituídos por duas fontes de nitrogênio (sulfato de amônio e uréia) e por quatro doses (0, 30, 60 e 120kg ha-1 de N) aplicadas em cobertura aos 20 dias após a emergência, sendo utilizado o híbrido Savana. A adubação nitrogenada de cobertura promoveu aumento de produtividade ao híbrido de mamona no sistema plantio direto. A produtividade de grãos não diferiu entre as fontes de N utilizadas. A dose média de N calculada que proporcionou a maior produtividade de grãos foi de 88kg ha-1 na safra 2005/2006 e 100kg ha-1 na safra 2006/2007.<br>The castor bean crop in large areas has become possible with the recent introduction of short stature hybrids that allow the complete mecanization of agricultural practices, including the harvest. However, when hibrids are used, the information about agricultural practices to be employed, are still very poor, especially, with regard to management nitrogen fertilization. The aim of this study was to evaluate the effect of nitrogen sources and doses in castor bean hybrids under no-till system in summer crop. The experiment was conducted for two crop years (2005/2006 and 2006/2007). The experiment design was a randomized blocks in 2x4 factorial design with four replications. The treatments comprised the combination of two nitrogen sources (ammonium sulfate and urea), with four doses of nitrogen (0, 30, 60 and 120kg ha-1 of N) surface applied 20 days after emergence, plus a control. The hybrid Savana was utilized. The nitrogen fertilization increased productivity of the castor bean under no-till system. The grain yield wasn't influenced by the nitrogen source utilized. The average rate calculated that allowed the maximum grain yield was 88kg ha-1 in the 2005/2006 crops and 100kg ha-1 in the 2006/2007 crops

Adubação fosfatada e épocas de cultivo na composição química de sementes de cultivares de feijoeiro

Phosphorus is a limiting nutrient in common bean grain yield and may influence the chemical composition of seeds. The aim was to assess the effects of phosphorus fertilization and planting dates ('water' and 'dry') in the seeds chemical composition of two dry bean cultivars. A field experiment was carried out in Botucatu (SP) in a randomized block design with five replications. Two dry bean cultivars 'Carioca Precoce' e 'IAC Carioca Tybatã' were evaluated in growing 'water' and 'drought' in six levels of P2O5 (0, 30, 60, 90, 120 and 150kg ha-1) applying superphosphate at planting row. It was assessed seed samples to determine the levels of N, P, K, Ca, Mg, S, Cu, Mn, Fe, Zn, total and reducing sugar and protein. The phosphorus in the soil alters the seeds chemical composition, increasing contents of P and decreasing Ca and Cu contents. The K and Fe contents showed minimum point at a level of 69.9 and 66kg ha-1 of P2O5, respectively. It was observed that occurred increase in contents of N, P, and protein of seeds in the growing season 'drought'. The cultivar 'Carioca Precoce' showed higher N content and protein of seeds than 'IAC Carioca Tybatã'. There is interaction between cultivar and growing season for the content of S, Mn, Fe, Ca, Mg, Cu, total and reducing sugars.O fósforo (P) é um nutriente limitante na produtividade do feijoeiro e pode influenciar na composição química de sementes. O trabalho objetivou avaliar os efeitos da adubação fosfatada e de épocas de cultivo ('águas' e 'seca'), na composição química de sementes de duas cultivares de feijoeiro. O experimento foi realizado em Botucatu (SP), no delineamento de blocos ao acaso com cinco repetições. As cultivares de feijão 'Carioca Precoce' e 'IAC Carioca Tybatã' foram avaliadas no cultivo 'das águas' e 'da seca' sob seis doses de P2O5 (0; 30; 60; 90; 120 e 150kg ha-1) com aplicação de superfosfato triplo no sulco de semeadura. Amostras de sementes foram analisadas para determinação dos teores de N, P, K, Ca, Mg, S, Cu, Mn, Fe, Zn, açúcar total e redutor e proteína. A adubação fosfatada alterou a composição química das sementes, incremento nos teores de P e redução de Ca e Cu. Os teores de K e Fe apresentam ponto de mínima nas doses de 69,9 e 66kg ha-1 de P2O5, respectivamente. O cultivo na época 'da seca' favorece os teores de N, P e proteínas das sementes. A cultivar 'Carioca Precoce' apresenta maior teor de N e proteínas nas sementes em relação a 'IAC Carioca Tybatã'. Há interação cultivar e época de cultivo para o teor de S, Mn, Fe, Ca, Mg, Cu, açúcares totais e redutores.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Estadual de Londrina Centro de Ciências Agrárias Departamento de AgronomiaUniversidade Estadual Paulista Departamento de Produção VegetalUniversidade Estadual Paulista Departamento de Produção Vegeta