Composición y calidad de la leche en función de la etapa de lactancia y de la paridad

The purpose of this work was to evaluate the relationship among lactation order and days in milking with milk production, composition and somatic cells count (SCC) from Holstein cows and also verify the efficiency of "California Mastitis Test” (CMT) to detect high scores of SCC. Milk samples were collected from the Experimental Farm of Iguatemi located in Maringa, Parana State, from 2008 to 2009. Regression analyzes were performed by a computer system R (2009) in order to verify the behavior of production and milk components as a function of days of lactation order and using the mixed model methodology, considering animal and day of milk control as random. To evaluate the efficiency of CMT test in detecting high SCC was considered negative binomial distribution for the response variable, because it is data that exhibit over dispersion, using the methodology of generalized linear models. It was found that milk production increases and milk fat decreases by the lactation order. Milk protein increases with the days in milking because milk production is decreased. It was concluded that milk production and quality are closely connected to the lactation order and days in milking and CMT performed on farm is positively linked with CCS.El objetivo de este estudio fue evaluar la relación entre el orden y los días de lactancia con la producción, composición y conteo de células somáticas (CCS) en leche de vacas Holstein, así como comprobar la eficacia de la prueba California para Mastitis (CMT) detectando alto CCS. Se tomaron muestras de leche del rebaño de la Hacienda Experimental de Iguatemi, Maringá-PR, en un periodo comprendido entre 2008 y 2009. Fueron realizados análisis de regresión utilizando el programa estadístico R (2009) con el fin de verificar el comportamiento de la producción y los componentes de la leche en función de los días y orden de lactancia utilizando la metodología de modelos lineares mixtos, considerando el animal y día de control lechero como aleatorios. Para evaluar la eficacia de la prueba de CMT para detectar alto CCS se consideró distribución binomial negativa para la variable respuesta, ya que los datos mostraron sobredispersión utilizando la metodología de modelos lineales generalizados. Se encontró que a medida que la producción de leche aumenta, el porcentaje de grasa en la leche disminuye, siendo diferente en cada orden de lactancia. El porcentaje de proteína aumenta con el periodo de lactación, mientas disminuye la producción. Se concluye que la producción y la calidad de la leche están estrechamente relacionadas con el orden y los días de lactación, la prueba CMT tiene relación positiva con el CCS

A new analysis of the GJ581 extrasolar planetary system

We have done a new analysis of the available observations for the GJ581 exoplanetary system. Today this system is controversial due to choices that can be done in the orbital determination. The main ones are the ocurrence of aliases and the additional bodies - the planets f and g - announced in Vogt et al. 2010. Any dynamical study of exoplanets requires the good knowledge of the orbital elements and the investigations involving the planet g are particularly interesting, since this body would lie in the Habitable Zone (HZ) of the star GJ581. This region,for this system, is very attractive of the dynamical point of view due to several resonances of two and three bodies present there. In this work, we investigate the conditions under which the planet g may exist. We stress the fact that the planet g is intimately related with the orbital elements of the planet d; more precisely, we conclude that it is not possible to disconnect its existence from the determination of the eccentricity of the planet d. Concerning the planet f, we have found one solution with period $\approx 450$ days, but we are judicious about any affirmation concernig this body because its signal is in the threshold of detection and the high period is in a spectral region where the ocorruence of aliases is very common. Besides, we outline some dynamical features of the habitable zone with the dynamical map and point out the role played by some resonances laying there.Comment: 12 pages, 9 figure

Effect of essential oils from Eucalyptus on the growth of aflatoxigenic species

In Brazil, Eucalyptus species has been cultivated as source of energy and cellulose. They represent the most important cultivated forest in the country. In production areas, the leaves from the trees decay on the soil as green fertilizer. In this study were evaluated pure and blends of essential oils from different species of eucalyptus trees grown in Brazil for antifungal activity against aflatoxigenic species Aspergillus flavus and A. parasiticus. These fungal species can grow and contaminate grains during the storage period under high r.h. conditions, with an eventual production of aflatoxins. Antifungal activity was evaluated by the radial growth measurement of the fungi inoculated on maize meal extract agar basic medium. The eucalyptus oils were evaluated in a contact assay and a fumigant assay using pure and blended oils. Six concentrations of pure and blended oils were evaluated at the following doses: 0, 2, 4, 16, 32 and 84 μL per 20 mL of fungi culture medium. Fungal inocula from conidia suspensions containing 106 spores/mL was inoculated by a needle. Glass Petri dishes were incubated for 9 days at 28°C (± 0.3°C) in the dark. Antifungal activity was observed in all pure and blended oils, in different concentrations of contact and fumigant assay, for both fungi. Eucalyptus stageiriana oil and E. stageiriana + the hybrid E. grandis x E. urophylla oils blend controlled the total fungal growth at the lowest dose (20 μL). Keywords: Essential oil; Eucalyptus spp.; Aspergillus flavus; Aspergillus parasiticus; Antifungal activity