Calderano A.A.,Pos graduacao em Zootecnia |
Gomes P.C.,UFV Vicosa |
Donzele J.L.,UFV Vicosa |
Barreto S.L.D.T.,UFV Vicosa |
And 4 more authors.
Revista Brasileira de Zootecnia | Year: 2012
The objective of this study was to determine the ideal digestible tryptophan:digestible lysine ratio in diets for laying hens from 24 to 40 weeks of age. Two hundred and forty Hy-Line W-36 laying hens at 24 weeks of age were distributed in a completely randomized design, with five treatments, eight replicates and six birds per experimental unit. The digestible tryptophan levels in the experimental diets were 1.57; 1.68; 1.79; 1.90 and 2.01 g/kg, providing ratios of digestible tryptophan:digestible lysine of 0.215; 0.230; 0.245; 0.260 and 0.275. The increase in the levels of digestible tryptophan in the diet linearly improved the feed intake, digestible tryptophan intake, digestible lysine intake, egg production, egg mass, feed conversion per egg mass and utilization efficiency of digestible lysine for eggs mass. There were quadratic effects from the digestible tryptophan levels on egg weight. For the efficiency of utilization of digestible lysine for egg mass, there was better adjustment of the data to the LRP model. The level of digestible tryptophan in the diet from which the plateau occurred was 0.184%. This level corresponded to the intake of 142 mg/bird/day of digestible tryptophan and digestible tryptophan:digestible lysine ratio of 0.252. The ideal digestible tryptophan:digestible lysine ratio recommended in diets for laying hens from 24 to 40 weeks of age is 0.252 (25.2%). ©2012 Sociedade Brasileira de Zootecnia.
Interactions between soybean and weeds in a replacement series system, considering the effects of water stress [Interações entre soja e plantas daninhas em um sistema de série substitutivas, considerando os efeitos do estresse hídrico]
Vivian R.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuária |
Dourado-Neto D.,University of Sao Paulo |
Filho R.V.,University of Sao Paulo |
Silva A.A.,UFV Vicosa |
And 2 more authors.
Planta Daninha | Year: 2013
Due to the increase of water deficiency in many farm regions and its meaning on weed interference, competitive interactions between soybean and three weeds were evaluated under water stress (20 to 40 days after transplanting) and no stress conditions. Three independent experiments were carried out in a growth chamber, being each one composed by the weeds Alternanthera tenella, Tridax procumbens or Digitaria ciliaris, along with the crop, in which soil water condition and plant composition effects were evaluated while in competition. A replacement series system was used, including both monoculture of each species and a mixture with a ratio of 50% between weed and soybean. A completely randomized design was used in factorial arrangement, with treatments distributed in three levels for plant composition factor (soybean and weeds monocultures, in addition to the soybean + weed mixture) and two levels for the water factor (with or without stress), amounting six treatments in each experiment. Soybean dry mass was higher than weed dry mass, when growing without water stress. However, under water stress conditions, the dry mass of soy was reduced in all experiments, mainly in the D. ciliaris comparative experiment. Water restriction was also significant in the plants' photosynthesis reduction in most of the experiments, reducing leaf area duration and efficiency of water use. Analysing all variables shows greater weed tolerance than soybean when submitted to water deficit and with distinct changes of their interactions and mechanism of competition, in each experiment.
Economical analysis of different concentrate levels for dairy crossbred fed sugar cane based diets [Análise econômica da adição de níveis crescentes de concentrado em dietas para vacas leiteiras mestiças alimentadas com cana-de-açúcar]
Costa L.T.,Doutorando do Programa de Pos graduacao em Zootecnia |
da Silva F.F.,UESB Itapetinga |
Veloso C.M.,UFV Vicosa |
Pires A.J.V.,UESB Itapetinga |
And 4 more authors.
Revista Brasileira de Zootecnia | Year: 2011
Sixteen crossbred Holstein × Zebu cows (groups from 1/2 to 3/4 of Holstein × Zebu) at third of fourth lactation were allotted to four 4 × 4 Latin squares to evaluate the economical viability of increasing dietary concentrate level. Cows presented previous milk yield from 2,500 to 3,000 kg, adjusted for 300 days, and grazed pasture during the rainy season, and with 110 days of laction in the beginning of the experimental period. Because of the prices of milk and concentrate during the experiment, it is not interesting to use concentrate in the diets of milk cows fed sugar cane. If the productive and economical aspects toghther and the prices of R$ 0.70 and R$ 0.50 for the milk and the concentrate, respectively are considered, the use of 24% concentrate in the diet is the most interesting option for dairy cows fed sugar cane. © 2011 Sociedade Brasileira de Zootecnia.
Repeatability, correlation and path analysisof physical and chemical characteristics of peach fruits1 [Repetibilidade, correlaçõ es e análise de trilha de characterísticas fÍsicas e quÍmicas de frutos de pessegueiro]
Matias R.G.P.,UFV Vicosa |
Bruckner C.H.,UFV Vicosa |
Carneiro P.C.S.,UFV Vicosa |
Silva D.F.P.,Pos Doutoranda Bolsista PNPD CAPES |
Silva J.O.C.,UFV Vicosa
Revista Brasileira de Fruticultura | Year: 2014
This study aimed to determine the number of measurements necessary to evaluate physical and chemical characteristics of peach fruits, study the relationships between them and their direct and indirect effects on the content of ascorbic acid and total carotenoids. The characteristics skin and pulp color, fruit weight, suture, equatorial and polar diameters, firmness, soluble solids (SS), titratable acidity (TA), SS/TA ratio, ascorbic acid and total carotenoids were evaluated in 39 cultivars of peach and 3 cultivars of nectarine from the orchard of the Universidade Federal de Viçosa. The repeatability coefficient was estimated by ANOVA and CPCOR. Phenotypic correlation coefficients (rf) were estimated and, after the multicollinearity diagnostics, they were unfolded to direct and indirect effects of the explanatory variables on the response variable using path analysis. There was agreement on the magnitude of repeatability coefficients obtained by the two methods; however, they varied among the 14 characteristics. The highest correlations were found between FW, SD, ED and PD. Seven fruits are sufficient to evaluate the physical and chemical characteristics of peach with a correlation coefficient of 90%. The characteristics considered in the path diagrams (b* skin, ho skin, b* pulp, ho pulp, ED, PD, FIR, SS, SS/AT and TC) are not the main determinants of the ascorbic acid. The yellow hue of the pulp (ho pulp) has the potential to be used in indirect selection for total carotenoids. © 2014, Sociedade Brasileira de Fruticultura. All rights reserved.