Renius Mello

CARACTERÍSTICAS PRODUTIVAS E QUALITATIVAS DE HÍBRIDOS DE MILHO PARA PRODUÇÃO DE SILAGEM

O objetivo do presente trabalho foi determinar as isotermas de sorcao das espigas de milho para diversas condicoes de temperatura e umidade relativa do ar e ajustar diferentes modelos matematicos aos dados experimentais. Para obtencao do teor de agua de equilibrio higroscopico das espigas de milho foi utilizado o metodo estatico, em câmaras com temperatura controlada, contendo no seu interior dessecadores com solucoes salinas saturadas. A temperatura variou entre 10 e 50°C e a umidade relativa entre 0,11 e 0,84 (decimal). As amostras foram pesadas periodicamente, sendo o equilibrio higroscopio alcancado quando a variacao da massa das amostras foi igual ou inferior a 0,01 g. Os modelos matematicos recomendados pela ASAE foram ajustados as dados experimentais. Para a avaliacao do grau de ajuste de cada modelo considerou-se a magnitude do coeficiente de determinacao ajustado, erros medio relativo e estimado, e a verificacao do comportamento da distribuicao dos residuos. Conclui-se que a higroscopicidade da espiga de milho segue a mesma tendencia da maioria dos produtos agricolas e que os modelos de Chung-Pfost Modificado, Halsey Modificado e Oswin Modificado representam adequadamente o fenomeno.

Características fenológicas, produtivas e qualitativas de híbridos de girassol em diferentes épocas de semeadura para produção de silagem

The objective of this study was to estimate the effect of three sowing dates: October (early), November (normal) and December (late), on the phenological, yield and qualitative traits of four sunflower hybrids: Rumbosol-91 (forage), M-734 (double purpose), C-11 (double purpose) and BRS-191 (grain) grown for silage making. A 4 x 3 factorial treatment combination (four hybrids x three sowing dates) was allocated in a randomized block design with four replications. The October sowing brought about longer cycle, higher plant height, and smaller seed head diameter and contribution due to the prevailing climatic conditions of lower temperature, insolation and photoperiod during the crop growth period. The Rumbosol-91 and BRS-191 hybrids sowed in November showed higher lodging plus stalk breaking proportion of about 49.6 and 65.7%, respectively. The BRS-191 and M-734 hybrids sowed in December showed higher biomass yields of 39.71 and 43.76 t ha-1 fresh matter and 11.31 and 11.41 t ha-1 drymatter, respectively. While the CP content increased, the NDF, ADF and ADL contents decreased from the stem, to the leaf and to the head plant fractions. The whole plant DM values ranged from 23.2% in the Rumbosol-91 hybrid sowed in November to 47.9% in the C-11 hybrid sowed in December, indicating that the hybrids have differentiated moisture retention capacity at similar physiologic maturity of the culture (R-9 phase). The CP values ranged from 7.0 to 15.7%, an evidence of the high protein content of the culture. The ADL values of the whole plant ranged among 6.5 to 12.4%, with lowest values for the M-734 hybrid sowed in December and C-11 hybrid sowed in October. The M-734 hybrid sowed in December has better relationship among phenology, yield and bromatological composition, traits required for the making of high quality silage.

Fracionamento dos carboidratos e proteínas de silagens de milho, sorgo e girassol

This work evaluates and characterizes the carbohydrates and proteins fractions of corn, sorghum and sunflower silages. The purpose was to supply composition data that make it possible to maximize use of foods and optimize animal performance. Two corn (Zea mays) hybrids, DKB-215 and DKB-344; sorghum (Sorghum bicolor) hybrids, Ambar and AG-2005; and sunflower (Helianthus annuus) hybrids, Rumbosol and M-734; were evaluated. Sunflower silage showed the lowest total carbohydrates (TC) and B2 (cellulose and hemicelluloses) values and the highest content of C (lignin and fiber associated lignin). Corn silages showed higher non-fiber carbohydrates (NFC), A+B1 (soluble sugars + starch and pectin) and TC together sorghum silage while the last one showed higher B2 due to higher stem contribution. There were differences between hybrids of sunflower for TC, when Rumbosol showed higher contents than M-734, due to the aptitude of these materials, forage and grain respectively. The sunflower silage showed higher crude protein (CP) and protein fractions. There were no differences between hybrids for CP and protein fractions values.

Resíduo proveniente do beneficiamento do feijão (Phaseolus vulgaris L.) em rações para vacas em lactação: consumo, digestibilidade, produção e composição do leite e eficiência de alimentação

This work was carried out with the objective to evaluate the effect of replacement of soybean meal by common bean (Phaseolus vulgaris L.) residue in rations for milking cows on the following variables: intakes and total apparent digestibilities of nutrients, milk production and composition and feeding efficiency. Twelve Holstein cows were randomly assigned to three 4 ´ 4 balanced latin square design. The animals was fed ad libitum total mixed rations, which contained 0; 13; 26 and 39% of raw common bean residue in the concentrate, in substitution of soybean meal. Dry matter (DM), organic matter (OM), non fiber carbohydrates (NFC) and total digestible nutrients intakes were linear depressed by the increasing levels of common bean residue in the concentrate. Neutral detergent fiber (NDF) and indigestible neutral detergent fiber (iNDF) intakes were not affected by the diets and crude protein (CP) and ether extract (EE) intakes presented cubic behavior. The digestibility coefficients (DC) of DM, OM, EE and NDF were not affected by the diets while DC of CP and NFC presented linear decreasing and increasing behavior, respectively. Milk production and composition (fat, protein, lactose, non fat and total dry extracts), as expressed in kg/day, presented linear decreasing for the increasing levels of substitution. No difference was observed for feeding efficiencies among diets. The inclusion of common bean residue in the diets prejudiced the performance of the animals.

Perfil metabólico e desenvolvimento da glândula mamária de novilhas leiteiras sob manejo para crescimento compensatório

Objetivou-se avaliar o efeito do manejo para crescimento compensatorio e da suplementacao com ionoforo sobre o perfil metabolico e o crescimento da glândula mamaria de novilhas leiteiras. Foram utilizadas 20 novilhas Pardo-Suicas puras, com peso inicial de 200 kg e 5 meses de idade. Os tratamentos foram arranjados em esquema fatorial 2 × 2 e os animais foram alocados aleatoriamente em cada uma das combinacoes. O fator 1 consistiu dos sistemas de alimentacao (convencional e crescimento compensatorio) e o fator 2, da utilizacao ou nao de ionoforo (200 mg de monensina/animal/dia). Os animais do sistema convencional receberam alimentacao ad libitum, enquanto os do sistema para crescimento compensatorio foram submetidos a um manejo nutricional com dois periodos distintos: periodo de restricao energetica (90 dias, P1) e periodo de realimentacao (60 dias, P2). Novilhas submetidas ao sistema crescimento compensatorio apresentaram maior concentracao de nitrogenio ureico (N-ureico) plasmatico e menor razao DNA:RNA no tecido mamario. Quando analisados dentro de periodo, os niveis de lipoproteinas de alta densidade (HDL) aumentaram no periodo de realimentacao, enquanto os de N-ureico diminuiram. Alem da alteracao nos niveis de N-ureico, o balanco energetico ao qual as novilhas em crescimento compensatorio foram submetidas ocasionou aumento no teor dos acidos graxos nao-esterificados. Houve reducao nos niveis de glicose sanguinea dos animais em crescimento compensatorio no periodo de realimentacao. A suplementacao com ionoforo proporciona menor concentracao de acidos graxos nao-esterificados durante o periodo de realimentacao.

Composição corporal e exigências nutricionais de macrominerais de bovinos Caracu selecionados e Nelore selecionados ou não para peso ao sobreano

Body composition and net and dietary requirements of macrominerals (Ca, P, Mg, Na and K) of genetically selected Caracu (CaS) and Nellore (NeS) for yearling weight (378 days of age) as well as of ordinary Nellore (control; NeC) were investigated in this trial. Fifty-six young bulls averaging 18 months of age were used. Twelve animals were slaughtered after an adaptation period and were used as reference. The 44 remaining animals, 16 NeS, 16 CaS and 12 NeC, with initial average body weight (BW) of 392, 421 and 337 kg, respectively, were distributed to a completely randomized design in a 3 x 2 factorial arrangement (genetic group [NeS, CaS and NeC] and feeding regime [restricted and ad libitum]). Animals were fed a diet with a 50:50 forage (corn silage):concentrate ratio and were slaughtered after reach 4 mm of subcutaneous fat thickness measured by ultrasound. After slaughter, body parts of all animals were weighed and sampled. Samples were then freeze-dried, treated with ether to remove fat, ground and contents of macrominerals determined. Estimation of body retained macrominerals were done by regressing the logarithm of Ca, P, Mg, Na and K body content on the logarithm of empty body weight (EBW). Net macrominerals requirements for 1 kg of EBW gain were obtained by derivation of the prediction equations. There was a significant effect of genetic group on the body content of the studied macrominerals. Body contents and requirements of all macrominerals followed EBW and increased as EBW of animals increased.