André Luiz Rodrigues Magalhães

Reparametrização do modelo baseado na lei de superfície para predição da fração digestível da fibra em detergente neutro em condições brasileiras

Objetivou-se avaliar as estimativas da fracao digestivel da FDN em bovinos com base na aplicacao do conceito de Lei de Superficie. Adotou-se a estrutura basica do modelo de predicao sugerido pelo sistema nutricional NRC (2001), cujos parâmetros basicos sao: fator de protecao da lignina sobre os carboidratos da parede celular vegetal (FPL) e coeficiente de digestibilidade da fracao potencialmente digestivel da FDN (CDFDNP). Dois diferentes conjuntos de estimativas desses parâmetros foram avaliados. No primeiro caso, denominado Modelo Weiss (MW), empregaram-se 0,75 e 0,667 como estimativas de CDFDNP e FPL, respectivamente. No segundo caso (Modelo Corrigido - MC), adotou-se 0,85 como estimativa de FPL. As estimativas de CDFDNP foram obtidas por meio de meta-analise de dois experimentos conduzidos com vacas em lactacao e quatro conduzidos com bovinos em crescimento e terminacao, assumindo valores de 0,67 e 0,835, respectivamente. Os procedimentos de comparacao entre modelos foram conduzidos sobre dois experimentos, um para cada categoria animal. Para vacas em lactacao, verificou-se similaridade entre modelos no tocante ao erro medio de predicao (EMP), de +1,07 e +1,05 pontos percentuais de FDN digestivel para MW e MC, respectivamente. Para bovinos em crescimento e terminacao, verificou-se menor EMP para MC (+0,42 pontos percentuais) em comparacao ao MW (-6,64 pontos percentuais). A direcao da flutuacao dos erros de predicao constituiu a principal limitacao de MC, possivel reflexo de interferencias ambientais sobre a interacao carboidratos lignina na parede celular. Embora o MC permita a obtencao de estimativas mais verossimeis que MW, a incorporacao de metodos biologicos para estimacao da fracao potencialmente digestivel da FDN pode incrementar a acuracia do processo de predicao.

Morphometry and carcass characteristics of goats submitted to grazing in the Caatinga

The objective of this study was to evaluate morphometric measures, carcass yields, absolute weights and yields of commercial cuts of carcass of kids with no defined breed. Eighteen castrated male goats, with average weight of 15 kg were used. The experimental period lasted 105 days. The experimental design was completely randomized; animals were allocated to three treatments: free grazing without supplementation; restricted grazing without supplementation and free grazing with supplementation. Animals were supplemented (1% of body weight) with forage cactus (Opuntia ficus - indica, Mill) and soybean meal (Glycine max). The feeding consisted of continuous grazing on caatinga. Supplemented animals had higher live slaughter weight and body score, and consequently higher morphometric measures in vivo and in carcasses. The supplementation provided carcasses with higher body weight and body score. For yields of carcass, there was no difference between treatments restricted grazing and grazing with supplementation; supplementation provided carcasses with higher yields. Supplemented animals had higher absolute weights for commercial cuts. Supplementation of grazing goats raised in the caatinga provides animals with higher body weight at slaughter, greater morphometric measures in vivo and in carcass and better body conformation. Therefore, for supplementation, the level used in this experiment is a good alternative in the creation of small ruminants during the dry period in the semi-arid region.

Desempenho de novilhas leiteiras sob manejo para crescimento compensatório recebendo suplementação com ionóforo

ABSTRACT - The objective of this trial was to compare the effect of different feeding strategies with or withoutionophore (monensin) supplementation on performance of dairy heifers. Twenty Brown-Swiss heifers averaging 200 kgof body weight and five months of age were used in a completely randomized design with a 2 x 2 factorial arrangementof treatments. Treatments were: two feeding regimes (conventional vs. compensatory growth) with (200 mg/animal/day) or without monensin supplementation. Animals in the conventional feeding regime were fed ad libitum while thosein the compensatory growth were fed as follows: P1) period of energy restriction (90 days); and P2) realimentation period(60 days). Efficiency of conversion of ingested DM and metabolizable energy on daily weight gain was lower during therealimentation period. However, nitrogen (N) balance did not differ on heifers receiving the conventional feeding regimecompared to those receiving the compensatory growth regime. Inclusion of monensin in diet of heifers reduced theexcretion of N in urine leading to greater N retention in the restriction period and lower during the realimentation phase.There was not effect of treatments, monensin or period on the development measurements and final body weight. Heifersin the compensatory growth regime had greater average daily gain at 135 and 150 days when compared to conventionalfeeding heifers.Key Words: biological efficiency, daily gain, monensin, nitrogen balance, realimentation, restriction

Modelos para ajuste da produção de gases em silagens de girassol e milho

The aim of this work was to identify among the Brody, Von Bertalanffy, Gompertz, France, Logistic, Modified logistic and Dual-pool logistic models, the one that presents the highest quality of fit for cumulative gas production curve in sunflower and corn silages. The quality of fit was evaluated by coefficient of determination, residual mean square, graphic analysis of the observed and estimated curves, graphic analysis of dispersion of the studentized residual, average percentage error, relative efficiency and number of iteractions to converge. Brody, France and Dual-pool logistic models showed the largest values of coefficient of determination in both substrates, and the difference among them was considered worthless. They also showed the smallest values of residual mean square in sunflower silages, being the difference among them considered worthless. Brody and France models presented smaller residual mean square in corn silages. All the models showed positive dispersion of the residual in both substrates after 144 hours of incubation. The Brody model showed smaller average percentage error and number of iterations in both substrates. The Dual-pool logistic and France models showed higher relative efficiency, respectively, in sunflower and corn silages. Thus, the Dual-pool logistic model showed higher quality of fit to the gas production curve in sunflower and corn silages.

Common bean residue as additive in sugarcane silage

The sugarcane has a high content of soluble carbohydrates, thereby resulting in increased production of ethanol during its fermentation. Thus, it is necessary to use an additive that reduces the losses in the nutritional value of the forage during the ensiling process.The objective was to evaluate the use of common bean residue during the sugarcane ensiling process over the silage nutritional quality and fermentation characteristics. Were used 20 silos made of PVC pipes, in which the residue of crude and previously ground common bean processing ( Phaseolus vulgaris L.) were added to newly chopped sugarcane in the proportions of 0, 50, 100 and 150 g kg -1 of natural forage matter. A randomized design was used and the regression analysis was performed according to the level of beans in silage. The losses from the ensiling process, the aerobic stability of the material, and the silage chemical composition, pH, NH 3 -N and IVDDM were analyzed. The inclusion of increasing levels of bean residue until the level of 150 g kg -1 improved the quality of silages, since there was a reduction in gaseous losses, improvement in food composition and in vitro digestibility of DM, without impairing the silages pH. The residue can be used as additive in sugarcane silage until 150 g kg -1 green material for improving silage fermentation characteristics and dry matter digestibility.

Composição da Silagem de Cana-de-Açúcar Enriquecida com Resíduo do Beneficiamento do Feijão Comum

A ensilagem da cana e uma pratica que facilita o manejo do canavial em sistemas de producao animal por melhorar a eficiencia de colheita. Apesar do crescente numero de produtores adeptos a sua adocao, ainda sao escassas as informacoes sobre a qualidade dessas silagens. Objetivou-se avaliar o efeito da adicao do residuo de feijao durante o processo de ensilagem da cana-de-acucar (Saccharum ssp.) sobre a sua composicao bromatologica. O experimento foi conduzido na UAG/UFRPE, em Garanhuns-PE. Foram utilizados 12 silos de PVC, que permaneceram em local coberto ate a abertura (45 dias). A cana foi enriquecida com niveis crescentes de residuo do feijao (Phaseolus vulgaris L.): 0; 4; 8 e 12% com base na materia natural do volumoso e tres repeticoes. A inclusao do residuo do beneficiamento do feijao durante a ensilagem da cana-de-acucar nao promoveu reducao das perdas de materia seca do material ensilado (P>0,05). Entretanto, houve melhoria significativa do material ensilado, o que pode ser observado a partir dos aumentos (P<0,05) dos niveis de materia seca, proteina bruta e carboidratos nao- fibrosos, alem das reducoes (P<0,05) dos niveis de fibra em detergente neutro e acido. Houve pequeno acrescimo no pH (P<0,05) para os niveis 8 e 12% de residuo, 3,65 e 3,69 unidades respectivamente. A inclusao do residuo de feijao durante a ensilagem da cana-de-acucar apresentou-se tecnicamente viavel. DOI:10.15528/2176-4158/rcpa.v12n2p133-137