O presente trabalho foi conduzido no Departamento de Zootecnia da UFSM com o objetivo de avaliar o valor nutritivo da casca de grão de soja moída sem tostar (peneira 2,38mm, CGSM) para ruminantes. O mesmo constou de um ensaio convencional de digestibilidade in vivo com ovinos, que durou 28 dias. Foram utilizados 23 animais machos castrados, com peso vivo médio de 32,4kg, alojados individualmente em gaiolas metabólicas e sorteados em cinco grupos (tratamentos) de cinco animais (exceto T4), num delineamento estatístico inteiramente casualizado. Os tratamentos (T) testados foram: T1 = 100% de palha de arroz triturada (PAT); T2 = 75% de PAT + 25% de CGSM; T3 = 50% de PAT + 50% de CGSM; T4 = 25% de PAT + 75% de CGSM e T5 = 100% de CGSM. A CGSM utilizada neste experimento apresentou, com base na matéria seca (MS; 89,19%), 15,67% de proteína bruta (PB), 94,74% de matéria orgânica (MO), 33,82% de fibra bruta (FB), 1,65% de extrato etéreo (EE) e 43,60% de extrativo não nitrogenado (ENN). Verificou-se, através da análise de regressão, um efeito linear altamente significativo (P < 0,01) e ascendente à medida que a CGSM substituiu a PAT nos tratamentos com relação a percentagem obtida para nutrientes digestíveis totais (NDT) e aos coeficientes de digestibilidade aparente (CDA) da MS (CDAMS), da MO (CDAMO), da PB (CDAPB), do EE (CDAEE) e do ENN (CDAENN); todavia não verificou-se efeito significativo dos tratamentos com relação ao CDA da FB (CDAFB). A CGSM apresentou, quando fornecida como alimento único (T5), 65,39% de CDAMS, 68,28% de CDAFB e 67,05% de NDT. Conclui-se que a CGSM possui um alto valor nutritivo para ruminantes.

ABSTRACT. The objective of this study was to assess the edible biomass and chemical composition of forages grown on pure form, as a grass mix, and in grass-legume consortia. The following species were tested: white oats (Avena sativa), black oats (Avena strigosa), ryegrass (Lolium multiflorum), forage peanut (Arachis pintoi), white clover (Trifolium repens), and red clover (Trifolium pratense). The experiment consisted of sixteen treatments arranged in a completely randomized design. The parameters measured were total dry matter (PMST), neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP). No significant differences in PMST were found among the consortia (p > 0.05). Only the pure cultivated white clover (p > 0.05) was comparable to the consortia in terms of biomass production. The three legumes had the lowest average NDF values (p > 0.05), based on their contributions to the total NDF content of the consortia along the cuts. The ADF content increased for all treatments during the cuts. The results indicate that in pasture, legumes increase protein content, and forage consortia increase both the pasture production and the grazing period. Their chemical composition is adequate for boosting livestock production in pastures.Keywords: Arachis pintoi, Avena sp., fiber, Lolium multiflorum, protein, Trifolium sp.Produção e composição bromatológica de gramíneas e leguminosas cultivadas de forma estreme, misturadas ou em consórcio RESUMO. Objetivou-se avaliar a produção de biomassa e a composição bromatológica ao longo do ciclo produtivo de forrageiras cultivadas de forma estreme, misturadas ou consorciadas. Foram utilizadas as seguintes espécies: aveia branca (Avena sativa), aveia preta (Avena strigosa), azevém (Lolium multiflorum), amendoim forrageiro (Arachis pintoi), trevo branco (Trifolium repens) e trevo vermelho (Trifolium pratense). As forrageiras foram cultivadas em 16 tratamentos em delineamento inteiramente casualizado, sendo analisados a produção de matéria seca total (PMST) e os teores de fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e proteína bruta (PB). Quanto à PMST, não foram constatadas diferenças (p > 0,05) entre os consórcios, sendo apenas o cultivo estreme de trevo branco comparável (p < 0,05) aos consórcios em biomassa produzida. Em relação ao FDN, as três leguminosas isoladas apresentaram os menores valores (p > 0,05) na média geral, ficando evidente a sua contribuição no teor de FDN dos consórcios ao longo dos cortes. O teor de FDA aumentou no decorrer dos cortes para todos os tratamentos. Os resultados indicam que a inclusão de leguminosas aumenta os teores proteicos, e os consórcios de forrageiras aumentam a produção de pastagem e o período de pastejo, com composição bromatológica adequada para potencializar a produção animal a pasto.

In ruminant livestock, rumen undegradable protein (RUP) derived from the diet and microbial protein synthesized in the rumen are essential for animal survival, maintenance, growth, production, and reproduction. RUP is influenced by diet composition, physical form, and ruminal metabolism. Here, we aimed to evaluate the ruminal degradability of protein feeds with different physical forms (meal versus grain) through a meta-analysis study. A database, composed of 45 treatments from 12 studies carried out in Brazil, was evaluated to compare the degradability of soybean, sunflower, canola, and flaxseed grains with the meal forms of soybean, peanut, sunflower, cottonseed, and corn gluten. The degradation parameters of dry matter did not differ significantly between meals and grains. However, the effective degradability of crude protein at a passage rate of 2% per hour was higher in meals than in grains. Overall, it was concluded that meal protein might be more degradable in the rumen of animals on an energy intake lower than the maintenance. ______________________________________________________________________________________

One factor that may interfere with rumen fermentation is the physical form of feed, because of the colonization by bacteria during processing. Here, we aimed to perform a meta-analysis and evaluate the in situ ruminal degradability of energy feeds with distinct physical forms (grain vs. meal). We created a database, comprising 39 treatments from 12 studies conducted in Brazil, and focused on parameters for the potential and effective degradability of dry matter (DM) and crude protein (CP) of energy feeds. The results showed that there was no difference (P > 0.05) in any of the degradability parameters of DM and CP between the grain and meal. However, the readily soluble fraction of DM in the grain showed a higher degradability trend (P = 0.0888). Overall, it was concluded that the processing of energy feeds does not modify the degradability parameters of DM and CP, and that further studies need to be conducted in Brazil to evaluate the in situ ruminal degradability of starch.

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The aim of this study was to evaluate the composition, voluntary intake, and digestibility of the diet of Holstein cows, as well as milk yield and milk composition as a function of different roughage sources used under experimental feeding conditions in Brazil, through meta-analysis. The database of this study consisted of 109 experiments with 424 treatments of 3,903 lactating Holstein cows. The data were obtained from studies published between January 2000 and December 2015, and were evaluated by variance analysis. Lactating dairy cow diets with a single source of roughage other than corn silage resulted in lower voluntary intake, milk yield, and differences in milk composition, compared to diets based on corn silage or the combination of two roughages, probably due to reduced nutrient digestibility. Diets based on corn silage are distinguished by feed efficiency, milk yield, and composition. Diets based on the combination of two roughage sources are similar with respect to milk yield and composition, compared to diets based on corn silage; whereas, diets with a single source of roughage (other than corn silage), even when containing a higher proportion of concentrate, led to reduced voluntary intake, milk yield, and food efficiency due to the lower utilization of the nutrients. Diets based on corn silage in general allow a higher proportion of roughage in the diet due to energy density.

Owing to the magnitude and importance of the production of citrus fruits pulp, soybeans and corn in Brazil, considerable research has focused on the main feedstuffs, co-products, and/or byproducts of these crops. The present study is aimed at comparing the ruminal degradability parameters of corn and non-starchy energy sources with high pectin content, including soybean hulls and citrus pulp, through meta-analysis. The experiments were designed to include parameters related to potential and effective degradability of the concentrates of these energy feeds. The database (DB) was composed of 62 treatments obtained from 20 papers. No difference (P>0.05) was observed in any of the ruminal degradability parameters of the dry matter (DM) or crude protein (CP), demonstrating that the total replacement of corn grain by non-starch feed is possible. The degradation rates of DM were 6.78 and 6.14%.h-1 and those of CP were 5.97 and 5.93%.h-1 , for corn and non-starch feeds, respectively. Therefore, depending on the cost, corn grain could be substituted by soybean hulls or citrus pulps, which reduce the possibility of the occurrence of metabolic disorders, such as subclinical and/or clinical acidosis, without affecting ruminal fermentation.

A meta-analysis was undertaken to examine the effects of different supplementation strategies on production of beef cattle grazing tropical pastures during the wet and dry seasons in Brazil. The database was built with 132 studies published from 1999 to 2010, which accounted for 6,275 individual animals. The supplements assessed were classified into three groups: energy supplement containing <20% crude protein (CP), protein supplement containing ≥20% CP, and urea mineral supplement. The supplementation levels ranged from 0 to 1.6% body weight (BW), and the effects of type and level of supplementation were examined during both dry and wet seasons. The meta-analysis was performed using mixed models. Cattle grazing tropical pastures during the wet season had higher average daily gain (ADG) than that in the dry season (0.81 vs. 0.56 kg/day). In response to supplementation, cattle receiving >1.0% BW of energetic supplement in the wet season had the greatest gain per hectare (GPH; 8.16 kg/ha per day) and daily stocking rate (DSR; 2045 kg BW/ha/day). In the dry season, protein supplementation at rates >0.5% BW provided higher GPH (on average 2.33 kg/ha per day). Neither level nor type of supplement altered the DSR in the dry season (on average 883 kg/ha per day). Estimated regression showed that the ADG of beef cattle increased by 0.308 kg for each 1% of supplement intake. Increased supplementation intake by beef cattle grazing tropical pastures resulted in greater ADG in the warm season, whereas offering energy supplementation at rates >1.0% BW during the wet season as well as protein supplementation at rates >0.5% BW during the dry season increased gain per area.