RESUMO -Foram determinadas as digestibilidades de matéria seca (MS), proteína bruta (PB), extrato etéreo (EE), fibra em detergente neutro (FDN), energia bruta (EB) e nutrientes digestíveis totais (NDT), utilizando-se quatro indicadores internos (FDN -fibra detergente neutro, FDA -fibra detergente ácido, lignina e CIA -cinza insolúvel em ácido). Os três primeiros indicadores foram submetidos à digestibilidade in vitro por três e seis dias, e os resultados foram comparados com dados determinados por intermédio da coleta total de fezes. Verificou-se que a digestibilidade dos nutrientes, quando estimada por intermédio dos teores de FDN, FDA e lignina incubados durante seis dias, não diferiu significativamente da digestibilidade dos nutrientes determinada pela coleta total, enquanto os indicadores incubados durante três dias e a CIA subestimaram a digestibilidade, devido à baixa recuperação destes.Palavras-chave: CIA, coleta total de fezes, FDA, FDN, lignina Evaluation of Internals Markers in Digestibility AssayABSTRACT -The digestibilities of dry matter (DM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), gross energy (GE) and total digestible nutrients (TDN) were determined by using four internal markers (acid detergent fiber -ADF and lignin and acid insoluble ash -AIA). The three first markers were submitted to in vitro disappearance for three and six days and the results were compared with data determined by total feces collection. The nutrient digestibility estimated by NDF, ADF and lignin incubated during six days did not differ from that using total feces collection, while the markers incubated during three days and AIA subestimated the digestibility of nutrients, due to their lower recovery.

RESUMO -Objetivou-se avaliar o valor nutritivo de três espécies forrageiras tropicais: capim-tanzânia (Panicum maximum Jacq.), capim-marandu (Brachiaria brizantha) e capim-tifton 85 (Cynodon spp), em duas épocas do ano (janeiromarço e abril-junho) e em três idades de rebrota (28, 35 e 42 dias), por meio da composição química, do fracionamento de proteínas e carboidratos e da digestibilidade in vitro da matéria seca (DIVMS) e da matéria orgânica (DIVMO). O capim-marandu destacou-se no período de janeiro-março, com menores conteúdos de parede celular e fração B2 dos carboidratos e maiores valores de proteína bruta, fração A + B1, DIVMS e DIVMO, em comparação aos capins tanzânia e tifton 85, independentemente da idade de corte. O aumento da concentração de parede celular em detrimento ao conteúdo celular com o avanço da maturidade das plantas foi evidente no capim-marandu no período de janeiro-março, quando foram observados maior valor da fração B2, maior conteúdo de fibra em detergente neutro (FDN) e menor concentração da fração carboidratos não-fibrosos. No período de abril-junho, a composição em parede celular não apresentou diferenças evidentes com aumento da idade, devido às condições ambientais observadas. O capim-tanzânia apresenta, de modo geral, baixos valores de parede celular e altos valores de carboidratos não-fibrosos, DIVMS e DIVMO nesse período, seguido pelos capins marandu e tifton 85, respectivamente.Palavras-chave: capim-marandu, capim-tanzânia, capim-tifton 85, conteúdo celular, parede celular, valor nutritivo Chemical composition, fractionation of carbohydrates and crude protein and in vitro digestibility on tropical forages in the different cutting ages ABSTRACT -This trial was conducted with the objective of evaluating the nutritive value of three tropical forage species: tanzania grass (Panicum maximum Jacq.), marandu grass (Brachiaria brizantha) and Tifton 85 bermudagrass (Cynodon spp) in two different periods of the year (January-March and April-June) and in three cutting ages (28, 35 and 42 days), based on the chemical composition, protein and carbohydrate fractions, and in vitro digestibility of dry matter (DMD) and organic matter (OMD). Marandu grass, in the period January-March, had the lowest cellular wall contents and B2 fraction of carbohydrates, and higher values of crude protein, A + B1 fraction, DMD and OMD in comparison to tanzania grass and Tifton 85 bermudagrass, regardless of the cutting age. The increase of concentration of the cell wall in detriment to the cell content as plant maturity advanced was evident in marandu grass during January-March when higher values of B2 fraction, higher content of neutral detergent fiber and lower concentrations of non fibrous carbohydrate fractions were observed. In April-June period, the cellular wall contents did not show evident differences as age increased due to environmental conditions. The tanzania grass presents, in general, lower values of the cell wall and higher values of non fibrous carbohydrate, DMD and OMD during this period, f...

This study aimed to examine the effects of feeding corn silage inoculated without or with either Lactobacillus buchneri (LB) alone or a combination of LB and Lactobacillus plantarum (LBLP) on the apparent digestibility, ruminal fermentation, microbial protein synthesis, and growth performance of lambs. Thirty Santa Inês×Dorper crossbred intact males lambs weighing 20.4±3.8 kg were blocked by weight into 10 groups. Lambs in each group were randomly assigned to 1 of the following 3 dietary treatments: untreated (Control), LB, and LBLP silage. Lambs were fed experimental diets for 61 d. The apparent digestibility was indirectly estimated from indigestible NDF measured on d 57 to 59. Spot urine samples were collected from all animals on d 59 to estimate microbial protein synthesis. Lambs were slaughtered for carcass evaluation on d 61 when they weighed 32.4±5.2 kg. Six additional ruminally cannulated Santa Inês×Dorper crossbred wethers weighing 40.5±1.8 kg were used to examine dietary effects on ruminal fermentation. Average daily gain was increased when lambs were fed LBLP silage (P<0.05) but not LB silage. The LBLP silage had the highest (P<0.05) lactic acid concentration and both inoculated silages had greater acetic acid concentrations than the Control silage (P<0.05). Inoculation of corn silage increased intakes of DM, OM, CP, NDF, total carbohydrate (CHO), and GE by the lambs but decreased digestibility of DM, OM, CP, total and nonstructural carbohydrates, and concentration of GE and ME. (P<0.05). Nevertheless, lambs fed inoculated silages had greater microbial N supply than those on the Control treatment (P<0.05). The acetate to propionate ratio was lower in ruminal fluid of wethers in LBLP treatment than LB and Control treatment (P<0.05) and ruminal pH tended to be greater in LB lambs than in LBLP and Control wethers (P<0.10). Finally, the inoculation with both bacteria combined enhanced the silage fermentation. The intakes of DM, OM, CP, NDF, and GE were improved in the lambs fed corn silage inoculated with L. buchneri alone or combined with L. plantarum. The microbial N supply was enhanced in the lambs fed corn silage inoculated with L. buchneri. The inoculation of L. buchneri combined with L. plantarum reduced the acetate to propionate ratio in ruminal fluid and improved the ADG of lambs.

Resumo -O objetivo deste trabalho foi quantificar a taxa de emissão de metano (CH 4 ) pela técnica do gás traçador, hexafluoreto de enxofre (SF 6 ), em bovinos leiteiros a pasto em condições tropicais brasileiras. As medições foram realizadas na estação das chuvas, com adequada oferta de forragem, em animais da raça Holandesa e Mestiça Leiteira Brasileira em pastagem de capim-tobiatã (Panicum maximum Jacq. cv. Tobiatã) adubada, com vacas em lactação, vacas secas e novilhas, e em pastagem de capim-braquiária (Brachiaria decumbens Stapf.) não adubada com novilhas. As concentrações de CH 4 e SF 6 foram determinadas por cromatografia gasosa. A emissão de CH 4 pelas vacas em lactação foi de 13,8 a 16,8 g/hora, pelas vacas secas de 11,6 a 12,3 g/hora, pelas novilhas em pastagem adubada de 9,5 g/hora, e pelas novilhas em pastagem sem adubo de 7,6 a 8,3 g/hora ou 66 a 72 kg/animal/ano. A emissão de CH 4 por matéria seca digestiva ingerida foi de 42 a 69 g/kg em vacas em lactação, de 46 a 56 g/kg em vacas secas, 45 a 58 g/kg em novilhas ingerindo pasto adubado e 58 a 62 g/kg em novilhas em pastagem sem adubo. A emissão de CH 4 por bovinos leiteiros ingerindo gramíneas tropicais é superior à emissão por bovinos ingerindo gramíneas de clima temperado.Termos para indexação: traçador interno, hexafluoreto de enxofre, metano ruminal, gás de efeito estufa. Dairy cattle enteric methane measured in Brazilian tropical conditionsAbstract -The objective of this work was to quantify methane (CH 4 ) emission using the sulfur hexafluoride (SF 6 ) tracer technique, by dairy cattle on pasture in Brazilian tropical field conditions. Measurements were performed in the rainy season, with Holstein and Holstein x Zebu crossbred, from lactating and dry cows and heifers grazing fertilized Tobiatã grass, and heifers grazing unfertilized Brachiaria grass. Methane and SF 6 concentrations were determined by gas chromatograph. Methane emissions by lactating cows varied from 13.8 to 16.8 g/hour, by dry cows from 11.6 to 12.3 g/hour, by heifers grazing fertilized grass was 9.5 g/hour and by heifers grazing unfertilized grass varied from 7.6 to 8.3 g/hour or 66 to 72 kg/head/year. Methane emission per digestive dry matter intake (DMDI) varied from 42 to 69 g/kg DMDI for lactating cows, 46 to 56 g/kg for dry cows, 45 to 58 g/kg for heifers grazing fertilized grass and 58 to 62 g/kg for heifers in unfertilized grass pasture. The CH 4 emission measured on dairy cattle feeding tropical grasses was higher than that observed for temperate climate conditions. Index terms: internal tracer, sulfur hexafluoride, ruminal methane, greenhouse gas.(1) Embrapa Pecuária Sudeste, Caixa Postal 339, CEP 13560-970 São Carlos, SP. E-mail: odo@cppse.embrapa.br (2) Embrapa Meio Ambiente, Caixa Postal 69, CEP 13820-000 Jaguariúna, SP. E-mail: rosa@cnpma.embrapa.br, magda@cnpma.embrapa.br (3) Universidade Estadual Paulista, Fac. de Ciências Agrárias e Veterinárias, Via de acesso Professor Paulo Donato Castelanne, km 5, s/n o , CEP 14884-900 Jaboticabal, SP. E-mail: pedreira@f...

The present study was conducted to evaluate the effect of lipids with different fatty acid profiles on the intake, performance, and enteric CH4 emission of Nellore steers. A total of 45 Nellore animals with an average initial BW of 419 ± 11 kg (at 15 ± 2 mo) were distributed in a completely randomized design consisting of 5 treatments and 9 replicates. The roughage feed was maize silage (600 g/kg on a DM basis) plus concentrate (400 g/kg on a DM basis). The dietary treatments were as follows: without additional fat (WF), palm oil (PO), linseed oil (LO), protected fat (PF; Lactoplus), and whole soybeans (WS). The lipid source significantly affected (P < 0.05) nutrient intake. The greatest intakes of DM, OM, and CP were observed in the animals that were fed the WF or PF diets, and the lowest intakes were observed in the animals that were fed the PO diet. Intake of NDF decreased (P < 0.05) with the addition of PO. Enteric methane emission (g/kg DMI) was reduced by an average of 30% when the animals were fed diets containing WS, LO, and PO (P < 0.05), and these diets caused a larger reduction in the energy loss in the form of methane compared to those without added fat and with added PF (3.3 vs. 4.7%). The different fatty acid profiles did not affect the backfat thickness or the loin eye area of the animals (P > 0.05). However, animals fed PO displayed lower daily weight gain (0.36 kg/d), feed efficiency (0.08 kg ADG/kg DM), HCW (245 kg), and hot yield percentage (52.6%) compared to animals that were fed the other diets. Therefore, PO compared to the other lipid sources used in this study reduces intake, performance, feed efficiency, and carcass yield. Therefore, PO is not suggested for feedlot-finished animals.