Levels Of Neutral Detergent Fiber Research Articles

Methods of lab silos sealing and fermentation characteristics and aerobic stability of sugarcane silage treated with microbial additive

The present experimental assay evaluated the effect of lab silo sealing methods on the ensilage of the sugarcane, with or without microbial additives (Lactobacillus plantarum and Propionibacterium acidipropionici). Twenty-liter plastic buckets were used as experimental silos, which were sealed with either a polyethylene sheet (silo cover with a mesh size of 200 µm) or an appropriate plastic lid equipped with Bunsen valve. Silos were stored for 30, 60, or 90 days. Fermentative losses, chemical composition, organic acids, ethanol and aerobic stability were evaluated. The sealing method employed did not influence most of evaluated variables, showing a small decrease of effluent production in silos covered with polyethylene sheet. The microbial additive did not avoid dry matter (DM) fermentative losses in sugarcane silages (216 g kg-1), nor affected aerobic stability (44.6 hours). The levels of neutral and acid detergent fiber of fresh sugarcane increased after ensiling due to DM losses as gases and effluent. The ethanol content of silages was not influenced by treatments (mean 146 g kg-1 of DM). The sealing methods of experimental silos were not affected by the evaluated variables; polyethylene sheet and plastic lid show the same performance on the fermentative model and both methods represent well the conditions of large scale farm silos.

Bromatological evaluation of eleven corn cultivars harvested at two cutting heights

The objective of this study was to evaluate the chemical composition and dry matter in vitro digestibility of stem, leaf, straw, cob and kernel fractions of eleven corn (Zea mays) cultivars, harvested at two cutting heights. The experiment was designed as randomized blocks, with three replicates, in a 2 × 11 factorial arrangement (eleven cultivars and two cutting heights). The corn cultivars evaluated were D 766, D 657, D 1000, P 3021, P 3041, C 805, C 333, AG 5011, FOR 01, CO 9621 and BR 205, harvested at a low cutting height (5 cm above ground) and a high cutting height (5 cm below the first ear insertion). Cutting height influenced the dry matter content of the stem fraction, which was lower (23.95%) in plants harvested at the low, than in plants harvested at the high cutting height (26.28%). The kernel fraction had the highest dry matter in vitro digestibility (85.13%), while cultivars did not differ between each other. Cob and straw were the fractions with the highest level of neutral detergent fiber (80.74 and 79.77%, respectively) and the lowest level of crude protein (3.84% and 3.69%, respectively). The leaf fraction had the highest crude protein content, both for plants of low and high cuttings (15.55% and 16.20%, respectively). The increase in the plant cutting height enhanced the dry matter content and dry matter in vitro digestibility of stem fraction, but did not affect the DM content of the leaf fraction.

P099 L’amélioration de la qualité nutritionnelle des laits profite-telle à la santé et à la fertilité des vaches ?

The objective of this study was to investigate whether higher lucerne (Medicago sativa; alfalfa) silage inclusion rate and longer lucerne chop length improves rumen function through increased provision of physically effective fiber, when included in a maize and lucerne silage-based total mixed ration. Diets were formulated to contain a 50:50 forage:concentrate ratio [dry matter (DM) basis] and be isonitrogenous and contain equal levels of neutral detergent fiber (320 g/kg). The forage portion of the offered diets was composed of maize and lucerne silage DM in proportions (wt/wt) of either 25:75 (high lucerne; HL) or 75:25 (low lucerne; LL). Second-cut lucerne was harvested and conserved as silage at either a long (L) or a short (S) chop length (geometric mean particle lengths of 9.0 and 14.3 mm, respectively). These variables were combined in a 2 × 2 factorial arrangement to give 4 treatments (HLL, HLS, LLL, LLS), which were fed in a 4 × 4 Latin square design study to 4 rumen-cannulated, multiparous, Holstein dairy cows in mid lactation. Effects on DM intake, chewing behavior, rumen volatile fatty acid concentration, rumen pH, rumen and fecal particle size, milk production, and milk fatty acid profile were measured. Longer chop length increased rumination times per kilogram of DM intake (+2.8 min/kg) relative to the S chop length, with HLL diets resulting in the most rumination chews. Rumen concentrations of total volatile fatty acids, acetate, and n-valerate were higher for the HLS diet than the other 3 diets, whereas rumen propionate concentration was lowest for the HLL diet. Physically effective fiber (particles >4 mm) percentage in the rumen mat was increased when L chop length was fed regardless of lucerne inclusion rate. No effect of treatment was observed for milk yield, although milk protein concentration was increased by L for the LL diet (+1.6 g/kg) and decreased by L for the HLL diet (−1.4 g/kg). Milk fat concentrations of total cis-18:1 (+3.7 g/100 g of fatty acids) and 18:3 n-3 (+0.2 g/100 g of fatty acids) were greater with HL. In conclusion, longer lucerne silage chop length increased time spent ruminating per kilogram of DM intake, but had no effect on rumen pH in the present study. Increasing dietary lucerne inclusion rate had no effects on rumination activity or rumen pH, but decreased the ratio of n-6:n-3 polyunsaturated fatty acid concentrations in milk fat.

Effect of lactic acid bacteria inoculant and beet pulp addition on fermentation characteristics and in vitro ruminal digestion of vegetable residue silage

The objective of this study was to determine the effect of beet pulp (BP) and lactic acid bacteria (LAB) on silage fermentation quality and in vitro ruminal dry matter (DM) digestion of vegetable residues, including white cabbage, Chinese cabbage, red cabbage, and lettuce. Silage was prepared using a small-scale fermentation system, and treatments were designed as control silage without additive or with BP (30% fresh matter basis), LAB inoculant Chikuso-1 (Lactobacillus plantarum, 5mg/kg, fresh matter basis), and BP+LAB. In vitro incubation was performed using rumen fluid mixed with McDougall's artificial saliva (at a ratio of 1:4, vol/vol) at 39°C for 6h to determine the ruminal fermentability of the vegetable residue silages. These vegetable residues contained high levels of crude protein (20.6–22.8% of DM) and moderate levels of neutral detergent fiber (22.7–33.6% of DM). In all silages, the pH sharply decreased and lactic acid increased, and the growth of bacilli, coliform bacteria, molds, and yeasts was inhibited by the low pH at the early stage of ensiling. The silage treated with BP or LAB had a lower pH and a higher lactic acid content than the control silage. After 6h of incubation, all silages had relatively high DM digestibility (38.6–44.9%); in particular, the LAB-inoculated silage had the highest DM digestibility and the lowest methane production. The vegetable residues had high nutritional content and high in vitro DM digestibility. Also, both the addition of a LAB inoculant and moisture adjustment with BP improved the fermentation quality of the vegetable residue silages. In addition, LAB increased DM digestibility and decreased ruminal methane production.

EFFECTS OF LEVELS OF INSOLUBLE AND SOLUBLE FIBRE IN DIETS FOR GROWING RABBITS ON FAECAL DIGESTIBILITY, NITROGEN RECYCLING AND IN VITRO FERMENTATION

The effect of neutral detergent fibre (NDF) and neutral detergent soluble fibre (NDSF) on in vivo faecal digestibility and caecal fermentation pattern was studied in growing rabbits, in four diets formulated according to two levels of NDF, 370 (LI) and 450 (HI) g/kg, and two levels of NDSF, 150 (LS) and 180 (HS) g/kg in substitution of starch, in a 2x2 factorial structure. Twenty four New Zealand White rabbits weaned at 28 d (630 ± 80.2 g weight) were allocated to digestibility cages from 42 to 49 d of age to determine apparent faecal digestibility of each diet (n=6). Urine was collected for determination of purine derivatives (PD). Once the digestibility trial finished, rabbits were fitted with PVC neck collars for 24 h total caecotrophe collection. After one day of recovery, animals were slaughtered and caecal contents were used as inocula for 18 h in vitro gas production and caecal degradation (ivDMcD) study, using an HCl-pepsin and pancreatin pre-digested substrate. Diet digestibility was also determined by the in vitro three-step enzymatic procedure. There were no effects of the NDF x NDSF interaction for any digestibility parameter (P>0.10). Both dry matter and organic matter digestibility (DMD and OMD) decreased from 0.518 to 0.442 and from 0.526 to 0.447, respectively, with the inclusion of NDF (P<0.001), but were unaffected by the NDSF level (P>0.10). In contrast, NDF digestibility (NDFD) and ivDMcD did not respond to NDF (P>0.10) but increased from 0.156 to 0.200 and 0.141 to 0.210 with a ratio of NDSF (P<0.01). Weight of caecal contents increased with both NDF (P<0.001) and NDSF (P<0.01). However, total production of caecotrophes increased from 20.1 to 25.5 g DM/d with NDF (P<0.05), but was not affected by NDSF. The crude protein (CP) proportion in caecotrophes decreased with NDF (P<0.001) and increased with NDSF (P<0.01), and total CP recycled as caecotrophes tended (P=0.093) to be higher in HS diets, being unaffected by the dietary level of NDF. Diets rich in NDSF rendered higher gas volumes (P<0.001) than those with LS from 2 to 18 h incubation, whereas inclusion of high proportions of NDF reduced gas volume (P<0.01). Results indicate that NDF reduces faecal digestibility, whereas NDSF promotes better conditions for caecal fermentation.

Qualidade forrageira do capim-capivara em áreas de várzea, na região central do Rio Grande do Sul, Brasil

Hymenachne amplexicaulis (capim-capivara) é uma gramínea semi-aquática, estolonífera, que pode estabelecer densas formações em ambientes que se inundam e nas margens de rios em regiões tropicais e subtropicais. Com o objetivo de determinar a qualidade bromatológica e a digestibilidade de H. amplexicaulis presente em áreas de várzea, foram realizadas coletas nos municípios de Formigueiro, Santa Maria e São Vicente do Sul, municípios da Depressão Central do Rio Grande do Sul, Brasil. Foram determinados os teores de matéria seca (MS), proteína bruta (PB), fibra em detergente ácido (FDA), fibra em detergente neutro (FDN), matéria orgânica (MO), matéria mineral (MM) e digestibilidade in vitro da matéria orgânica (DIVMO), que apresentaram valores médios 23,24%, 7,42 (%MS), 67,01 (%AMS), 35,75 (%MS), 91,44 (%MS), 8,55 (%MS) e 55,41% (DIVMO), respectivamente. H. amplexicaulis, coletado em áreas de várzea na região central do RS, apresenta qualidade bromatológica para uso na alimentação animal, apesar dos reduzidos valores de proteína bruta e digestibilidade encontrados no estádio avaliado.

Comportamento alimentar de cabras alimentadas com diferentes teores de fibra em detergente neutro

Avaliou-se o comportamento alimentar de cabras alimentadas com dietas que continham diferentes teores de fibra em detergente neutro (FDN) - 49, 54, 59, 64 e 69% -, em função de diferentes teores de inclusão de resíduo úmido de cervejaria (RUC), em substituição ao concentrado da dieta - 0, 25, 50, 75 e 100%. Foram utilizadas cinco cabras mestiças Boer x Saanen e cinco cabras Saanen distribuídas em dois quadrados latinos 5x5. O volumoso utilizado foi feno de tifton, com relação volumoso: concentrado de 40:60. As observações foram feitas em períodos de 20 minutos até o tempo total de 24 horas. Os animais dos diferentes genótipos não apresentaram diferenças no comportamento alimentar. Os tempos gastos com alimentação e com ociosidade não diferiram quanto aos teores de FDN na dieta, no entanto resposta linear crescente foi observada para os tempos despendidos com ruminação e com a mastigação total com o aumento dos teores de FDN e RUC na dieta. As dietas com os teores de 49 e 64% apresentaram menor tempo de ruminação quando comparadas com a dieta com teor de 69% de FDN, com resultados respectivos de 218, 268 e 366 minutos de ruminação. Isso contribuiu para diminuir a eficiência (min/kg MS e FDN) de alimentação, ruminação e mastigação. Conclui-se que o resíduo úmido de cervejaria pode ser usado como fonte de fibra efetiva na dieta de cabras.

Prediction of rumen microbial N supply in bovines from dietary values of partitioning factor (PF), in vitro rate of gas production ( k), neutral detergent fibre and crude protein: A brief systematic review of studies completed in Bengaluru (India)

Experiments which used crossbred cows and heifers, from peer review publications originating from the Karnataka Veterinary, Animal and Fisheries Sciences University (Bidar) and Veterinary College (Bengaluru) in India were used to determine if ruminal microbial N (MN) supply could be predicted based upon the partitioning factor (PF, mg in vitro true digested organic matter: ml gas) of the diets fed to the cattle, their rate of gas production in vitro ( k, /h,) as well as the neutral detergent fibre (NDFom) and crude protein levels of the diets. The MN supply to the duodenum was quantified based on allantoin excretion in urine. The five published experiments included 15 treatment groups. Multiple correlation analysis showed that the quadratic component of diet NDFom (P=0.02) and the linear (P<0.01) and quadratic (P<0.01) components of diet k ( i.e., r 2 = 0.87) predicted supply of microbial N (MN) to the duodenum according to the equation: MN (g/kg ADOM) = −25.7 + (1402* k) − (10177.4* k 2) − (0.0000163*NDFom 2) [SEP = 0.81], where k is in unit/h and NDFom is g/kg DM. Residuals of predicted versus actual MN values showed equal distribution. Changes in predicted values of MN were judged to be consistent with our understanding of their function in the rumen, as well as quantitatively consistent with published values determined in vivo. Overall, according to the prediction equation, supply of MN increases with increasing low levels of NDFom in the diet, but is maximized at all dietary NDFom levels with a dietary in vitro rate of gas production of 0.065–0.070/h. Results support utilizing in vitro rate of gas production in diet formulation, but not PF, although research with higher production ruminants is warranted.

Produção e composição bromatológica de vinte e cinco genótipos de sorgo (Sorghum bicolor (L.) Moench)

Chemical composition and dry matter (DM) productivity of 25 genotypes of sorghum were obtained. The experiment was carried out in a randomized block design with 25 treatments and three replications each. The data were submitted to analysis of variance and the means grouped by Scott-Knot Test (5%). The level of DM productivity varied from 6.82 to 14.17ton/hectare, and the higher level was obtained by VOLUMAX genotype (16.09 ton/hectare). The levels of crude protein varied from 5.24 to 7.79%. No differences were detected between the genotypes to neutral detergent fiber levels, which varied from 59.03 to 73.04%. Considering the level of acid detergent fiber, the variation interval was 26.78 to 40.92%. The better genotypes for silage production were ATF54*9929036, CMSXS212*9929048, CMSXS217*9929012, and VOLUMAX.

Effects of prepartum roughage neutral detergent fiber levels on periparturient dry matter intake, metabolism, and lactation in heat-stressed dairy cows

Heat stress of lactating cattle results in dramatic reductions in dry matter intake (DMI). As a result, energy input cannot satisfy energy needs and thus accelerates body fat mobilization. Decreasing the level of roughage neutral detergent fiber (NDF) in prepartum diets, and thereby increasing the amount of nonfiber carbohydrates, may provide an adequate supply of energy and glucose precursors to maintain and minimize the decrease in DMI while reducing mobilization of adipose tissue. The effects of 3-wk prepartum diets containing different amounts of roughage NDF on DMI, blood metabolites, and lactation performance of dairy cows were investigated under summer conditions in Thailand. Thirty cross-bred cows (87.5% Holstein × 12.5% Sahiwal) were dried off 60 d before their expected calving date and were assigned immediately to a nonlactating cow diet containing the net energy for lactation recommended by the National Research Council (2001) model. The treatment diets contained 17.4, 19.2, and 21.0% DM as roughage NDF from bana grass (Pennisetum purpureum × Pennisetum glaucum) silage. Levels of concentrate NDF were 39.8, 40.2, and 38.6% of dietary NDF, so the levels of dietary NDF were 28.9, 32.1, and 34.2% of DM. After parturition, all cows received a lactating cow diet containing 12.7% roughage NDF and 23% dietary NDF. During the entire experiment, the minimum and maximum temperature-humidity index averaged 77.7 and 86.8, respectively, indicating conditions appropriate for the induction of extreme heat stress. As parturition approached, DMI decreased steadily, resulting in a 12.9, 25, and 32.8% decrease in DMI from d −21 until calving for nonlactating cows fed prepartum diets containing 17.4, 19.2, and 21% roughage NDF, respectively. During the 3-wk prepartum period, intakes of DM and net energy for lactation and concentrations of plasma glucose and serum insulin were higher for cows fed diets containing less roughage NDF. In cows fed the 3-wk prepartum diets containing less roughage NDF, calf birth weights, milk yield, and 4% fat-corrected milk were higher, whereas periparturient concentrations of serum nonesterified fatty acids and plasma β-hydroxybutyrate were lower. There was a carryover effect of the prepartum diet on serum nonesterified fatty acids and plasma β-hydroxybutyrate during the first 7 d in milk, and therefore on milk production. These results suggest that feeding diets containing decreased amounts of roughage NDF during the 3-wk prepartum period may minimize the decrease in DMI and lipid mobilization as parturition approaches. This strategy may thus minimize the effect of hormonal factors and heat stress on periparturient cows.

Chemical treatment of post-harvest Marandu grass seed residues with different moisture contents

The objective of this was to evaluate the effect of chemical treatments with urea (3 or 5% DM) and anhydrous ammonia (3% DM) applied to the post-harvest hay residues of Brachiaria brizantha cv. Marandu that contained different moisture contents (15, 25 or 30%). A randomized block design was used with eight treatments and four replications (defined as the bale layers within the hay stacks). The hay treated with 3% anhydrous ammonia and 15% moisture content reduced the levels of neutral detergent fiber (NDF) from 84.3 to 79.1% and increased the in vitro digestibility of the dry matter (DM) from 37.3 to 55.5% compared to the control group. The variation in the moisture content did not significantly alter the action of ammonia, with mean values of 77.6% NDF and 57.3% in vitro digestibility of DM. The hay with 5% urea reduces the NDF content from 84.3 to 79.6% compared to the untreated hay, so the hay moisture content has to be increased to 30% to achieve a greater effect on the DM digestibility, which subsequently increases by 12 percentage units.

Comportamento ingestivo de cordeiros e digestibilidade dos nutrientes de dietas contendo alta proporção de concentrado e diferentes fontes de fibra em detergente neutro

Dois experimentos foram realizados para avaliar os efeitos da substituição da fibra em detergente neutro (FDN) do bagaço de cana-de-açúcar in natura pela FDN da casca de soja em dietas com alta proporção de concentrado sobre o comportamento ingestivo de cordeiros e a digestibilidade dos nutrientes. No primeiro experimento, 60 cordeiros com 16,4 ± 0,3 kg de peso corporal e idade inicial de 67 ± 2 dias foram distribuídos em delineamento de blocos completos casualizados, em esquema fatorial 2 × 2 + 1, composto de duas fontes de FDN (bagaço de cana in natura ou casca de soja), dois teores de FDN (14 ou 18%) e uma dieta controle contendo 100% de concentrado. No segundo experimento, cinco cordeiros foram distribuídos em quadrado latino 5 × 5 e submetidos às mesmas dietas do experimento 1. As dietas contendo as fontes de fibra promoveram maior consumo de matéria seca, matéria orgânica e FDN e maior tempo de ingestão, ruminação e mastigação (minutos/dia) em comparação à dieta contendo 100% de concentrado. As dietas contendo o bagaço de canade-açúcar in natura proporcionaram maior atividade de ruminação que aquelas com casca de soja. Entretanto, a utilização da casca de soja proporcionou menor atividade de mastigação e maior digestibilidade dos nutrientes em relação ao bagaço de cana-de-açúcar in natura. A casca de soja pode ser utilizada como única fonte adicional de FDN em dietas contendo alto teor de concentrado para cordeiros.

Efeito dos níveis de fibra em detergente neutro oriunda da forragem sobre a eficiência microbiana e os parâmetros digestivos em cabras leiteiras

Objetivou-se com este trabalho avaliar o efeito de dietas com diferentes concentrações de fibra em detergente neutro oriunda da forragem (FDNf) sobre os parâmetros ruminais (pH e amônia) em cabras leiteiras. Foram utilizados cinco cabras não-lactantes fistuladas no rúmen arranjadas em delineamento quadrado latino 5 × 5, utilizando-se os níveis de FDNf (19, 27, 35, 42 e 48%) como variável independente. O aumento dos níveis de FDNf das rações reduziu linearmente os coeficientes de digestibilidade aparente da MS, MO, EE e CNF e afetou de forma quadrática o coeficiente de digestibilidade da FDN. Os coeficientes de digestibilidade ruminal da MS, MO e FDN aumentaram linearmente com a variação dos níveis de FDNf. De forma contrária, observou-se redução no coeficiente de digestibilidade intestinal da MS, MO, PB e FDN. O aumento no teor de FDNf e os tempos de coleta influenciaram o pH ruminal, contudo a amônia ruminal foi afetada apenas pelos tempos de coleta. A eficiência de síntese de proteína microbiana, quando expressa em g/kg NDT, foi influenciada pela elevação dos níveis de FDNf, e foi melhor no nível de 29,57% de FDNf.

Alternative fibre sources for steers and calves fed high-grain feedlot diets

An experiment was conducted to evaluate the effect of fibre source (FS) in high-grain feedlot diets on liveweight gain (LWG) of steers and calves and carcass traits of steers at slaughter. Eighteen steers (330 ± 27.3 kg) and 18 calves (153 ± 11.9 kg) were randomly allotted within animal category to one of three high-grain diets varying in the FS, including either grass hay (H, 66% neutral detergent fibre (NDF)), rice hulls (RH, 85% NDF) or wood chips (W, 90% NDF), and a total mixed ration formulated for equal levels of digestible DM, crude protein and NDF, within category. Animals were individually fed (3 kg DM/100 kg LW, distributed in four meals) during 56 days. The LW increased linearly with time in all treatments (P &lt; 0.01). FS did not affect calves’ LWG (P &gt; 0.05), but it resulted in differences in steers LWG (H: 1.77b; RH: 1.51c; W: 2.02a kg/day, P &lt; 0.05). However, no differences were observed in hot carcass weight (P &gt; 0.05), which resulted in higher carcass yield (P &lt; 0.05) for steers fed RH (55.0%) compared with H (53.5%) and W (53.3%). There was a significant interaction (P &lt; 0.05) for feed : gain ratio, with an improvement of this value observed only for steers fed the W diet. Although varying the FS affected rumination of calves and steers (P &lt; 0.01) and the time spent eating of steers (P &lt; 0.05), it did not represent any constraint for animal production. This study suggests by-products high in fibre content, such as RH and W, could be used in substitution to H in high-grain feedlot diets when fed at equal NDF concentration in the ration, both for calves and steers. Because calves are sometimes grown on a high-concentrate diet during winter before spring grazing, further research is needed to quantify potential residual effects on LWG after they return to pasture.

Forage management effects on protein and fiber fractions, protein degradability, and dry matter yield of red clover conserved as silage

Due to the action of o-quinones formed via polyphenol oxidase, conserved red clover ( Trifolium pratense L.) contains abundant rumen undegradable protein (RUP), but inadequate rumen degradable protein (RDP) for dairy cattle. This study examined how forage management influences RDP, RUP, crude protein (CP) and fiber fractions in red clover silage and dry matter (DM) yields during the first full production year. In 2003 and 2006, red clover was cut early on 7 June or late on 14 June with two ∼40 d regrowth cuts. For comparison, alfalfa ( Medicago sativa L.) was cut early on 26 May with three ∼32 d regrowth cuts or late using the same schedule as early cut red clover. After ensiling at 370 g/kg DM, CP and fiber were fractionated according to the Cornell Net Carbohydrate and Protein System (CNCPS). RDP and RUP were calculated from CNCPS fractions or estimated by a more convenient Streptomyces griseus protease procedure, which gave highly related ( R 2 ≥ 0.95) estimates of CP degradability. Early cutting of red clover favorably decreased RUP, neutral detergent fiber (NDF), and acid detergent fiber (ADF) and increased RDP and CP in the first two harvests. Regression analyses indicated desirable levels of RDP (>150 g/kg DM) and NDF (∼400 g/kg DM) could be obtained by harvesting red clover at a mean stage weight maturity of 2.0 at first cut, 3.0 at second cut, and 3.5–4.0 at third cut. Averaged across harvest schedules, red clover had lower RDP, CP and ADF, higher RUP, and similar NDF compared to alfalfa. Total DM yields of red clover and alfalfa were not influenced by harvest schedule. Time of establishment had little effect on silage quality, but it did influence total DM yields; April vs. August seeding depressed red clover yields (12.3 t/ha vs. 13.1 t/ha) but enhanced alfalfa yields (12.5 t/ha vs. 11.9 t/ha) during the first full production year. Overall, these results suggest protein utilization and performance of dairy cattle could be moderately improved without sacrificing DM yield by taking a very early first cutting of red clover followed by regrowth cuttings made at progressively later maturities.

Perfilhamento, acúmulo de forragem e composição bromatológica do capim-braquiária adubado com nitrogênio

Avaliaram-se a demografia de perfilhos, a composição morfológica do pasto, o índice de área foliar (IAF), a taxa de acúmulo de massa seca de forragem (TAcMS) e os teores de proteína bruta, fibra em detergente neutro e lignina e os coeficientes de digestibilidade in vitro da massa seca de Brachiaria decumbens cv. Basilisk submetido a adubação nitrogenada (75, 150, 225 e 300 kg/ha.ano de N), em lotação contínua com taxa de lotação variável em dois anos agrícolas consecutivos. O delineamento foi em blocos casualizados, com duas repetições. No primeiro ano, a demografia de perfilhos vivos não foi alterada pelos meses de avaliação, mas, no segundo ano, foi maior nos meses de março e abril. A adubação nitrogenada promoveu resposta linear positiva na demografia de perfilhos vivos, no índice de área foliar e na taxa de acúmulo de massa seca. Maiores proporções de lâminas foliares foram constatadas em março do primeiro ano e em dezembro e janeiro do segundo ano, entretanto, as proporções de colmos no pasto não diferiram entre os meses de avaliação nos dois anos. Também foram observadas respostas lineares positivas dos teores de PB às doses de nitrogênio aplicadas em todos os meses nos dois anos. Os teores de FDN e lignina do capim-braquiária são influenciados pelos meses de avaliação e variam entre anos.

Chemical composition, biological effects of tannin and in vitro nutritive value of selected browse species grown in the West Australian Mediterranean environment

Acacia saligna, Chamaecytisus palmensis, Atriplex amnicola and Atriplex nummularia are major cultivated browse forage species in Western Australia (WA). Rhagodia eremaea, a browse species indigenous to the southern rangelands of WA is currently being investigated as a potential browse species for cultivation as a feed resource for ruminants. The chemical composition and nutritive value of these browse species, when grown in the Mediterranean environment of WA were examined and compared with that of A. sativa hay, which is commonly used in ruminant feeding systems in Australia. All were analyzed for nutrient composition, total phenolics (TP), and total tannin (TT) and mineral composition. In vitro gas production was measured until 24 h, with and without the addition of polyethylene glycol (PEG). The organic matter digestibility (OMD), and metabolizable energy content (ME) were estimated. Browses all contained higher levels of CP (96.7–216.7 g/kg DM vs 52.5 g/kg DM) but lower levels of neutral detergent fiber (233.0–487.8 g/kg DM vs 611.6 g/kg DM) than A. sativa. The browses were rich in most minerals including Ca, Mg and Zn, which were deficient in A. sativa. The content of lignin(sa) was highest in A. saligna (123.2 g/kg DM). Although, C. palmensis had the highest level of TP (44.3 g/kg DM), A. saligna had the highest level of TT (28.9 g/kg DM). While phenolics in A. sativa and halophytes species ( A. amnicola, A. nummularia, R. eremaea) were very low, the latter was extremely high in ash (156.9–178.8 g/kg DM). Significant improvement of in vitro gas parameters with the addition of PEG observed only in A. saligna. The ash, lignin(sa), TP and TT contents in the leguminous species ( A. saligna, C. palmensis) were negatively correlated with in vitro nutritive characteristics ( r > −0.78). C. palmensis was higher in OMD (667.5 g/kg DM) and ME (10.0 MJ/kg DM) compared to the other browse species. The nutritive value (OMD, ME) of A. saligna was limited due to higher TP and lignin(sa) contents while that of the halophytes was limited by higher ash and, presumably, high soluble N contents. All of the browse species were rich in CP and minerals and therefore useful supplements for low CP forage diets. With the exception of C. palmensis, the other browses were poor in OMD and ME and therefore would not be suitable as a sole diet for sheep.

Dietary level of fibre and age at weaning affect the proliferation of Clostridium perfringens in the caecum, the incidence of Epizootic Rabbit Enteropathy and the performance of fattening rabbits

An experiment was conducted to investigate the effects of dietary fibre content and weaning age on Clostridium perfringens proliferation in the caecum and fattening mortality in growing rabbits farmed in a facility having Epizootic Rabbit Enteropathy. The experiment consisted in a 2 × 2 factorial arrangement with two weaning ages (28 days vs. 42 days) and two levels of dietary neutral detergent fibre assayed with a heat stable amylase and expressed exclusive of residual ash (aNDFom; 330 g/kg vs. 425 g/kg). Controls were made during two consecutive experimental periods that differed in hygienic environmental conditions by modifying the intensity of cleaning and disinfection in the farm previous to the trial. An interaction (P<0.001) was detected among the independent variables studied on Cl. perfringens enumeration in the caecal contents, as minimal values for this trait were obtained in non-medicated animals reared in a clean environment, and especially when they were weaned at a later age and fed the diet with the lower fibre content. The treatments studied also led to a variation in fattening mortality (from 4.7% to 34.0%), which was highly and positively correlated (P<0.001) to the average Cl. perfringens caecal counts in each combination of treatments. The results of the current study indicate that high counts of Cl. perfringens in the caecum can be used as an indicator of Epizootic Rabbit Enteropathy, and suggest that strategies designed to control its proliferation in the caecum might help to limit fattening mortality in rabbit fed diets not-medicated with antibiotics.

Meta-analysis of the influence of Saccharomyces cerevisiae supplementation on ruminal parameters and milk production of ruminants

The effects of yeast supplementation on intake, production, and rumen fermentation characteristics have been widely studied, but results are inconsistent between different studies. A quantitative meta-analysis was applied to 110 papers, 157 experiments, and 376 treatments dealing with yeast supplementation in ruminants. The objective was first to highlight the major quantitative effects of live yeast supplementation on intake, rumen fermentation, and milk production, and second, to identify major differences in experimental conditions between studies that can affect the response to treatment. Some of these experimental conditions are referred to as interfering factors. Yeast supplementation increased rumen pH (+0.03 on average) and rumen volatile fatty acid concentration (+2.17mM on average), tended to decrease rumen lactic acid concentration (−0.9mM on average), and had no influence on acetate-to-propionate ratio. Total-tract organic matter digestibility was also increased by yeast supplementation (+0.8% on average). Yeast supplementation increased dry matter intake (DMI;+0.44g/kg of body weight; BW), milk yield (+1.2g/kg of BW), and tended to increase milk fat content (+0.05%), but had no influence on milk protein content. Dose effects of yeast supplementation, expressed as log10 [1+(cfu per 100kg of BW)], globally confirmed the qualitative effects observed in the first analysis. The positive effect of yeast supplementation on rumen pH increased with the percentage of concentrate in the diet and with the DMI level. It was negatively correlated with the level of dietary neutral detergent fiber (NDF). The positive effect of yeast supplementation on rumen volatile fatty acid concentration increased with DMI and crude protein levels. The positive effect of yeast supplementation on organic matter digestibility increased with the percentage of concentrate and NDF in the diet. The negative effect of yeast supplementation on lactic acid concentration tended to decrease when the DMI level and the percentage of concentrate in the diet increased. The effects of interfering factors were globally similar when either dose effect or qualitative effect of yeast was taken into account. Although rumen fermentation efficiency per se was not measured, these results suggest an improvement in rumen fermentation by yeast supplementation. This effect could, however, be modulated by several different factors such as DMI, percentage of concentrate or NDF in the diet, or species.

Diet composition, food intake, body condition, and fecal consistency in captive tapirs (Tapirus spp.) in UK collections

Intake measurements were carried out in 22 tapirs from seven UK zoological collections. Dry matter intake (DMI) ranged from 48 to 86 g/kg(0.75)/d. Across collections, the highest proportion of the ingested diet consisted of pelleted feeds (including grains and bread) at 46+/-17% DMI, followed by commercial produce at 26+/-12% DMI, roughage (excluding browse) at 17+/-11% DMI, and browse at 11+/-11% DMI. The proportion of roughage, crude protein, crude fiber, and neutral detergent fiber levels in the diets investigated were well below levels recommended for domestic horses and other ungulates. Intakes of digestible energy (DE) as estimated from food nutrients using of a standard equation for domestic horses ranged from 0.58 to 0.88 MJ/DE/kg(0.75)/d, with many individuals exceeding the assumed maintenance requirement of 0.6 MJ/DE/kg(0.75)/d for hindgut fermenters. At values exceeding this DE intake, animals had higher than ideal body condition scores (BCS). Animals with higher BCS (i.e. more obese animals) generally had higher fecal scores (FS) (i.e. softer feces), and both BCS and FS were positively correlated to DMI and calculated DE intake. This suggests that the population studied was generally overfed, with resulting obesity and softer fecal consistency. The use of highly digestible feeds such as commercial produce and pelleted feeds should be restricted in the diets of these animals and roughage intake promoted in order to attempt to achieve normal BCS and FS in this captive population.