Levels Of Neutral Detergent Fiber Research Articles

Effect of fibre supplementation on dag formation and flystrike in sheep grazing spring pastures

Sheep on spring pastures may scour excessively due to the low levels of neutral detergent fibre. Scouring leads to dag formation, which predisposes sheep to flystrike, particularly in the breech area, posing a considerable challenge to sheep producers. This trial was undertaken to test whether supplementing sheep on spring pasture with fibre would reduce diarrhoea and thereby reduce dag formation and flystrike. Four hundred first-lambing Merino ewes were randomly allocated to control (no fibre supplementation) and fibre treatment (ad libitum cereal hay or wheat straw supplementation) groups in a 2-paddock crossover trial, which was conducted from August through the spring flush to crutching in October. The bulk fecal egg counts of each group were no different at the start of the trial but the fibre group had a higher (P<0.05) fecal egg count than the control at crutching. Fecal egg count was not correlated with dag score. Fecal dry matter percentage was higher (P<0.05) in the fibre group but there was no difference in dag wet weight or dry matter percentage between the treatment groups. Dag scores of a sample of 100 sheep from each group were significantly (P<0.01) lower at crutching. There was no difference between the groups in the incidence of flystrike, however, there were significantly (P<0.001) more sheep with high dag scores (>3) in the control group than the fibre treatment group. These results indicate that the supplementation of spring pasture with low quality hay or straw can reduce dag formation by improving the consistency of feces and, thereby, reduce the number of sheep with dag scores greater than 3.

Efeito da adição de níveis crescentes de polpa cítrica sobre a qualidade fermentativa e o valor nutritivo da silagem de capim-elefante

Foram estudados os efeitos da adição de polpa cítrica sobre a qualidade fermentativa e o valor nutritivo da silagem de capim-elefante. O capim-elefante, apresentando 90 dias de crescimento, foi ensilado com níveis crescentes de polpa cítrica peletizada: 0; 2,5; 5; 7,5; 10; 12,5 e 15%, com base na matéria fresca. As silagens foram produzidas em 28 silos experimentais (quatro repetições/tratamento), confeccionados a partir de baldes plásticos com válvulas do tipo Bunsen. A abertura dos silos ocorreu 106 dias após a ensilagem, quando foram determinados os teores dos ácidos orgânicos e a composição químico-bromatológica das silagens. Foi observado efeito linear crescente da adição de polpa cítrica sobre os teores de matéria seca, o mesmo ocorrendo para carboidratos solúveis e digestibilidade in vitro da matéria seca, mas com redução nos teores de nitrogênio amoniacal e fibra em detergente neutro. Para os teores de ácidos orgânicos (acético, lático e butírico) e etanol, observou-se comportamento quadrático para as curvas obtidas, com pontos de máxima para o ácido lático igual a 5,8% e de mínima para os ácidos acético, butírico e o etanol, iguais a 7,8; 7,2; e -3,7% de polpa, respectivamente. Não foram observados efeitos sobre os valores de pH, assim como para os teores de lignina e de ácido propiônico. Inclusões de 4,7 a 7,6% de polpa cítrica peletizada, com base na matéria fresca, são suficientes para melhorar a qualidade e o valor nutritivo da silagem de capim-elefante.

In vitro studies on microbial efficiency from two cuts of ryegrass ( Lolium perenne, cv. Aberdart) with different proportions of sugars and protein

An in vitro study investigated effects on microbial efficiency of feeding ryegrass diets differing in water soluble carbohydrates (WSC) and crude protein (CP) levels. A 1st cut of a diploid ryegrass (Aberdart) with high WSC-low CP (Cut1), a 2nd cut with low WSC-high CP (Cut2) contents and the two cuts, supplemented with mainly casein or fructans + sucrose (Cu1P and Cut2S) to achieve similar WSC and CP levels, were used. Dietary levels of WSC, CP and neutral detergent fibre (NDFom) were (in g/kg dry matter): 298, 100, 464 (Cut1), 101, 179, 484 (Cut2), 290, 181, 401 (Cut1P) and 290, 181, 351 (Cut2S), respectively. The in vitro system (SIMCO) was a repeatedly fed semi-continuous culture allowing stratification of vessel contents and selective retention of feed particles. The estimated NDFom in sacco degradation rate (h −1) and indigestible NDFom (INDFom) was 0.042 and 0.117 for the 1st cut and 0.086 and 0.270 for the 2nd cut. Digestibility of NDFom in SIMCO tended to be higher in the 1st cut than in the 2nd cut diets. Fermentation patterns were in normal rumen ranges. Ribonucleic acid (RNA) and volatile fatty acid (VFA) efficiencies (g/kg truly digested organic matter) differed among treatments (P=0.005 and P=0.018, respectively). Statistical significance at P<0.05 was only achieved for Cut1P vs Cut2 and Cut2S (RNA efficiency) and for Cut1P vs Cut2S (VFA efficiency). Molar proportions of acetate were lower and propionate higher in 1st cut, compared to 2nd cut diets (P<0.05). Mean retention time (MRT) of the liquid fraction was fixed at 10.4 h, but MRT of INDFom was long, varying from 95 to 303 h and strongly influenced by the daily supply of INDFom in the different diets, which was approximately twice as high in the 2nd as compared to the 1st cut diets. This resulted in a strong negative relationship between RNA efficiency and MRT. Microbial N and VFA efficiency in the SIMCO system is likely to be more dependent on solids retention time than on the relatively wide range of WSC and CP levels used in this study. To evaluate diets with respect to microbial efficiency, fermentation system must have the possibility to separate effects substrates from digesta retention under near rumen-like conditions.

Stem characteristics of two forage maize ( Zea mays L.) cultivars varying in whole plant digestibility. II. Relation between in vitro rumen fermentation characteristics and anatomical and chemical features within a single internode

Internode 7 of the stem of two forage maize ( Zea mays L.) cultivars was studied anatomically and chemically at anthesis and subjected to fermentation tests in rumen fluid, using an automated gas production system. For anatomical studies internode 7 was sectioned at the top, middle and base. For chemical analyses and fermentation studies, the internode was divided into five sections. The number of scle-renchyma layers increased from top to base of the internode, whereas cell wall thickness of the scle-renchyma decreased from top to base. The highest and lowest sections of the internode had a higher sugar content and lower levels of neutral detergent fibre, acid detergent fibre, and acid detergent lignin, and slightly higher levels of crude protein than the middle three sections. Also their hemicellulose and cellulose contents were different but the differences with the middle three sections were small. Maximum gas production from fermentation in rumen fluid was higher for cell wall material from the highest and lowest than from the middle three sections. This was mainly due to differences in chemical composition: the highest and lowest section had a higher lignin and a relatively high hemicellulose content compared with the middle three sections. Digestibility of the cultivar with the higher whole plant digestibility, Vitaro, exceeded that of the cultivar Volens for each of the sections examined within the selected internode. Secondary cell wall disappearance was only weakly correlated with lignin content or gas production. This suggests that other factors are important in the fermentation process. These may include anatomical factors influencing the accessibility of the tissues to micro-organisms and chemical and/or physical factors such as lignin composition, lignin localization within the cell wall and nature and extent of cross-linking lignin to other cell wall components.

Effects of Swine Lagoon Effluent Relative to Commercial Fertilizer Applications on Warm‐Season Forage Nutritive Value

Two field experiments were conducted to evaluate the effects of comparable rates of swine lagoon effluent and commercial fertilizer at different harvest dates on dry matter yield and nutritive value of bermudagrass (Cynodon dactylon L.) grown on an acid Vaiden silty clay (very fine, montmorillonitic, thermic, Vertic Hapludalf) and johnsongrass (Sorghum halepense L.) grown on an alkaline Okolona silty clay (fine, montmorillonitic, therimic, Typic Chromudert). At each site, a randomized complete block design with a factorial arrangement of treatments replicated four times was used. Treatments were multiple effluent irrigations resulting in four N rates from 0 to 665 kg N ha−1 yr−1. In each block, commercial fertilizer (N, P, and K) treatments were applied to additional plots at rates equivalent to swine effluent rates. Total dry matter yield and crude protein (CP) for bermudagrass and johnsongrass reached a plateau with application of approximately 450 kg N ha−1 from either swine effluent or commercial fertilizer. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) peaked at the low fertilization rate and then declined with increasing effluent and commercial fertilizer rates. An inverse relationship was obtained for in vitro true digestibility (IVTD) in response to fertilization rate for both grasses. Forage dry matter, CP, NDF, and ADF levels peaked in the July harvest and then declined, but forage IVTD level declined in July harvest. Only in July 1996, forage NO3–N concentration was lower for swine effluent than commercial fertilizer. Swine effluent and commercial fertilizer had similar effects on forage dry matter yield and nutritive value.

Predicción de la composición química del grano de sorgo mediante espectroscopía de reflectancia cercana al infrarrojo (NIRS)

In the calibration of a near infrared spectroscopy (NIRS) device to predict the chemical composition of sorghum grain, 216 sorghum grain samples were used throughout three years (1996, 1997 y 1998). Density, moisture, crude protein, neutral detergent fiber (NDF), and tannin contents were measured by determining sample NIRS spectrum using a 19-discrete-filter NIRS machine. Chemical results were subjected to a descriptive statistical analysis (average, minimum, maximum, standard deviation, and coefficient of variation). Samples from each year were compared using a totally-at-random design. Regarding tannin contents, statistically significant differences (P 0.05), with an average of 8.18 %. The coefficient of determination (R2) of NIRS regression equations was high for moisture (0.96), crude protein (0.93), and NDF (0.74) contents. Two equations were developed in order to predict tanning contents. The first equation was for low tannin sorghum samples (0.12 to 0.45 %). The second equation corresponded to sorghum samples containing 0.47 to 1.07 % tannins. Both equations had low R2 values (0.58 and 0.52, respectively). We concluded that NIRS was able to predict the levels of moisture, crude protein, and NDF. Tannin content prediction is yet to be improved.

Nutritive Quality of Cool‐Season Grass Monocultures and Binary Grass–Alfalfa Mixtures at Late Harvest

Nutritive quality of hay is compromised when harvest is delayed, but reproduction of upland nesting birds in the northern Great Plains would be improved if haying operations could be deferred until mid‐July or later to allow completion of nesting. This study was conducted to determine nutritive quality of hay at a single mid‐July cutting from three cool‐season grass species that were grown in monoculture and in binary mixtures with alfalfa [Medicago sativa subsp. × varia (Martyn) Arcang.] near Mandan, ND. Grasses were intermediate wheatgrass [Thinopyrum intermedium (Host) Barkw. &amp; Dewey], smooth bromegrass (Bromus inermis Leyss.), and crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.]. Annual applications of 0 and 50 kg N ha−1 had no effect on in vitro dry matter digestibility (IVDMD) or neutral detergent fiber (NDF) levels of grass or alfalfa. Grass monocultures and alfalfa averaged 612 and 624 g kg−1, respectively, for IVDMD and 651 and 567 g kg−1, respectively, for NDF. At 0 kg N ha−1, crude protein (CP) ranged from 71 to 78 g kg−1 in grass monocultures and from 92 to 131 g kg−1 in grass–alfalfa mixtures. At 50 kg N ha−1, CP ranged from 83 to 97 g kg−1 in grass monocultures and from 99 to 133 g kg−1 in mixtures. Feasibility of deferring hay harvest to allow reproduction of upland nesting birds in the northern Great Plains depends on maintaining alfalfa or other legumes with high nutritive quality in grass mixtures to reduce NDF and increase CP levels.

Remoção de polifenóis da farinha de folhas de mandioca

A farinha de folhas de mandioca apresenta baixa digestibilidade, mesmo possuindo um teor relativamente elevado em proteínas, principalmente, devido à presença de substâncias como os polifenóis. Visando melhorar o aproveitamento protéico desta farinha, empregaram-se três solventes (água, etanol 50mL/100mL e hidróxido de amônio 1mol/L) para remover os polifenóis. Folhas maduras de mandioca foram coletadas na fase vegetativa, em três repetições, colocadas em bandejas de papel e secas à sombra sobre bancadas de madeira, em recinto fechado e arejado, em temperatura ambiente. Após secagem, retiraram-se os pecíolos e as folhas foram moídas e passadas em peneira de 40mesh. A farinha foi submetida, antes e após a remoção dos polifenóis, às análises de umidade, fibra detergente neutra (FDN), fibra detergente ácida (FDA), açúcares totais, proteína bruta, vitamina C total, beta-caroteno, cianeto, inibidor de tripsina, polifenóis e digestibilidade protéica in vitro. Após remoção dos polifenóis, houve diminuição dos teores de açúcares totais, vitamina C total, inibidor de tripsina e polifenóis e aumento de FDN, FDA, proteína bruta, beta-caroteno e digestibilidade protéica in vitro. Dos solventes empregados para remover polifenóis, o hidróxido de amônio foi o mais eficaz, com índice de remoção de 94%, seguido pelo etanol (83%) e água (65%). A digestibilidade da proteína in vitro aumentou em 74%, quando o solvente empregado na remoção dos polifenóis foi o hidróxido de amônio.

Efeito de aditivos biológicos comerciais na silagem de capim-elefante (Pennisetum purpureum Schum)

Avaliaram-se o pH e a composição bromatológica de silagens de capim-elefante var. Napier, sem e com três aditivos biológicos comerciais (B, C e D) em duas concentrações de diluição, a recomendada pelo fabricante (concentração 1) ou com o dobro (concentração 2), feitas em microsilos de PVC. O delineamento experimental foi inteiramente ao acaso, com sete tratamentos e seis repetições por tratamento. Apenas o aditivo B em ambas as concentrações (3,73; 4,07) foi eficiente em reduzir (P&lt;0,05) o pH em relação ao tratamento-controle (5,01). A porcentagem de matéria seca aumentou (P&lt;0,05) com o uso do aditivo B, nas concentrações 1 (29,9) e 2 (31,3), e dos aditivos C e D, na concentração 2 (26,8; 25,7). Quanto à proteína bruta, somente houve diferença (P&lt;0,05) entre o tratamento-controle (6,6) e os dois tratamentos com aditivo B (13,4; 12,09). As frações de fibra em detergente neutro e lignina foram menores (P&lt;0,05) nos tratamentos com aditivo B em relação ao tratamento-controle. A duplicação da dose do aditivo B não aumentou sua eficiência. Nos macro-elementos cálcio e fósforo das silagens, todos os aditivos elevaram a concentração de cálcio e não alteraram a de fósforo. Concluiu-se que o aditivo B, constituído de Lactobacillus plantarum e Pediococcus acidilactici, melhorou tanto a qualidade de fermentação quanto o valor nutritivo da silagem de capim-elefante, e que a duplicação da concentração dos produtos não aumentou (P&lt;0,05) a qualidade das silagens.

The effects of processing at harvest and cutting height of urea-treated whole-crop wheat on performance and digestibility in dairy cows

AbstractUrea-treated whole-crop wheat harvested at growth stage (GS) 87 that was either unprocessed (U) or processed (P) by the forage harvester, and cut at one of two heights to produce a long straw (L), or short straw (S) forage, was offered to 44 Holstein-Friesian dairy cows for 14 weeks according to a 2 ✕ 2 factorial design. Whole-crop wheat (WCW) was mixed 2: 1 on a dry-matter (DM) basis with grass silage and all animals received 8·5 kg/day of concentrate and 2 kg/day of rapeseed meal. Increasing the cutting height at harvest increased the starch content in the forage from an average of 356 to 419 g/kg DM and decreased neutral-detergent fibre levels from 422 to 337 g/kg DM. Forage intake (grass silage and WCW) was higher in cows given the unprocessed compared with the processed forages (13·7 v. 12·5 kg DM per day for treatments U v. P respectively; P &lt; 0·05) and tended (P &lt; 0·08) to be higher in cows given the long compared with the short straw forages. Neither processing, nor alteration of cutting height, had a significant effect on milk yield (kg/day). However, milk fat content decreased (P &lt; 0·05) with increasing cutting height (41·9 v. 37·0 g/kg for the main effects of L v. S respectively) whilst body condition score was lower (P &lt; 0·05) in cows given the long compared with the short straw forages (2·6 v. 2·8 respectively). Plasma glucose levels were higher (P &lt; 0·05) in animals receiving the short compared with long straw forages (3·52 v. 3·34 mmol/l respectively) whereas β-hydroxybutyrate decreased (P &lt; 0·01) with increased cutting height. The average digestibility of starch in the total ration was higher (P &lt; 0·001) in cows given the processed compared with the unprocessed WCW (0·96 v. 0·88 respectively). Assuming a constant apparent digestibility of starch in the other food components resulted in a WCW starch apparent digestibility of 0·87, 0·97, 0·80 and 0·96 for forages LU, LP, SU and SP respectively (P &lt; 0·001). The results indicate that processing at harvest significantly increased the digestibility of starch in WCW and that cows responded to this higher nutrient content by decreasing forage intake. Increasing the cutting height at harvest decreased milk fat content (g/kg) and yield (kg/day) and increased body condition score.

Effects of Neutral Detergent Fiber Concentration and Particle Size of the Diet on Chewing Activities of Dairy Cows

Six dry Holstein cows were used to evaluate the effect of dietary neutral detergent fiber (NDF) concentration and particle size (PS) on chewing activity. Treatments were arranged in a 3×3 factorial design; total mixed rations contained three NDF concentrations (26, 32, 38%) and three PS (1.0, 1.5, 2.0 cm). NDF levels and particle sizes of diets were adjusted by formulating rate and cutting length of alfalfa hay and rice straw. Cows were fed twice daily at 90% of ad libitum feed intake throughout the experiment. Chewing activity was positively associated with NDF concentration, but not significantly affected by PS of diet. Eating time per unit of NDF intake was affected by PS rather than NDF concentration of diet. Time spent ruminating per unit DM or NDF intake increased with increasing NDF concentration of diet, but was not affected by PS. As the PS of diet increased, the eating time per day increased, but the rumination time decreased. In addition, as the number of rumination bolues decreased the rumination duration increased as well as the chews per bolus. The regression equation induced from relationships of NDF concentrations (NDF, %) and particle sizes (PS, cm) of diet on roughage value index (RVI, min of chewing time/kg DMI) was as follows. RVI=-19.672+1.44×NDF+5.196×PS, (r 2 =0.81). (Asian- Aust. J. Anim. Sci. 2004. Vol 17, No. 11 : 1535-1540)

Consumo de fibra em detergente neutro por bovinos em confinamento

Objetivou-se avaliar o consumo de fibra em detergente neutro (FDN) por bovinos em confinamento e os principais fatores que influenciam esta variável, correlacionado-a ao consumo de matéria seca (MS) total. Foram avaliados dados publicados na Revista da Sociedade Brasileira de Zootecnia e Revista Brasileira de Zootecnia, no período de 1991 e 2000, totalizando 45 trabalhos científicos e 181 médias de tratamentos. O nível de nutrientes digestíveis totais mostrou-se negativamente correlacionado ao nível de FDN nas dietas (r = -0,6006; P&lt;0,01). A concentração de carboidratos não-fibrosos influenciou de forma negativa a digestibilidade da FDN (DFDN) (r = -0,1631; P&lt;0,09); contudo, nenhum procedimento estatístico empregado permitiu detectar efeitos da DFDN sobre o consumo de MS total (P&gt;0,10). A descrição da relação entre consumo de MS e nível de FDN na dieta foi realizada de forma bifásica, buscando similaridade às curvas propostas por um modelo estático de predição do consumo. A interseção das curvas projetou consumo de FDN (CFDN) de 11,93 g/kg PV. No entanto, a avaliação dos CFDN estimados durante a fase atribuída aos controladores físicos do consumo mostrou inconstância, gerando divergência entre os pontos de consumo máximo de MS e FDN, indicando ser a transição entre os mecanismos físicos e fisiológicos, possivelmente, determinada por um intervalo com interação entre mecanismos. A avaliação do CFDN em função do nível de volumosos nas dietas mostrou perfis estáveis em concentrações superiores a 60%, sendo de 13,53 g/kg PV no intervalo de 80 a 100%. Possíveis interações com a fração indigestível da FDN podem ditar a plasticidade do limite diário de CFDN.

Characteristics and in situ degradability of whole crop faba bean, pea, and soybean silages

The objective of this study was to determine the ensiling characteristics and ruminal nutrient degradabilities of faba bean (FS, Vicia faba L.), soybean (SS, Glycine max (L.) Merr.) and pea (PS, Pisum sativum L.) silages. Forages were harvested between the beginning- and full-seed stages and ensiled in mini-silos for 0, 2, 4, 16, and 45 d. Two lactating Holstein cows fitted with ruminal fistulae were used to determine ruminal nutrient degradabilities. Results showed that all silages went through a rapid fermentation as indicated by rapid decline in pH and sharp increase in lactic acid concentration within the first 2 d of ensiling. Extensive proteolysis took place between day 0 and day 4 post-ensiling as indicated by a significant reduction in true protein (TP) and a significant increase in non-protein nitrogen (NPN). During the 45 d of ensiling, TP decreased (P &lt; 0.05) by 26, 31, and 45% while NPN increased (P &lt; 0.05) by 82, 54, and 47% for FS, SS, and PS, respectively. Chemical analysis showed that the three 45-d silages contained a similar level of neutral detergent fiber (NDF, average 421 g kg-1). Crude protein (CP) was highest (P &lt; 0.05) for FS, intermediate for SS, and lowest for PS. Distribution of protein fractions showed that soluble protein and NPN were highest (P &lt; 0.05) for PS, intermediate for SS, and lowest for FS. Neutral (NDICP) and acid (ADICP) detergent insoluble protein levels followed an opposite order to that observed for soluble crude protein (SCP) and NPN. Results of the in situ study showed that SS and PS had a similar ruminal degradability of dry matter (average 68.8%) and CP (82.9%), which were higher (P &lt; 0.05) than those of FS (66.2 and 79.4%, respectively). However, no differences in ruminal degradability of NDF (average 34.7%) were observed between the three legume silages. Key words: Silage, ensiling, forage quality, nutrient degradability

Forage evaluation, chemical composition, and in vitro digestibility of continuously grazed star grass

This study evaluated the chemical composition and dry matter (DM) digestibility of leaf, stem, and senescent fractions of star grass (Cynodon plectostachyus Pilger) in summer and winter in the south of Brazil. Four 17.6 ha pastures grazed by growing steers in continuous grazing were used. The experiment was divided into two periods: (I) summer: February to June, when five cuts were made; (II) winter: June to October, with six cuts. The forage samples were collected at nine pasture points every 28 days. The DM availability reduced linearly in the summer. In the winter, after September there was a recovery of DM availability. In the summer, there was a linear reduction in leaf proportion and a linear increase in senescent fraction. In the winter, there was a reduction in stem proportion and the senescent fraction increased. Leaf proportion had a quadratic response. The mean crude protein (CP) levels, neutral detergent fiber (NDF), and acid detergent fiber (ADF) during the summer in the leaves were 11.8, 68.6 and 36.1%. The levels were 5.5, 79.3 and 48.8% for stems and the levels were 3.6, 83.0 and 50.2% for the senescent fraction. During the winter, the average levels of CP, NDF and ADF in the leaves were 12.9, 62.2 and 32.7%. The levels were 4.7, 81.2 and 50.1% for stems and 4.1, 84.6 and 54.0% for the senescent fraction. The percentage of indigestible CP in relation to CP was 20% for leaves, 74% for the senescent fraction, and there was variation with time for the stems with levels between 20 and 90%. The DM digestibility of the forage during the summer had a linear reduction and a quadratic behavior during the winter with an average level of 54% in the summer and 42% in the winter.

Effects of Varying Dietary Protein and Energy Levels on the Production of Lactating Dairy Cows

Forty-five multiparous and 18 primiparous Holstein cows were fed three levels of crude protein (CP), each at three levels of neutral detergent fiber (NDF), to identify optimal dietary CP and energy. Cows were blocked by parity and days in milk into seven groups of nine and randomly assigned to an incomplete 9×9 Latin square trial with four, 4-wk periods. Diets were formulated from alfalfa and corn silages, high-moisture corn, soybean meal, minerals, and vitamins. Forage was 60% alfalfa and 40% corn silage on all diets; NDF contents of 36, 32, and 28% were obtained by feeding 75, 63, and 50% forage, respectively. Dietary CP contents of 15.1, 16.7, and 18.4% were obtained by replacing high-moisture corn with soybean meal. Production data were from the last 2wk of each period. Spot fecal and urine samples were collected from 36 cows to estimate N excretion using fecal indigestible acid detergent fiber (ADF) and urinary creatinine as markers. There were no interactions (P≥0.08) between dietary CP and NDF for any trait; thus, effects of CP were not confounded by NDF or vice versa. Intake of DM and fat yield were lower on 15.1% CP than at higher CP. There were linear increases in milk urea and urinary N excretion and linear decreases in N efficiency with increasing CP. Increasing CP from 15.1 to 18.4% reduced milk N from 31 to 25% of dietary N, increased urinary N from 23 to 35% of dietary N, and reduced fecal N from 45 to 41% of dietary N. Decreasing NDF gave linear increases in BW gain, yield of milk, protein, true protein, lactose, and SNF, and milk/DM intake and milk N/N intake, and linear decreases in milk urea. However, fat yield was lower on 28% than 32% NDF. Reducing NDF from 36 to 28% increased purine derivative excretion by 19%, suggesting increased microbial protein. Increasing CP by adding soybean meal to diets fed cows averaging 34kg/d of milk increased intake and fat yield but depressed N efficiency. Increasing dietary energy by reducing forage improved milk yield and efficiency and decreased excretion of environmentally labile urinary N.

Date and Plant Community Effects on Elk Sedge Forage Quality

Elk sedge (Carex geyeri Boott) is one of the most important livestock and big game forages in many areas of the western U.S. It is one of the most prominent forage species in the diets of cattle and elk utilizing forested rangelands. Despite its acknowledged ecological and economical importance, very little is known about the factors influencing the forage quality of elk sedge. Effects of sampling date, plant community, and their interaction on the neutral detergent fiber, acid detergent fiber, and crude protein levels of elk sedge are reported for samples collected at the Starkey Experimental Forest and Range and the Bridge Creek Wildlife Management Area, both in northeastern Oregon, during January, April, July, and October of 1997 and 1998. Neutral detergent fiber levels in elk sedge were lowest in mid-October (average = 71.3%) and highest in mid-July (average = 76.1%). Acid detergent fiber was lowest in elk sedge collected in mid-October (average = 37.3%) and highest in mid-July (average = 39.0%) and mid-January (average = 39.2%). Elk sedge from the Douglas-fir/ninebark community was lowest in acid detergent fiber (average= 38.1%). Crude protein was highest (average = 8.0%) in mid-July elk sedge samples and lowest (average = 5.7%) in mid-January samples. Elk sedge from the ponderosa pine/fescue community was lowest in crude protein (average = 5.9%). All forage quality parameters exhibited variability between years. Although sampling date and plant community effects were detected, the forage quality of elk sedge appeared relatively stable compared to other native forages. A more intensive spring sampling campaign is needed to characterize the relationship between elk sedge phenology and forage quality dynamics. DOI:10.2458/azu_jrm_v56i1_clark

Date and plant community effects on elk sedge forage quality

Elk sedge (Carex geyeri Boott) is one of the most important livestock and big game forages in many areas of the western U.S. It is one of the most prominent forage species in the diets of cattle and elk utilizing forested rangelands. Despite its acknowledged ecological and economical importance, very little is known about the factors influencing the forage quality of elk sedge. Effects of sampling date, plant community, and their interaction on the neutral detergent fiber, acid detergent fiber, and crude protein levels of elk sedge are reported for samples collected at the Starkey Experimental Forest and Range and the Bridge Creek Wildlife Management Area, both in northeastern Oregon, during January, April, July, and October of 1997 and 1998. Neutral detergent fiber levels in elk sedge were lowest in mid-October (average = 71.3%) and highest in mid-July (average = 76.1%). Acid detergent fiber was lowest in elk sedge collected in mid-October (average = 37.3%) and highest in mid-July (average = 39.0%) and mid-January (average = 39.2%). Elk sedge from the Douglas-fir/ninebark community was lowest in acid detergent fiber (average= 38.1%). Crude protein was highest (average = 8.0%) in mid-July elk sedge samples and lowest (average = 5.7%) in mid-January samples. Elk sedge from the ponderosa pine/fescue community was lowest in crude protein (average = 5.9%). All forage quality parameters exhibited variability between years. Although sampling date and plant community effects were detected, the forage quality of elk sedge appeared relatively stable compared to other native forages. A more intensive spring sampling campaign is needed to characterize the relationship between elk sedge phenology and forage quality dynamics.

Dietary fibre level and enzyme inclusion affect nutrient digestibility and excreta characteristics in grower pigs

AbstractAn experiment was conducted with 12 grower pigs to determine the effects of (1) manipulating dietary neutral detergent fibre (NDF) level and (2) dietary inclusion of fibre‐degrading enzymes on nutrient digestibility and excreta characteristics in pigs. Four diets were formulated to contain three levels of NDF: 1, 66 g kg−1 NDF (low fibre); 2, 121 g kg−1 NDF (moderate fibre); 3, 222 g kg−1 NDF (high fibre); 4, diet 3 plus 2.0 g kg−1 enzyme. Increasing levels of dietary NDF linearly decreased dry matter and energy digestibilities (r2 = 0.99, P &lt; 0.05). Lowering dietary NDF from 222 to 121 g kg−1 improved nitrogen digestibility by 13% (P &lt; 0.01). Faecal production was decreased by 9% for each 1% decrease in dietary NDF content (r2 = 0.99, P &lt; 0.05). Inclusion of fibre‐degrading enzymes in the high‐fibre diet improved dry matter and energy digestibilities by 2 and 3% respectively, and reduced faecal production by 10% (P &lt; 0.01). Faecal and manure (faeces plus urine) pH values from pigs fed the high‐fibre diet and the high‐fibre plus enzyme diet were lower than those from pigs fed the other experimental diets (P &lt; 0.05). In conclusion, lowering the dietary NDF level or inclusion of fibre‐degrading enzymes in high‐fibre diets may offer relatively practical and easy methods for reducing waste production in pigs.© 2002 Society of Chemical Industry

Produção e qualidade de folhas de amoreira em função da época do ano e de colheita

A quantidade e qualidade das folhas de amoreira (Morus alba L.) exercem influência marcante sobre o desenvolvimento do bicho-da-seda e são, por sua vez, influenciadas por fatores como a idade das folhas, época do ano e características genéticas dos cultivares. Avaliou-se a produção e a qualidade nutricional de folhas de cinco cultivares de amoreira em diferentes épocas do ano e de colheita, objetivando verificar sua adaptação na região de Jaboticabal (SP). As folhas dos cultivares 'Miura', 'Korin', 'Calabresa', 'FM86' e 'FM Shima-Miura' foram colhidas na primavera, verão e outono após 45, 60, 75 e 90 dias da poda (DAP) e avaliadas quanto à produção de folhas níveis de proteína bruta (PB) e fibra em detergente neutro (FDN). As melhores produções foram verificadas em 'FM Shima-Miura', principalmente aos 75 DAP na primavera e no verão e aos 90 DAP no outono. No verão, as colheitas efetuadas aos 60, 75 e 90 DAP resultaram em produções mais elevadas. As épocas de colheita que resultaram em maiores níveis de PB foram aos 45 e 60 DAP e em menores níveis de FDN aos 60 DAP, respectivamente. Foi possível conciliar altos níveis de PB, baixos níveis de FDN e relativamente alta produção de massa foliar somente na colheita efetuada aos 75 DAP.

Chemical composition, ruminal kinetic parameters, and nutrient digestibility of ammonia treated oat hulls

A study was conducted to determine the effects of ammoniation (3 or 5% by dry weight) on the nutritive value of oat hulls. Ruminal nutrient kinetic parameters and degradability of untreated and ammoniated oat hulls were determined using two non-lactating cows fitted with rumen cannulas. Eighteen steers were used in a digestibility trial to determine nutrient utilization of three diets consisting of 100% barley silage, 50% untreated oat hulls plus 50% barley silage, and 50% ammoniated oat hulls plus 50% barley silage (DM basis). Ammoniation at both levels increased (P &lt; 0.05) total N and reduced (P &lt; 0.05) neutral detergent fibre levels of oat hulls. Most of the N added due to ammoniation was in the form of non-protein N. The results of the in situ trial showed that ammoniation at the 3% level increased the potentially degradable NDF and ADF fractions as well as their rates of degradation. Ammoniation at the 3% level improved (P &lt; 0.05) effective ruminal degradability of NDF and ADF of oat hulls by 41 and 35%, respectively. Dry matter intake was highest (P &lt; 0.05) for steers fed the ammoniated oat hull diets, intermediate for those fed the untreated oat hull diets and lowest (P &lt; 0.05) for those fed the 100% barley silage diet. Steers fed the ammoniated oat hull diet had higher (P &lt; 0.05) total tract digestibility of NDF and lignin relative to steers fed the untreated oat hull diet. However, total tract digestibility of dry matter was not affected by ammoniation. It was concluded that ammoniation is a viable method for improving the feeding value of oat hulls to ruminant animals. Relative to the 3% level, ammoniation at 5% resulted in a marginal improvement in the nutritive value of oat hulls. Key words: Ammonia treatment, oat hulls, ruminal degradation, nutrient utilization