Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Biorefinery methods for separation of protein and oil fractions from rubber seed kernel
    Widyarani, R. ; Ratnaningsih, E. ; Sanders, J.P.M. ; Bruins, M.E. - \ 2014
    Industrial Crops and Products 62 (2014). - ISSN 0926-6690 - p. 323 - 332.
    aqueous enzymatic extraction - supercritical carbon-dioxide - hevea-brasiliensis seeds - biodiesel production - functional-properties - alpha-lactalbumin - nutritive-value - amino-acids - products - recovery
    Biorefinery of rubber seeds can generate additional income for farmers, who already grow rubber trees for latex production. The aim of this study was to find the best method for protein and oil production from rubber seed kernel, with focus on protein recovery. Different pre-treatments and oil separation methods were tested, and alkaline conditions were used to extract protein. Next to processes with subsequent oil and protein recovery, a one-step combined oil and protein extraction was tested. Our study showed that oil separation is not necessary to obtain high protein recovery, however most of the extracted oil is present as an emulsion. The origin of the seeds and their treatment on the plantation before processing were most important for high oil and protein recoveries, and in all cases tested had more influence on recoveries than its subsequent method of processing. Pressing the rubber seed kernel to separate the oil fraction followed by protein extraction from the press cake gives the highest protein recovery with satisfactory recovery for oil.
    The effect of steam pelleting of a dry dog food on the Maillard reaction
    Rooijen, C. van; Bosch, G. ; Wierenga, P.A. ; Hendriks, W.H. ; Poel, A.F.B. van der - \ 2014
    Animal Feed Science and Technology 198 (2014). - ISSN 0377-8401 - p. 238 - 247.
    glycation end-products - physical quality - nutritive-value - animal feed - lysine - diet - digestibility - absorption - components - proteins
    During processing of pet foods, the Maillard reaction (MR) can occur, which reduces the bioavailability of essential amino acids like lysine and results in the formation of advanced Maillard reaction products (MRPs). This study examined the effect of conditioning temperature (65 and 90 °C) and die hole length (ø 5 × 45, 65, and 80 mm) during pelleting processing of a standard dry dog food on selected indicators of the MR (total lysine, reactive lysine, fructoselysine, ¿-N-carboxymethyllysine, (5-hydroxymethyl)-2-furfural, lysinoalanine), browning development and CIE-Lab color. Steam pelleting variables did not cause a significant loss of lysine or change in color and absorbance values. Analyzing the unprocessed ingredient mix suggests that the choice of the ingredients used in the ingredient mix, rather than the pelleting process applied, is responsible for the RL/TL ratio observed in the dry standard dog food used in this study. MRP content increased during steam pelleting (fructoselysine: 366.2 to 538.8 mg/kg DM; ¿-N-carboxymethyllysine: 12.6 to 14.8 mg/kg DM; lysinoalanine: 5.7 to 7.7 mg/kg DM; P <0.05). Increasing conditioning temperature from 65 to 90 °C increased fructoselysine (475.9 to 601.6 mg/kg DM; P <0.01) and ¿-N-carboxymethyllysine (14.3 to 15.1 mg/kg DM; P = 0.003). An increased die hole length of 80 mm decreased fructoselysine content compared to 45 and 65 mm (461.3 vs. 573.3 and 581.6 mg/kg DM; P <0.01) but increased lysinoalanine content (8.8 vs. 7.4 and 6.8 mg/kg DM; P = 0.002). Analyzing total and reactive lysine and absorbance values are not accurate enough to predict the MR and formation of MRPs during processing.
    Quantitation of Maillard reaction products in commercially available pet foods
    Rooijen, C. van; Bosch, G. ; Poel, A.F.B. van der; Wierenga, P.A. ; Alexander, L. ; Hendriks, W.H. - \ 2014
    Journal of Agricultural and Food Chemistry 62 (2014)35. - ISSN 0021-8561 - p. 8883 - 8891.
    performance liquid-chromatography - advanced glycation endproducts - infant milk formulas - nutritive-value - furfural compounds - canine diets - breast-milk - lysine - proteins - furosine
    During processing of pet food, the Maillard reaction occurs, which reduces the bioavailability of essential amino acids such as lysine and results in the formation of advanced Maillard reaction products (MRPs). The aim of this study was to quantitate MRPs (fructoselysine (FL), carboxymethyllysine (CML), hydroxymethylfurfural (HMF)) and the cross-link lysinoalanine (LAL) in commercial pet foods. Sixty-seven extruded, canned, and pelleted dog and cat foods for growth and maintenance were analyzed using UPLC-MS. Canned pet foods contained on average the most FL, CML, and HMF (4534, 37, and 1417 mg/kg dry matter, respectively) followed by pelleted and extruded foods. Average daily intake (mg/kg body weight0.75) of HMF is 122 times higher for dogs and 38 times higher for cats than average intake for adult humans. As commercial pet foods are most often the only source of food for dogs and cats, future research focus should be on the bioavailability and long-term health implications of MRP consumption by dogs and cats.
    Rumen degradation characteristics of ryegrass herbage and ryegrass silage are affected by interactions between stage of maturity and nitrogen fertilisation rate
    Heeren, J.A.H. ; Podesta, S.C. ; Hatew, B. ; Klop, G. ; Laar, H. van; Bannink, A. ; Warner, D. ; Jonge, L.H. de; Dijkstra, J. - \ 2014
    Animal Production Science 54 (2014)9. - ISSN 1836-0939 - p. 1263 - 1267.
    neutral detergent fiber - phleum-pratense l. - dairy-cows - nutritive-value - grass - timothy - protein - digestibility - emissions - matter
    The objective of this experiment was to evaluate interaction effects between stage of maturity and N fertilization rate on rumen degradation characteristics determined with nylon bag incubations of ryegrass herbages and ryegrass silage. Grass herbage (n = 4) was cut after 3 or 5 weeks of regrowth and received a low (20 kg N/ha) or a high (90 kg N/ha) fertilization rate. Grass silage (n = 6) received a low (65 kg N/ha) or high (150 kg N/ha) fertilization rate and was harvested at early (c 2000 kg DM/ha), mid (harvested 13 d later), or late (harvested 34 d later) maturity stage and ensiled in big bales. All grasses were incubated in the rumen of three lactating rumen-cannulated Holstein Friesian cows. Rumen degradation characteristics of organic matter (OM), nitrogen (N) and neutral detergent fibre (NDF) and the extent of effective degradation (ED) were evaluated. In grass herbage, NDF content varied between 390 and 454 g/kg DM and N content between 12.1 and 25.8 g/kg DM. In grass silage, NDF content varied between 438 and 593 g/kg DM and N content between 13.4 and 34.8 g/kg DM. In general, rumen degradation of grass herbage and grass silage decreased with increased maturity, and increased with increased fertilization rate. Significant interaction between maturity and fertilization rate was observed for ED of OM, N and NDF, except for ED of N in grass herbage. These results indicate that the effect of the rate of N fertilization on degradation of nutrients in the rumen of dairy cattle and on nutritional value depends on the grass maturity stage.
    Effects of processing technologies and pectolytic enzymes on degradability of nonstarch polysaccharides from rapeseed meal in broilers
    Vries, S. de; Pustjens, A.M. ; Kabel, M.A. ; Kwakkel, R.P. ; Gerrits, W.J.J. - \ 2014
    Poultry Science 93 (2014)3. - ISSN 0032-5791 - p. 589 - 598.
    dietary fiber components - canola-meal - metabolizable energy - nutritive-value - seeded canola - soybean-meal - poultry - digestibility - chickens - pigs
    Rapeseed meal (RSM) contains a high level of nonstarch polysaccharides (NSP) that are not well degraded in poultry and interfere with digestion of other nutrients as protein, starch, and fat. By altering physicochemical properties of NSP from RSM, processing and enzyme technologies might improve digestive utilization of RSM, enhancing its potential as a source of nutrients in poultry diets. The effects of wet milling and extrusion in combination with pectolytic enzymes on the degradability of RSM in broilers were investigated in a 3 × 2 factorial arrangement. Wet milling and extrusion did not affect total tract apparent digestibility of DM, CP, crude fat, and nonglucose polysaccharides (NGP). Addition of pectolytic enzymes did not affect total tract apparent digestibility of CP and crude fat, but improved degradability of NGP by 9 to 20% units (P <0.001), independent of prior technological processing of RSM. This coincided with an increased NGP concentration in the ceca (4 to 7 g/g of cobalt, P <0.001), indicating that more NGP were solubilized such that they could enter the ceca and become available for fermentation. Particle size reduction facilitated solubilization of polysaccharides from RSM, increasing the concentration of NGP found in the ceca (4 g/g of cobalt, P = 0.008). Without help of additional pectolytic enzymes, those solubilized structures could, however, still not be degraded by the cecal microbiota. Feed intake, BW gain, and feed conversion ratio were not affected. No interaction between processing technologies and enzyme addition was found. Apparently, the processing technologies studied were not facilitating accessibility of NSP to pectolytic enzymes added to the feed in vivo.
    In Situ Assessment of Ruminal Dry Matter Degradation Kinetics and Effective Rumen Degradability of Feedstuffs Originated from Agro-Industrial By-Products
    Habib, G. ; Ali, M. ; Bezabih, M. ; Khan, N.A. - \ 2013
    Pakistan Veterinary Journal 33 (2013)4. - ISSN 0253-8318 - p. 466 - 470.
    crude protein degradability - dairy-cows - nutritive-value - disappearance - silages - maize
    In the tropical Asian countries, information on nutrients availability from various by-products of agro-food industries remains scarce and even less is known about their application in the feed evaluation systems. The objective of this study was to generate renewed data on in situ rumen dry matter (DM) degradability of byproducts from oilseeds, cereal grains, and animal origin, commonly fed to animals in tropical Asian countries. The data were used to derive regression equations to understand the relationships between effective rumen degradability of DM (EDDM) and the rumen degradation characteristics of the by-products. Sixty four samples of five oilseed by-products, seven cereal grain by-products and four animal byproducts were used. From each feed, 4 samples (~1 kg each) were collected from dairy farms (n=1), local markets (n=1) and different agro-industries (n=2). The feeds were incubated in the rumen for 2, 4, 8, 12, 24 and 48 h, using nylon bag technique. There was a significant (P
    In situ ruminal crude protein degradability of by-products from cereals, oilseeds and animal origin
    Habib, G. ; Khan, N.A. ; Ali, M. ; Bezabih, M. - \ 2013
    Livestock Science 153 (2013)1-3. - ISSN 1871-1413 - p. 81 - 87.
    dry-matter - concentrate feedstuffs - nutritive-value - buffalo - cattle - rumen - digestibility - disappearance - passage - forage
    The aim of this study was to establish a database on in situ ruminal crude protein (CP) degradability characteristics of by-products from cereal grains, oilseeds and animal origin commonly fed to ruminants in Pakistan and South Asian Countries. The oilseed by-products were soybean meal, sunflower meal, mustard seed meal, cottonseed meal, decorticated and un-decorticated cottonseed cake, maize oil cake and mustard seed cake. The cereal grain by-products were corn gluten meal, corn gluten feed, guar meal, toria meal, rice meal, rice polishings, rice bran and wheat bran. The animal by-products were fish meal, feather meal, blood meal, and meat and bone meal. Four samples per feed were collected from different dairy farms (n=1), local markets (n=1), and agro-food industries (n=2). Ruminal protein degradation characteristics of the feeds were determined using the in situ nylon bag technique where each feed was incubated in the rumen of 3 mature steers for 2, 4, 8, 12, 24 and 48 h. There were large differences in instantly soluble (W) fraction, potentially rumen degradable (D) fraction, rate of degradation (kd) and effective degradability of crude protein (EDCP) among the by-product feeds. Among the oilseed by-products, mustard seed cake had the highest (P
    Gradients in fracture force and grazing resistance across canopy layers in seven tropical grass species
    Jacobs, A.A.A. ; Scheper, J.A. ; Benvenutti, M.A. ; Gordon, I.J. ; Poppi, D.P. ; Elgersma, A. - \ 2013
    Grass and Forage Science 68 (2013)2. - ISSN 0142-5242 - p. 278 - 287.
    foraging behavior - nutritive-value - cattle - sward - pastures - density - growth - steers - stems
    In reproductive swards, stems can act as a barrier that affects the grazing behaviour of ruminant livestock. The barrier effect of stems is closely associated with both the force required to fracture the stems and the density of these stems (in combination, these make up grazing resistance), and these factors need to be considered when making predictions about the forage intake of ruminants grazing reproductive pastures. Differences in grazing resistance between sward canopy layers of different grass species are thought to affect bite dimensions, but data are scarce. In this study, we assessed the grazing resistance for three canopy layers of seven tropical grass species. Species differed significantly in grazing resistance for every canopy layer, with a general ranking order for grazing resistance, in ascending order: Cenchrus ciliaris (‘American' buffel), Digitaria milanjiana (‘Jarra’ finger grass), Setaria surgens (annual pigeon grass), Setaria sphacelata (‘Narok’ setaria), Dichanthium sericeum (Queensland bluegrass), Chloris gayana (‘Callide’ Rhodes grass). In the top canopy layer, grazing resistance did not appear to create a barrier for any of the species, but in the bottom canopy layer, it did for all species. Species also differed in the relative contribution of fracture force and density to grazing resistance. The results highlight the importance of managing the grazing systems to minimize the barrier effect of the stems, which can be done by controlling the phenological stage of the pasture and the grass species and animal size used in the system.
    An economic assessment of drought effects on three grassland systems in Switzerland. Regional Environmental Change
    Finger, R. ; Gilgen, A. ; Prechsl, U. ; Buchmann, N. - \ 2013
    Regional Environmental Change 13 (2013)2. - ISSN 1436-3798 - p. 365 - 374.
    climate-change - land-use - temperate grasslands - nutritive-value - co2 enrichment - summer drought - white clover - europe - productivity - simulations
    This paper analyzes the economic impacts of summer drought on Swiss grassland production. We combine field trial data from drought experiments in three different grasslands in Switzerland with site-specific information on economic costs and benefits. The analysis focuses on the economic implications of drought effects on grassland yields as well as grassland composition. In agreement with earlier studies, we found rather heterogeneous yield effects of drought on Swiss grassland systems, with significantly reduced yields as a response to drought at the lowland and sub-alpine sites, but increased yields at the wetter pre-alpine site. Relative yield losses were highest at the sub-alpine site (with annual yield losses of up to 37 %). However, because income from grassland production at extensive sites relies to a large extent on ecological direct payments, even large yield losses had only limited implications in terms of relative profit reductions. In contrast, negative drought impacts at the most productive, intensively managed lowland site were dominant, with average annual drought-induced profit margin reductions of about 28 %. This is furthermore emphasized if analyzing the farm level perspective of drought impacts. Combining site-specific effects at the farm level, we found that in particular farms with high shares of lowland grassland sites suffer from summer droughts in terms of farm-level fodder production and profit margins. Moreover, our results showed that the higher competitiveness of weeds (broad-leaved dock) under drought conditions will require increasing attention on weed control measures in future grassland production systems. Taking into account that the risk of drought occurrence is expected to increase in the coming years, additional instruments to cope with drought risks in fodder production and finally farmers’ income have to be developed.
    Improving digestive utilization of fiber-rich feedstuffs in pigs and poultry by processing and enzyme technologies: A review
    Vries, S. de; Pustjens, A.M. ; Schols, H.A. ; Hendriks, W.H. ; Gerrits, W.J.J. - \ 2012
    Animal Feed Science and Technology 178 (2012)3-4. - ISSN 0377-8401 - p. 123 - 138.
    cereal nonstarch polysaccharides - early-weaned piglets - chain fatty-acids - plant-cell walls - broiler-chickens - dietary fiber - nutritive-value - particle-size - gastrointestinal-tract - extrusion-cooking
    The effects of processing technologies, whether or not combined with cell wall degrading enzymes, on the physicochemical properties of non-starch polysaccharides (NSP) and the resulting effects on NSP degradation in both pigs and poultry were reviewed. Evaluation of the effects of processing technologies on digestion of NSP is hampered by the potential shift of polysaccharides recovered in the fiber fractions of common, gravimetric, fiber analysis methods. Results from in vivo studies describing effects of processing technologies or enzyme treatments on crude fiber, neutral detergent fiber, or acid detergent fiber digestibility, instead of NSP digestibility, should therefore, be interpreted with care. Detailed information on the composition of the NSP-fraction and digestibility of its components will help to identify and understand modifications that occur during processing. Processes based on mechanical modification of feedstuffs that are commonly used in the feed industry, such as hammer and roller milling increase solubility of the NSP-fraction resulting in a 6–7 percentage unit increase in coefficient of apparent total tract digestibility (CATTD) of the fiber fraction in both pigs and poultry. Dry thermal processes have a minor impact on physicochemical properties of feedstuffs and consequently, the effects on the coefficient of apparent ileal digestibility (CAID) and CATTD of the fiber fractions in pigs and poultry are limited. Hydrothermal processes that include high shear forces such as expander processing and extrusion cooking are more effective and increase solubility but also viscosity. The CATTD of fiber fractions in pigs can be increased on average 3 percentage units by hydrothermal processing of feeds and feed ingredients, although some studies have reported unchanged or even decreased digestibility values. In poultry, CATTD of fiber fractions can be increased 4–16 percentage units by hydrothermal processing. Increased digesta viscosity resulting from technological processing of feed and feed ingredients can be counteracted by the addition of specific enzymes. Enzyme addition to heat processed diets and diets containing heat processed ingredients results in a 3- to 4-fold reduction in viscosity compared with enzyme addition to unprocessed diets, or diets containing unprocessed ingredients. In addition, modifications in cell wall architecture obtained by processing technologies will improve the accessibility of NSP to enzymes. As a result, the effects of enzyme addition on digestibility of the fiber fraction are 1.5–6 times larger, when applied to heat processed diets compared with unprocessed diets.
    Inclusion of ensiled cassava KM94 leaves in diets for growing pigs in Vietnam reduces growth rate but increases profitability
    Nguyen, T.H.L. ; Ngoan, L.D. ; Verstegen, M.W.A. ; Hendriks, W.H. - \ 2011
    Asian-Australasian Journal of Animal Sciences 24 (2011)8. - ISSN 1011-2367 - p. 1157 - 1163.
    total tract digestibility - carcass characteristics - nutritive-value - amino-acids - fish-meal - root meal - products - cyanogens - protein
    This study was conducted to determine the effect of the inclusion of different levels of ensiled cassava leaves (variety KM94) in the diets on performance and carcass characteristics of growing pigs in Vietnam. A total of 40 crossbreds pigs (Large White${\times}$Mong Cai, 20 males and 20 females) with an initial live weight of 23.5 kg (SD = 0.86) were randomly allocated to one of the four pens across 5 units. Four experimental diets were formulated for two growth periods, period 1 (60 days) for 20 to 50 kg and period 2 lasted 30 days, from 50 kg until slaughter. Four diets were formulated containing inclusion levels of ensiled cassava KM94 leaves diet of 0, 10, 15 and 20% in the DM. Diets were formulated based on previously determined ileal amino acid digestibility values of the KM94 products and were isonitrogenous and isocaloric on a metabolizable energy basis. Each pen of pigs was randomly assigned to one of the four dietary treatments. Dry matter intake and final weight tended to decreased with increasing levels of ensiled cassava KM94 leaves in the diet while there was a significant (p = 0.022) decrease in average daily gain. Protein depositions of the F1 pigs tended (p = 0.093) to decrease with increasing inclusion levels of ensiled cassava KM94 leaves. There was no significant difference in feed conversion ratio, carcass quality and fat gain between the groups of pigs. There were clear differences in feed costs among the experimental diets (p = 0.001) with increasing levels of ensiled cassava KM 94 leaves in the diet reducing feed costs. It was concluded that, in diets for growing pig, inclusion of ensiled cassava leaves reduces growth rate of pigs in Vietnam but increases profitability as measured by feed costs
    Effects of xylanase and citric acid on the performance, nutrient retention, and characteristics of gastrointestinal tract of broilers fed low-phosphorus wheat-based diets
    Esmaeilipour, O. ; Shivazad, M. ; Moravej, H. ; Aminzadeh, S. ; Rezaian, M. ; Krimpen, M.M. van - \ 2011
    Poultry Science 90 (2011)9. - ISSN 0032-5791 - p. 1975 - 1982.
    polysaccharide-hydrolyzing enzymes - growth-performance - digestive-tract - intestinal viscosity - microbial phytase - blood parameters - nutritive-value - gut microflora - young chicks - digestibility
    An experiment was conducted to study the effects of xylanase and citric acid on the performance, nutrient retention, jejunal viscosity, and size and pH of the gastrointestinal tract of broilers fed a low-P wheat-based diet. The experiment was conducted as a 2 × 3 factorial arrangement with 2 levels of xylanase (0 and 200 mg/kg) and 3 levels of citric acid (0, 20, and 40 g/kg). Each of the 6 dietary treatments was fed to 4 replicate pens (17 birds/pen) from 0 to 24 d of age. Chromium oxide (3 g/kg) was added to the diets as an indigestible marker to determine the apparent nutrient retention. No interaction effect was observed between xylanase and citric acid in any measured response. Xylanase did not affect feed intake but significantly increased BW gain by 3.6% (P <0.05) from 1 to 24 d of age and improved G:F by 3.9% (P <0.01). The inclusion of 40 g/kg of citric acid decreased (P <0.01) BW gain and feed intake by 8.6 and 12.5%, respectively. The inclusion of 20 and 40 g/kg of citric acid improved G:F by 2.3 and 4.5% (P <0.05), respectively. Xylanase significantly decreased the viscosity of digesta and improved the retention of DM, CP, and energy, but did not have a significant effect on the retention of fat and P. Inclusion of 20 and 40 g/kg of citric acid in the diets increased P retention by 15.8 and 16.3% (P <0.01), respectively. Citric acid significantly decreased the pH of crop contents (P <0.05). In conclusion, citric acid, at the 40 g/kg inclusion level, reduced feed intake and BW gain but improved G:F and P retention. Xylanase decreased digesta viscosity, increased nutrient retention, and consequently improved the performance of broilers fed the low-P wheat-based diet. Thus, adding 20 g/kg of citric acid, especially in the starter period, and 200 mg/kg of xylanase to low-P wheat-based diets can be helpful
    Modelling above-ground herbage mass for a wide range of grassland community types
    Duru, M. ; Adam, M.Y.O. ; Cruz, P. ; Martin, G. ; Ansquer, P. ; Ducourtieux, C. ; Jouany, C. ; Theau, J.P. ; Viegas, J. - \ 2009
    Ecological Modelling 220 (2009)2. - ISSN 0304-3800 - p. 209 - 225.
    permanent pastures - tall fescue - photosynthetic capacity - botanical composition - farming systems - growth analysis - nutritive-value - plant traits - leaf traits - nitrogen
    Whereas it is recognized that management of plant diversity can be the key to reconciling production and environmental aims, most grassland models are tailored for high-value grass species. We proposed to adapt a mono-specific grass model to take into account specific features of species-rich permanent grasslands, especially over the reproductive phase. To this end, we used the concept of plant functional type (PFT), i.e. the grouping of plant species according to plant traits determined by the response of plant species to different management practices (land use and fertilization) and characterizing of agronomic properties of the corresponding species. In the model, weather and nutrient availability act upon rates of biophysical processes (radiation capture and use, plant senescence). These rates are modified over times due to PFT-specific parameters determined experimentally which represent the different strategies of plant species regarding growth. The integration of these parameters into the model made it possible to predict herbage biomass accumulation rate under different management practices for a wide range of plant communities differing in their PFT composition. The model was evaluated in two steps, first by analyzing separately the effects of PFT and an indicator of nutrient availability on herbage accumulation and then by conducting a sensitivity analysis. It was validated using two independent datasets; a cutting experiment running over the whole growing season to examine the consistency of the model outputs under different cutting regimes, and a monitoring of meadows and pastures in spring over a whole growth cycle to assess the model’s ability to reproduce growth curves. Although a good fit was observed between the simulated and observed data, the few discrepancies noticed between field data and predicted values were attributed mainly to the potential presence of non-grass species. More specifically, we noticed that nutrient (mainly nitrogen) availability is the main driver of plant growth rate, and that PFT determines the times at which this rate changes in relation to the phenological characteristics of species present. We concluded that integration of the PFT concept into the initial mono-specific growth model is especially suited to evaluating the consequences of management practices on species-rich permanent grasslands to meet feed production targets
    Effects of forage maize type and maturity stage on in vitro rumen fermentation characteristics.
    Cone, J.W. ; Gelder, A.H. van; Schooten, H.A. van - \ 2008
    NJAS Wageningen Journal of Life Sciences 55 (2008). - ISSN 1573-5214 - p. 139 - 154.
    pensbacteriën - pens - spijsvertering - voederconversievermogen - veevoeder - maïskuilvoer - maïs - rassen (planten) - verteerbaarheid - rumen bacteria - rumen - digestion - feed conversion efficiency - fodder - maize silage - maize - varieties - digestibility - gas-production - ensiling characteristics - nutritive-value - carbohydrate fractions - starch degradation - harvest date - kinetics - europe - yield
    An experiment with forage maize plants representing early and late-ripening types of Dry Down and Stay Green cultivar types was conducted to study the effects of cultivar and maturity stage on in vitro rumen fermentation characteristics and to investigate the validity of the generally supposed qualities of these cultivars. Plants were harvested at an estimated whole plant dry matter (DM) content of 250, 320 or 390 g kg¿1, on 20 August, 16 September and 3 October 2003, respectively. Chemical composition and in vitro rumen fermentation characteristics, using the gas production technique, were determined of samples from entire not ensiled plants, ears and stover and from entire plants after ensiling. The increase in whole plant DM content from 250 to 320 g kg%sup-1; (20 August - 16 September) caused starch content of the whole plants to increase and neutral detergent fibre (NDF) digestibility to decrease, both more than prolonged ripening (to 390 g DM kg-1). DM content at harvest had a statistically significant influence on degree and rate of in vitro rumen fermentation. Calculated in vitro starch degradation after 10 h of incubation in rumen fluid suggested an increased content of rumen escape starch in the older samples. Maize type had only minor effects on fermentation characteristics, which were most pronounced for the ears and the remaining stover. Although the observed differences caused by the Dry Down or Stay Green characteristics were statistically significant in some cases, they were not systematic not for the early nor for the late-ripening types.
    Chemical composition of lamina and sheath of Lolium perenne as affected by herbage management
    Hoekstra, N.J. ; Struik, P.C. ; Lantinga, E.A. ; Schulte, R.P.O. - \ 2007
    NJAS Wageningen Journal of Life Sciences 55 (2007)1. - ISSN 1573-5214 - p. 55 - 73.
    afsnijhoogte - grasbestand - voedergewassen - lolium perenne - hergroei - rotaties - chemische samenstelling - graslandbeheer - voedingswaarde - lignine - totale hoeveelheid droge stof - koolhydraten - stikstof - vezelgehalte - bloeiwijzen - cutting height - herbage - fodder crops - lolium perenne - regrowth - rotations - chemical composition - grassland management - nutritive value - lignin - total solids - carbohydrates - nitrogen - fibre content - inflorescences - water-soluble carbohydrate - neutral detergent fiber - dairy-cows - nitrogen application - nutritive-value - ryegrass varieties - animal nutrition - milk-production - rumen function - l. cultivars
    The quality of grass in terms of form and relative amounts of energy and protein affects both animal production per unit of intake and nitrogen (N) utilization. Quality can be manipulated by herbage management and choice of cultivar. The effects of N application rate (0, 90 or 390 kg N ha¿1 year¿1), duration of regrowth period (2¿3, 4¿5, or 6¿7 weeks), and cutting height (8 or 12 cm) on the mass fractions of nitrogen (N), water-soluble carbohydrates (WSC), neutral detergent fibre (NDF), acid detergent fibre (ADF), lignin and ash in lamina and sheath material of a high-sugar (Aberdart) and a low-sugar (Respect) perennial ryegrass (Lolium perenne) cultivar, were studied in a factorial field experiment during four seasons in 2002 and 2003. Expressing NDF and ADF mass fractions in g per kg WSC-free dry matter (DM) increased the consistency of treatment effects. The high-sugar cultivar had generally higher WSC mass fractions than the low-sugar cultivar, especially during the late season. Moreover, the relative difference in WSC mass fraction between the two cultivars tended to be higher for the lamina material than for the sheath material, which suggests that the high-sugar trait may be more important under grazing conditions, when lamina forms the bulk of the intake, than under mowing regimes. Longer regrowth periods and lower N application rates increased WSC mass fractions and decreased N mass fractions; interactions between regrowth period and N application rate were highly significant. The mass fractions of NDF and ADF were much less influenced. The NDF mass fraction in terms of g per kg WSC-free DM tended to be higher at lower N application rates and at longer regrowth periods. The effect of cutting height on herbage chemical composition was unclear. In conclusion, high-sugar cultivars, N application rate and length of the regrowth period are important tools for manipulating herbage quality.
    Effects of perennial ryegrass cultivars on milk yield and nitrogen utilization in grazing dairy cows
    Tas, B.M. ; Taweel, H.Z. ; Smit, H.J. ; Elgersma, A. ; Dijkstra, J. ; Tamminga, S. - \ 2006
    Journal of Dairy Science 89 (2006). - ISSN 0022-0302 - p. 3494 - 3500.
    water-soluble carbohydrate - lolium-perenne - herbage intake - nutritive-value - l. cultivars - performance - metabolism - lactation - pasture - quality
    The effects of 4 diploid perennial ryegrass cultivars that differed in water-soluble carbohydrate (WSC) concentrations on milk yield and nitrogen (N) utilization in dairy cows were evaluated in a 2-yr grazing experiment. Twelve lactating dairy cows were assigned to 1 cultivar for a 2-wk period in a 4 x 4 Latin square design with 3 replicates. Each year, the experiment lasted 8 wk. Swards were in a vegetative stage throughout the experiment. Herbage constituents were determined, and DM intake was estimated with the n-alkane technique. Nitrogen utilization was calculated as N excreted in milk divided by N intake, assuming a zero N retention. Two cultivars had consistently higher WSC concentrations and slightly lower neutral detergent fiber concentrations than the other 2 cultivars. The ranking of the cultivars in chemical composition traits in both years was rather consistent. Cows grazing the cultivar with the lowest concentration of WSC had the lowest herbage DM intake, N intake, milk yield, and milk N yield in 2002, but with a similar difference in WSC concentration, no differences among cultivars were found in 2003. In both years, milk urea N concentration was slightly higher for cows grazing the cultivar with the lowest WSC concentration, although it was significant only in 2003. Nitrogen utilization (N milk:N intake, g/g) varied between 0.241 and 0.246 in 2002 and between 0.190 and 0.209 in 2003, and in both years there was no effect of cultivar. At relatively high N concentrations in grass and only small differences among cultivars in neutral detergent fiber concentrations, cultivars with an elevated WSC concentration did not increase N utilization in grazing dairy cows
    Dairy cattle grazing preference among six cultivars of perennial ryegrass
    Smit, H.J. ; Tamminga, S. ; Elgersma, A. - \ 2006
    Agronomy Journal 98 (2006)5. - ISSN 0002-1962 - p. 1213 - 1220.
    tall fescue cultivars - diet selection - animal preference - nutritive-value - herbage intake - cows - sheep - choice - l. - palatability
    Received for publication September 13, 2005. Six endophyte-free diploid perennial ryegrass (Lolium perenne L.) cultivars (Abergold, Respect, Agri, Herbie, Barezane, and Barnhem) were examined in an experiment to investigate the selection behavior of grazing Holstein Friesian cows in July and September 2003 and May 2004 and to identify factors related to preference. Three groups of dairy cows (Bos taurus) were allowed to select among these six cultivars that were sown in replicates in a randomized block design with 12 plots (36.7 by 2.0 m). Each experiment lasted 4 d, and every day cows were offered a new field with 12 plots. Herbage intake was measured using the sward-cutting method, measuring herbage yield before and after grazing. The Chesson¿Manly index was used to quantify cattle grazing preference. Dairy cows did select among the cultivars in every period. The pattern of selection was consistent over the three experiments, Abergold was selected most, and Agri and Respect were least selected (22 vs. 14%). In July 2003 and May 2004, cultivars differed in morphological characteristics, but this was not related with grazing preference. In all three experiments, distinct differences were found among cultivars in chemical composition [dry matter (DM), ash, neutral detergent fiber, and water soluble carbohydrates (WSC) concentration] and digestibility of organic matter, especially for WSC concentration, which, when averaged over experiments, ranged between 135 g kg¿1 DM (Barezane) and 165 g kg¿1 DM (Abergold). Dairy cows preferred the cultivars with low ash and fiber concentration and high WSC concentration and digestibility
    Simulation of milk production by dairy cows fed sugarcane top-based diets with locally available supplements under Indian condition
    Behera, U.K. ; Kebreab, E. ; Dijkstra, J. ; Assis, A.G. ; France, J. - \ 2005
    The Journal of Agricultural Science 143 (2005)2-3. - ISSN 0021-8596 - p. 217 - 229.
    cattle fed sugarcane - nutritive-value - crude protein - digestion - insitu - rumen - model - urea
    A model of sugarcane digestion was applied to indicate the suitability of various locally available supplements for enhancing milk production of Indian crossbred dairy cattle. Milk production was calculated according to simulated energy, lipogenic, glucogenic and aminogenic substrate availability. The model identified the most limiting substrate for milk production from different sugarcane-based diets. For sugarcane tops/urea fed alone, milk production was most limited by amino acid followed by long chain fatty acid availability. Among the protein-rich oil cake supplements at 100, 200 and 300 g supplement/kg total DM, cottonseed oil cake proved superior with a milk yield of 5·5, 7·3 and 8·3 kg/day, respectively. This was followed by mustard oil cake with 5·1, 6·5 and 7·6 kg/day, respectively. In the case of a protein-rich supplement (fish meal), milk yield was limited to 6·6 kg/day due to a shortage of long chain fatty acids. However, at 300 g of supplementation, energy became limiting, with a milk yield of 6·7 kg/day. Supplementation with rice bran and rice polishings at 100, 200 and 300 g restricted milk yield to 4·3, 4·9 and 5·5 and 4·5, 5·3 and 6·1 kg/day, respectively, and amino acids became the factor limiting milk production. The diet comprising basal sugarcane tops supplemented by leguminous fodder, dry fodder (e.g. rice or wheat straw) and concentrates at levels of 100, 200 and 300 g supplements/kg total diet DM proved to be the most balanced with a milk yield of 5·1, 6·7 and 9·0 kg/day, respectively
    In vitro degradation characteristics of timothy and red clover at different harvest times
    Hetta, M. ; Gustavsson, A.M. ; Cone, J.W. ; Martinsson, K. - \ 2004
    Acta Agriculturae Scandinavica Section A-Animal Science 54 (2004)1. - ISSN 0906-4702 - p. 20 - 29.
    gas-production - chemical-composition - nutritive-value - primary growth - cutting time - white clover - plant-parts - digestibility - fermentation - kinetics
    The nutritional value of red clover (Trifolium pratense L.) and timothy (Phleum pratense L.) were studied over two consecutive growing seasons (1995 and 1996) with an in vitro gas production technique and chemical analysis. The decline in degradability was more pronounced with increasing maturity in timothy than in red clover during spring growth, but similar during summer growth. Red clover contained more components soluble in neutral detergent solution (NDS) at all harvest occasions. The fractional degradation rate for the NDS fraction was lower in red clover compared to timothy. Red clover had slightly higher fractional degradation rate for the whole forage, but the total kinetic release of energy was similar for the two species at the same harvest time. The results indicate that timothy and red clover have different intrinsic characteristics limiting degradation. Effects of the treatments with NDS on the allocation of pectins could partially explain the differences in degradation characteristics
    Towards Sustainable Production of Protein-Rich Foods: Appraisal of Eight Crops for Western Europe. Part II: Analysis of the Technological Aspects of the Production Chain
    Swaving Dijkstra, D. ; Linnemann, A.R. ; Boekel, M.A.J.S. van - \ 2003
    Critical Reviews in Food Science and Nutrition 43 (2003)5. - ISSN 1040-8398 - p. 481 - 506.
    white leaf protein - sodium hexametaphosphate extraction - ammonia-water-treatment - pilot-plant production - rapeseed protein - functional-properties - nutritive-value - toxicological evaluation - chemical-composition - diffusion-extraction
    Increased production of plant protein is required to support the production of protein-rich foods which can replace meat in the human diet to reduce the strain that intensive animal husbandry poses on the environment. The suitability of lupin (Lupinus spp.), pea (Pisum sativum), quinoa (Chenopodium quinoa Willd.), triticale (x Triticosecale), lucerne (Medicago sativa), grasses (Lolium and Festuca spp.), rapeseed/canola (Brassica napus) and potato (Solanum tuberosum) for protein production in Western Europe was studied on the basis of a chain-approach. The technological aspects, which are considered in this paper, are the processing methods, and the functional and nutritional properties of the derived protein products. The overall evaluation of the technological prospects of the eight crops as a protein source for Western Europe leads to the conclusion that this part of the production chain is not decisive for that choice. Pea and lupin have a slight advantage over the other crops, because their concentrates and isolates are already commercially available.
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