Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

    Current refinement(s):

    Records 1 - 11 / 11

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    Estimation of residual energy intake and its genetic background during the growing period in pigs
    Shirali, M. ; Doeschl-Wilson, A. ; Duthie, C. ; Knap, P.W. ; Kanis, E. ; Arendonk, J.A.M. van; Roehe, R. - \ 2014
    Livestock Science 168 (2014). - ISSN 1871-1413 - p. 17 - 25.
    feed-intake - production traits - body-composition - nitrogen-excretion - chemical-analysis - yorkshire swine - growth - parameters - association - efficiency
    The aims of this study were to (i) compare models estimating residual energy intake (REI) using either lean and fat tissue growth or their proxy traits (average daily gain (ADG) and backfat thickness (BF)); (ii) determine genetic characteristics of REI at different growth stages and the entire test period; and (iii) examine 9 genetic and phenotypic relationships of REI with other production traits. Data from 315 pigs of an F2 generation were used which originated from crossing Pietrain sires with a commercial crossbred dam population. Average daily protein (APD) and lipid deposition (ALD), as measurements of lean and fat tissue growth, were obtained using the deuterium dilution technique on live animals. During growth from 60 to 140 kg, REI was estimated using 4 different models for energy intake that included, besides other systematic effects, (1) ADG and BF; (2) APD and ALD; (3) and (4) incorporated the same covariables as the first two models, respectively, but pre-adjusted for systematic effects. Genetic parameters and estimated breeding values were obtained based on univariate animal models using REML analysis. Over the entire growing period, heritabilities of different REI using different models were all estimated at 0.44 and their genetic correlations were at unity. At different growth stages heritabilities for REI were greater ranging from 0.47 to 0.50. Genetic correlations between REI estimates at different stages of growth, obtained using genetic model 4, indicated that REI at 60 to 90 kg was non-significantly (P>0.05) associated with REI at 90–120 kg (0.32±0.29) and 120–140 kg (0.28±0.28), but REI of the latter growth stages showed a significant (P
    Interaction between dietary content of protein and sodium chloride on milk urea concentration, urinary urea excretion, renal recycling of urea, and urea transfer to the gastrointestinal tract in dairy cows
    Spek, J.W. ; Bannink, A. ; Gort, G. ; Hendriks, W.H. ; Dijkstra, J. - \ 2013
    Journal of Dairy Science 96 (2013)9. - ISSN 0022-0302 - p. 5734 - 5745.
    fed grass-silage - ammonia emissions - nitrogen-excretion - holstein cows - cattle - metabolism - sheep - rumen - plasma - degradability
    Dietary protein and salt affect the concentration of milk urea nitrogen (MUN; mg of N/dL) and the relationship between MUN and excretion of urea nitrogen in urine (UUN; g of N/d) of dairy cattle. The aim of the present study was to examine the effects of dietary protein and sodium chloride (NaCl) intake separately, and their interaction, on MUN and UUN, on the relationship between UUN and MUN, on renal recycling of urea, and on urea transfer to the gastrointestinal tract. Twelve second-parity cows (body weight of 645±37kg, 146±29d in milk, and a milk production of 34.0±3.28kg/d), of which 8 were previously fitted with a rumen cannula, were fitted with catheters in the urine bladder and jugular vein. The experiment had a split-plot arrangement with dietary crude protein (CP) content as the main plot factor [116 and 154g of CP/kg of dry matter (DM)] and dietary NaCl content as the subplot factor (3.1 and 13.5g of Na/kg of DM). Cows were fed at 95% of the average ad libitum feed intake of cows receiving the low protein diets. Average MUN and UUN were, respectively, 3.90mg of N/dL and 45g of N/d higher for the high protein diets compared with the low protein diets. Compared with the low NaCl diets, MUN was, on average, 1.74mg of N/dL lower for the high NaCl diets, whereas UUN was unaffected. We found no interaction between dietary content of protein and NaCl on performance characteristics or on MUN, UUN, urine production, and renal clearance characteristics. The creatinine clearance rate was not affected by dietary content of protein and NaCl. Urea transfer to the gastrointestinal tract, expressed as a fraction of plasma urea entry rate, was negatively related to dietary protein, whereas it was not affected by dietary NaCl content. We found no interaction between dietary protein and NaCl content on plasma urea entry rate and gastrointestinal urea entry rate or their ratio. The relationship between MUN and UUN was significantly affected by the class variable dietary NaCl content: UUN=-17.7±7.24 + 10.09±1.016 × MUN + 2.26±0.729 × MUN (for high NaCl); R(2)=0.85. Removal of the MUN × NaCl interaction term lowered the coefficient of determination from 0.85 to 0.77. In conclusion, dietary protein content is positively related to MUN and UUN, whereas dietary NaCl content is negatively correlated to MUN but NaCl content is not related to UUN. We found no interaction between dietary protein and NaCl content on performance, MUN, UUN, or renal urea recycling, nor on plasma urea entry rate and urea transfer to the gastrointestinal tract. For a proper interpretation of the relationship between MUN and UUN, the effect of dietary NaCl should be taken into account, but we found no evidence that the effect of dietary NaCl on MUN is dependent on dietary protein content.
    A review of factors influencing milk urea concentration and its relationship with urinary urea excretion in lactating dairy cattle
    Spek, J.W. ; Dijkstra, J. ; Duinkerken, G. van; Bannink, A. - \ 2013
    The Journal of Agricultural Science 151 (2013)3. - ISSN 0021-8596 - p. 407 - 423.
    oscillating dietary-protein - bovine ruminal epithelium - medullary collecting duct - dry-matter digestibility - sheep rumen epithelium - nitrogen-excretion - sodium-chloride - nutrient digestibility - short communication - genetic-parameters
    Milk urea nitrogen (MUN) concentration in dairy cows may serve as an on-farm indicator to guide nutritional strategies and to help reduce emissions of nitrogen (N) to the environment. Excretion of urinary urea nitrogen (UUN) is positively related to MUN, but the relationship is highly variable. The accuracy of MUN as a predictor of UUN may improve when various factors that affect this relationship can be taken into account. The current review discusses the impact of a number of UUN : MUN ratio influencing factors related to: physiological mechanisms in the dairy cow, farm management, differences between individual cows, nutrition and analysis methods for MUN. Factors related to variation in water intake, urine production, dietary protein level, body weight (BW) and time and frequency of feeding and milking are shown to affect MUN and its relationship with UUN. In addition, a number of factors are discussed that are likely to affect this relationship such as biological rhythm, renal reabsorption of urea during periods of protein deficiency and breeding value for MUN. Accounting for these above-mentioned factors in the relationship between MUN and UUN might substantially improve the applicability and accuracy of MUN as a predictor of protein utilization efficiency and UUN.
    Effect of sodium chloride intake on urine volume, urinary urea excretion, and milk urea concentration in lactating dairy cattle
    Spek, J.W. ; Bannink, A. ; Gort, G. ; Hendriks, W.H. ; Dijkstra, J. - \ 2012
    Journal of Dairy Science 95 (2012)12. - ISSN 0022-0302 - p. 7288 - 7298.
    nitrogen-excretion - ammonia emissions - water restriction - renal-function - cows - sheep - metabolism - protein - agriculture - potassium
    Milk urea nitrogen (MUN; mg of N/dL) has been shown to be related to excretion of urinary urea N (UUN; g of N/d) and total excretion of urinary N (UN; g of N/d) in dairy cows. In the present experiment, it was hypothesized that MUN and the relationship between MUN and UUN or UN is affected by urine volume as a result of dietary sodium chloride intake. Twelve lactating Holstein-Friesian dairy cows (mean ± SD: milk production 28.1 ± 3.23 kg/d and 190 ± 41 d in milk), of which 4 were fitted with catheters in the urine bladder and jugular vein, were randomly assigned to 4 dietary levels of sodium chloride (3, 9, 14, and 19 g of Na/kg of DM) according to a triple 4 × 4 Latin square design. Cows were fed at 95% of ad libitum intake, excluding salt addition. Milk was analyzed for MUN and protein content; urine was analyzed for total N, urea, and creatinine content; feces were analyzed for total N and DM content; and blood plasma was analyzed for urea and creatinine content. Creatinine clearance rate (CCR; L/min) and renal urea reabsorption ratio were estimated based on plasma concentrations of urea and creatinine, and total excretion of urea and creatinine in urine. Intake of DM and N, milk production, and milk protein content were (mean ± SD), on average, 21.4 ± 1.24 kg/d, 522 ± 32.0 g/d, 25.4 ± 2.53 kg/d, and 3.64 ± 0.186%, respectively. A linear relationship was found between Na intake and urine production [urine (kg/d; mean ± SE) = 7.5 ± 4.33 + 0.136 ± 0.0143 × Na intake (g/d)] and between Na intake and MUN [MUN (mg/dL; mean ± SE) = 13.5 ± 0.35 - 0.0068 ± 0.00104 × Na intake (g/d)]. Despite the decrease in MUN with increased Na intake, UN excretion increased linearly with Na intake. Excretion of UUN was not affected by dietary Na content. A linear plateau relationship was observed between CCR and renal urea reabsorption. An increase in CCR coincided with an increase in calculated renal urea reabsorption until a CCR breakpoint value (mean ± SD) of 1.56 ± 0.063 L/min was reached. We conclude that Na intake is negatively related to MUN, whereas UUN is not affected. Variation in mineral intake levels that affect urine volume should, therefore, be taken into account when using MUN as an indicator of UUN in dairy cattle.
    Milk urea concentration as an indicator of ammonia emission from dairy cow barn under restricted grazing
    Duinkerken, G. van; Smits, M.C.J. ; Andre, G. ; Sebek, L.B.J. ; Dijkstra, J. - \ 2011
    Journal of Dairy Science 94 (2011)1. - ISSN 0022-0302 - p. 321 - 335.
    livestock buildings - nitrogen-excretion - dietary nitrogen - ventilation rate - manure stores - protein - cattle - model - volatilization - houses
    Bulk milk urea concentration was evaluated to assess its potential as an indicator of ammonia emission from a dairy cow barn in a situation with restricted grazing. An experiment was carried out with a herd of, on average, 52 Holstein-Friesian dairy cows. The cows were housed in a naturally ventilated barn with cubicles and a slatted floor, were fed ensiled forages and feed supplements, and each day were allowed 8.5 h of grazing. The experiment was a balanced randomized block design, replicated 3 times. The experimental factor was the bulk milk urea level, which was adjusted to levels of 15, 35, and 55 mg of urea per 100 g of milk, respectively, by changing the level of nitrogen fertilization of the pasture, the herbage mass and grass regrowth age, and the level and type of feed supplement. Ammonia emission from the barn was measured using sulfur hexafluoride as the tracer gas. Ammonia emission generally increased upon an increase in adjusted milk urea levels. A dynamic regression model was used to predict ammonia emission from bulk milk urea concentration, temperature, and a slurry mixing index. This model accounted for 66% of the total variance in ammonia emission and showed that emission increases exponentially with increasing milk urea concentration. At levels of 20 and 30 mg of urea per 100 g of milk, ammonia emission increased by about 2.5 and 3.5%, respectively, when milk urea concentration increased by 1 mg/100 g. Furthermore, emissions from the barn increased 2.6% when temperature increased by 1°C. The study showed that bulk milk urea concentration is a useful indicator for ammonia emissions from a dairy cow barn in a situation with restricted grazing.
    Odour and ammonia emission from pig manure as affected by dietary crude protein level
    Le, P.D. ; Aarnink, A.J.A. ; Jongbloed, A.W. - \ 2009
    Livestock Science 121 (2009)2-3. - ISSN 1871-1413 - p. 267 - 274.
    growing-finishing pigs - nitrogen-excretion - swine manure - slurry - acids
    The objective of this study was to determine the effects of dietary crude protein (CP) level on odour emission, odour intensity, odour hedonic tone, ammonia and greenhouse gaseous emission from pig manure, and on fresh faeces and manure characteristics. An experiment was conducted with finishing pigs (n = 12) in a randomized complete block arrangement with 2 treatments of 12 and 15% dietary CP in six blocks. The 2 diets were supplemented with essential AA up to the level of the animal's requirement. Pigs with an initial body weight (BW) of 57.7 ± 0.7 kg were penned individually in partly slatted floor pens. Faeces and urine of each pig accumulated in separate manure pits under the slatted floor. In the 3rd week of the collection period, fresh faeces were collected for identifying fresh faeces characteristics and for assessing dry matter, organic matter, nitrogen (N), fat and non-starch polysaccharides digestibility using Cr2O3 as a marker. In the 6th week of the collection period, air samples were collected directly from each manure pit: one for odour, one for ammonia concentration and one for greenhouse gases. Afterwards the manure was mixed and a representative sample was taken for manure characteristic analysis. Odour samples were analyzed for odour concentration and for hedonic tone and odour intensity. Manure samples were analyzed for volatile fatty acids (VFA), indolic, phenolic, sulphurous compounds, ammonium and total N concentrations and pH. Reducing dietary CP level from 15 to 12% did not affect odour emission, odour intensity and odour hedonic tone and greenhouse gaseous concentration (CH4, CO2 and N2O) (P > 0.05) of odorous air above the manure pit. Reduced dietary CP level decreased manure pH (P <0.001), total N (P <0.001) and ammonium (P <0.001) concentrations and ammonia emission from pig manure (P = 0.03). In addition, total VFA, acetic, propionic, iso-butanoic and iso-pentanoic acids, phenol, 4-ethyl phenol and carbon disulfide concentrations in manure were decreased by reducing dietary CP level (P <0.05). We conclude that reducing dietary CP from 15 to 12% did not reduce odour emission and greenhouse gaseous concentration; however, ammonia emission was significantly reduced.
    Effects of chronic and periodic exposure to ammonia on growth and blood physiology in juvenile turbot (Scophthalmus maximus)
    Foss, A. ; Imsland, A.K. ; Roth, B. ; Schram, E. ; Stefansson, S.O. - \ 2009
    Aquaculture 296 (2009)1-2. - ISSN 0044-8486 - p. 45 - 50.
    bass dicentrarchus-labrax - food utilization - nitrogen-excretion - external ammonia - chronic toxicity - atlantic cod - marine fish - water - trout - plasma
    Juvenile turbot (Scophthalmus maximus) were exposed periodically and chronically to different levels of un-ionised ammonia (UIA-N) and the subsequent effect on growth and food conversion efficiency was studied. Fish with a mean (SD) initial weight 19.3 (3.9) g, were exposed to five treatments consisting of a control group, two groups (ChronicLow and ChronicHigh, UIA-N levels of 0.13 and 0.25 mg l- 1, respectively) chronically exposed to ammonia and two groups (LowPulse and HighPulse) exposed to the same levels as above for a short period daily. The fish were held for 64 days at 18 °C, a pH of 8.04 and a salinity of 33.5‰. At the end of the experiment, fish from the Control group had a significantly higher mean weight (95.5 g) compared to all other groups. Fish from the ChronicHigh group displayed the lowest mean weight (74.6 g), whereas fish in the ChronicLow, LowPulse and HighPulse groups displayed mean weights of: 79.3 g, 82.8 g and 81.9 g, respectively. Blood ion concentrations were not affected significantly in any of the treatments, whereas minor reductions in blood pH, partial pressure of CO2 and total CO2 content were found in ammonia exposed groups up until day 44 of the experiment. Feed conversion efficiency, daily feeding rate and total feed consumption did not vary significantly between treatments. The study demonstrate that short daily ammonia peaks may result in negative effects on growth, equivalent to that found under chronic ammonia exposure in juvenile turbot.
    Interactive effects of dietary crude protein and fermentable carbohydrate levels on odour from pig manure
    Le, D.P. ; Aarnink, A.J.A. ; Jongbloed, A.W. ; Peet-Schwering, C.M.C. van der; Ogink, N.W.M. ; Verstegen, M.W.A. - \ 2008
    Livestock Science 114 (2008)1. - ISSN 1871-1413 - p. 48 - 61.
    growing-finishing pigs - volatile fatty-acids - nitrogen-excretion - ammonia emission - nonstarch polysaccharide - swine manure - slurry - fiber - colon - volatilization
    The objective of this study was to determine the effects of dietary levels of crude protein (CP) and levels of fermentable carbohydrates (FC) and their interaction on odour emission, odour intensity, odour hedonic tone, and ammonia emission from pig manure, and manure characteristics. An experiment was conducted with finishing pigs (n = 36) in a 2 × 3 factorial randomized complete block arrangement with 6 treatment combinations in 6 blocks. There were 2 dietary CP levels (low 12%; high 18%) and 3 digestible FC levels: (low 95.5; medium 145.5; and high 195.5 g/kg feed, as-fed basis). Pigs with an initial body weight (BW) of 57.7 ± 2.5 kg were penned individually in partly slatted floor pens. Faeces and urine of each pig accumulated in separate manure pits under the slatted floor. In the 6th week of the collection period air samples were collected directly above the manure in each pit. Manure samples were taken for manure characteristics. Air samples were analyzed for odour concentration and for hedonic tone and odour intensity. Manure samples were analyzed for volatile fatty acids (VFA), indoles, phenoles, sulphurous compounds, ammonium, and total N concentrations. Dietary CP level and FC level did not affect odour emission, odour intensity and hedonic tone but their interaction affected odour emission at P = 0.06. At a high dietary CP level, increased FC level decreased odour emission, while at a low CP level, increased FC level increased odour emission from pig manure. Total N and ammonium concentrations, and ammonia emission from pig manure were reduced at low dietary CP level (P <0.001). High FC level led to low ammonia emission from pig manure (P = 0.01). Manure pH increased at high dietary CP level (P <0.001) and decreased when FC level increased (P <0.05). Total VFA concentration increased at high dietary CP level (P <0.001) and when FC level increased (P <0.001). Enhanced dietary CP increased the manure concentrations of phenol (P <0.001), cresols (P = 0.01), indole (P <0.001), 4-ethylphenol (P <0.001) and carbon disulfide (P <0.001), but FC did not affect concentrations of these compounds (P > 0.05) in the manure. We conclude that the interaction between dietary CP and FC plays a role in odour production and emission. Ammonia emission from pig manure can be reduced substantially by decreasing dietary CP and by increasing FC.
    Effects of dietary crude protein level on odour from pig manure
    Le, P.D. ; Aarnink, A.J.A. ; Jongbloed, A.W. ; Peet-Schwering, C.M.C. van der; Ogink, N.W.M. ; Verstegen, M.W.A. - \ 2007
    Animal 1 (2007)5. - ISSN 1751-7311 - p. 734 - 744.
    growing-finishing pigs - nitrogen-excretion - ammonia emission - fattening pigs - slurry - ph - volatilization - offensiveness
    The objective of this study was to determine the effects of dietary crude protein (CP) level on odour emission, odour intensity, hedonic tone, and ammonia emission from pig manure and on manure composition (pH, total nitrogen, ammonium, volatile fatty acids, indolic, phenolic and sulphur-containing compounds). An experiment was conducted with growing pigs (n = 18) in a randomised complete-block design with three treatments in six blocks. Treatment groups were 12%, 15% and 18% CP diets. Barley was exchanged for soya-bean meal. Crystalline amino acids (AA) were included in the 12% CP diet up to the level of pigs' requirement, the same amount of AA was added to the 15% and 18% CP diets. Pigs with an initial body weight (BW) of 36.5 +/- 3.4 kg (mean +/- s.d.) were individually penned in partly slatted floor pens and offered a daily feed allowance of 2.8 x maintenance requirement for net energy (NE: 293 kJ/kg BW0.75). Feed was mixed with water, 1/2.5 (w/w). Faeces and urine of each pig were accumulated together in a separate manure pit under the slatted floor After an adaptation period of 2 weeks, the manure pits were cleaned and manure was collected. In the 5th week of the collection period, air samples for odour and ammonia analyses, and manure samples were collected directly from each manure pit. Air samples were analysed for odour concentration and for hedonic value and intensity above odour detection threshold. Manure samples were analysed for volatile fatty acids, and indolic, phenolic and sulphurous compounds, ammonium and total nitrogen concentrations. Reducing dietary CP from 18% to 12% lowered odour emission (P <0.05) and ammonia emission (P = 0.01) from pig manure by 80% and 53%, respectively. Reduced dietary CP decreased total nitrogen, methyl sulphide, carbon disulphide, ethanethiol, phenol, 4-ethyl phenol, indole and 3-methyl indole concentrations in the manure (P <0.05). Volatile fatty acids and cresols concentrations in the manure of pigs fed different dietary CP levels were similar A reduction of dietary CP and at the same time providing essential AA is an option to reduce odour emission as well as ammonia emission from pig manure.
    Nutrition, key factor to reduce environmental load from pig production
    Aarnink, A.J.A. ; Verstegen, M.W.A. - \ 2007
    Livestock Science 109 (2007)1-3. - ISSN 1871-1413 - p. 194 - 203.
    growing-finishing pigs - ammonia emission - nutrient digestibility - electrolyte balance - livestock buildings - nitrogen-excretion - microbial phytase - animal production - dietary-protein - piggery wastes
    In different parts of Europe animal production is highly concentrated. Pig production generally is the main animal production activity in these areas. Main concerns of these large numbers of pigs are the amount of surplus nutrients in excreta and gaseous losses to the environment. Main nutrients of concern are N, P, and heavy metals and main gaseous losses of concern are ammonia, odour, and methane. Although losses are inevitable to a certain extent, nutrition seems to be a key factor in reducing these losses. Main nutritional strategies to reduce N and P excretions from pigs are: phase feeding (N, P), supplementation of limiting amino acids to the diet (N), and addition of phytase to the diet (P). Nutritional strategies to reduce heavy metals excretions from pigs are: finding alternative, natural, growth promoters that could replace Cu and Zn in the diet; using feedstuffs for the diet that are less contaminated with Cd. Main strategies to reduce ammonia emissions are: 1) lowering crude protein intake in combination with addition of limiting amino acids; 2) Shifting nitrogen excretion from urine to faeces by including fermentable carbohydrates in the diet; 3) lowering pH of urine by adding acidifying salts to the diet; 4) lowering the pH of faeces by inclusion of fermentable carbohydrates in the diet. These strategies proved to be independent from each other and effects are additive. By combining these strategies a total reduction of ammonia emission in growing-finishing pigs of 70% could be reached. Strategies to reduce odour emission are: 1) reducing protein fermentation by balancing available protein and fermentable carbohydrates in the large intestine; 2) Minimizing breakdown of absorbed sulphur amino acids. More studies are needed in this area of research, but results until now are very promising. A clear relationship exists between fermentable carbohydrates in the diet and methane emissions. This disadvantage should be considered when tackling ammonia emission by this strategy. It is concluded that there is a large potential to reduce environmental load within pig dense areas by nutritional means.
    Odour from animal production facilities: its relationship to diet
    Aarnink, A.J.A. ; Dinh Phung, P.D. Le; Ogink, N.W.M. ; Becker, P.M. ; Verstegen, M.W.A. - \ 2005
    Nutrition Research Reviews 18 (2005)1. - ISSN 0954-4224 - p. 3 - 30.
    growing-finishing pigs - volatile sulfur-compounds - gamma-mercaptomethane-lyase - acid-supplemented diets - reduced-crude protein - l-methionine - nitrogen-excretion - swine manure - carcass characteristics - growth-performance
    Though bad odour has always been associated with animal production, it did not attract much research attention until in many countries the odour production and emission from intensified animal production caused serious nuisance and was implicated in the health problems of individuals living near animal farms. Odour from pig production facilities is generated by the microbial conversion of feed in the large intestine of pigs and by the microbial conversion of pig excreta under anaerobic conditions and in manure stores. Assuming that primary odour-causing compounds arise from an excess of degradable protein and a lack of specific fermentable carbohydrates during microbial fermentation, the main dietary components that can be altered to reduce odour are protein and fermentable carbohydrates. In the present paper we aim to give an up-to-date review of studies on the relationship between diet composition and odour production, with the emphasis on protein and fermentable carbohydrates. We hypothesise how odour might be changed and/or reduced by altering the diet of pigs. Research so far has mainly focused on the single effects of different levels of crude protein and fermentable carbohydrates on odour production. However, also important for odour formation are the sources of protein and fermentable carbohydrates. In addition, it is not only the amount and source of these compounds that is important, but also the balance between them. On the basis of our review of the literature, we hypothesise that odour nuisance from pig production facilities might be reduced significantly if there is an optimum balance between protein and fermentable carbohydrates in the diet of pigs
    Check title to add to marked list

    Show 20 50 100 records per page

     
    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.