bluuebunny/crossref_metadata_2025 huggingface dataset:
Digestion of proteins of varying degradability in sheep. 1. Fermentation in and rate of passage from the reticulorumen.
Authors: Bruchem J. van , Rouwers S.M.G. , Bangma G.A. , Leffering C.P. , Adrichem P.W.M. van
Published: June 2020

Sugarbeet pulp, citrus pulp, sugarbeet molasses and minerals and vitamins were mixed with different amounts of groundnut expeller, potato protein, peas or dried brewers' grains to give 6 concentrates with protein solubility from 7 to 51%. The concentrates (600 g daily) were given with rye grass (300 g daily) to 2 Texel wethers weighing about 70 kg with a cannula in the dorsal rumen sac. With increasing degradability of protein, rumen fermentation was less stable, the diurnal variation and content of ammonia in rumen fluid were increased, the ratio of non-glucogenic to glucogenic volatile fatty acids decreased and the dilution rate of rumen fluid increased. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effect of pen size on the development of agonistic behaviour in piglets.
Authors: Lammers G.J. , Schouten W.G.P.
Published: June 2020

Litters of piglets (7-9 piglets) were housed with a tethered sow in pens of 28, 6.7 or 3.5 msuperscript 2 for the first 8 weeks of life. From videorecordings of behaviour interactions between piglets within litters, it was concluded that for the development of normal agonistic behaviour in group-housed pigs it was very important that pens should be larger than 3.5msuperscript 2. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Simple model for daily evaporation from fallow tilled soil under spring conditions in a temperate climate.
Authors: Boesten J.J.T.I. , Stroosnijder L.
Published: June 2020

A simple parametric model is presented to estimate daily evaporation from fallow tilled soil under spring conditions in a temperate climate. In this model, cumulative actual evaporation during a drying cycle is directly proportional to the square root of cumulative potential evaporation. The model contains only one soil parameter. Evidence from a literature study indicates that this model is an improvement on models proposed previously in which cumulative actual evaporation is related to the square root of time.
The model was used to calculate evaporation from fallow loamy sand in the Netherlands in spring and summer. A literature study showed that evaporation characteristics of sieved soils as determined in the laboratory are not valid for field soils. Therefore the single evaporation parameter was determined by a quick and cheap microlysimeter technique. In a limited field test, measured and predicted cumulative evaporation in periods of 5, 8 and 34 days were found to correspond reasonably well. The evaporation model together with a simple soil water flow model were found to describe quite well moisture profiles in field soil under a range of conditions. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effect of black peat, pH and Mg on growth of heather on sandy soil.
Authors: Niers H. , Boon J. van der
Published: June 2020

Eight field trials were carried out with various heather cultivars (Calluna vulgaris Carmen, Cuprea, Robert Chapman; Erica tetralix Con Underwood; E. carnea [herbacea] King George and E. cinerea C.D. Eason). Peat at 0-8 msuperscript 3/100 msuperscript 2 was incorporated into the top soil or applied as a layer and soil pH-KCl was maintained at levels between 3 and 6.8. Increasing peat application up to 4 msuperscript 3/100 msuperscript 2 improved the growth and quality (visual rating) of the stand; higher amounts had little additional effect. Peat applied as a layer gave some slightly better results than peat incorporated into the topsoil. A soil pH-KCl value of 4.2 was the optimum for growth of most cultivars and reasonable growth could be expected in the range 3.8-4.7. Cv. King George was more tolerant to high pH than cultivars of the other species tested. In 3 trials with Calluna cultivars MgO application at 150 or 200 kg/ha increased the Mg content of the soil and shoots but had a slight negative effect on growth. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Transfer of cadmium, lead, mercury and arsenic from feed into milk and various tissues of dairy cows: chemical and pathological data.
Authors: Vreman K. , Veen N.G. van der , Molen E.J. van der , Ruig W.G. de
Published: June 2020

In the 1st trial, lasting 3 months, 24 cows in 2 groups were given daily 15 kg roughage and 3 kg concentrates without (control) or with soluble compounds of heavy metals (including As2O5) added to the concentrates to give Cd, Pb, Hg and As at 2, 50, 0.2 and 3.4 (control) and 152, 200, 1.7 and 33 mg/day (treatment) resp. In the 2nd trial, lasting 2-3 lactations, 32 cows in 4 groups were kept indoors and given daily 10 kg roughage and 10-11 kg concentrates without or with soluble compounds (including As2O3), harbour sludge or sewage sludge. Intakes of Cd, Pb, Hg and As by control cows were the same as those in the 1st trial, but for cows in the 3 treatment groups daily intakes averaged: Cd 32, 10 and 6 mg; Pb 200, 164 and 168 mg; Hg 1.7, 3.1 and 1.2 mg; and As 33, 21 and 6.8 mg. In neither trial did increased intakes of Cd, Pb, Hg or As lead to significantly increased concn. in milk or blood, and only As given in soluble compounds was increased in muscle from slaughtered cows (4/group in trial 1 and 1-2/group in trial 2). Concentrations of Cd, Pb, Hg and As in liver and kidney were all increased by the treatments, and particularly by soluble compounds, with concn. in kidney exceeding those in liver in all but 1 case. Cd also accumulated in spleen and thymus, Pb in bone, Hg in spleen, and As in heart, thymus, spleen and brain. Results are compared with those obtained in other carry-over studies. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Use of inductively coupled plasma atomic emission spectrometry for determination of iron, aluminium and phosphorus in Tamm's soil extracts.
Authors: Novozamsky I. , Eck R. van , Houba V.J.G. , Lee J.J. van der
Published: June 2020

Fe, Al and P were determined by ICP atomic emission spectrometry in an ammonium oxalate-oxalic acid extract of soil. Measuring conditions were optimized towards P. Transport interferences were prevented by diluting and acidifying the sample solutions. Spectral interferences on P were found with Fe, Al and Cu. A correction may be made for soils high in Al and/or Fe. The analytical results showed good agreement with other methods. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Quantified land evaluation (QLE) procedures, a new tool for land-use planning.
Authors: Driesen P.M.
Published: June 2020

Qantified Land Evaluation (QLE) procedures have been developed by the Centre for World Food Studies in Amsterdam to assist planners to devise better development strategies which aim at sustainable agricultural production. They use concepts as defined in the FAO Framework on Land Evaluation (1976). Land evaluation is shown to concern not only the technical aspects of agricultural production but also the socioeconomic, political and other conditions under which production takes place in existing or projected land use systems. The QLE approach presented is part of a much wider analytical framework that supports the development of national food policies. The paper discusses the following factors as related to the new procedure: the production situation, the simulation procedure, regional analysis, and application of quantified land evaluation procedures. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Geographic information for land-use management.
Authors: Kleef H. van , Linthorst T.J.
Published: June 2020

Interest in non-urban areas in the Netherlands has greatly increased. This necessitates careful management, especially in rural areas which are affected by the influence of urbanization. Knowledge of the local situation is increasingly important. These trends have had a considerable impact on the development of land use planning and policy. The number of computerized information systems for geographic information has increased considerably. New techniques have been developed to collect and present geographic information, by means of digitizing maps and the use of drawing machines in direct communication with computers. The paper discusses the requirements of geographic information systems with special attention to linking of geographic data and flexible output. Finally, some developments in land use management are presented. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Towards soil compaction limits for crop growth.
Authors: Boone F.R.
Published: June 2020

The various relationships found between soil compaction and crop growth are discussed and the relation between soil compaction and soil structure considered. The factors which are relevent to crop growth and which are affected by compaction and the need for an index of soil structure are discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Influence of level and composition of concentrate supplements on rumen fermentation patterns of grazing dairy cows.
Authors: Vuuren A.M. van , Koelen C.J. van der , Vroons-de Bruin J.
Published: June 2020

In a 2 x 2 Latin square design trial 6 grazing dairy cows, with rumen cannula, were supplemented with high-starch concentrate, containing starch 248 g/kg DM, or low-starch concentrate (starch 15 g/kg DM). Cows were given daily 1 kg high-starch concentrate (1HS), 7 kg high-starch concentrate (7HS) or 7 kg low-starch concentrate (7LS) in equal meals fed at 0600 and 1600 h. After 3 weeks of adaptation, rumen samples were taken at 4-h intervals in two 24-h periods. In the first 24-h period samples from the swards (80-90% Lolium perenne) were taken immediately before rumen sampling. Total sugar content of herbage increased during daytime with the highest content directly before sunset. Patterns of ruminal pH values were not different between treatment and values were minimum at 2400 h. Volatile fatty acids (VFA) and ammonia peaked at 2400 h. Extra high- or low-starch concentrate decreased ruminal content of ammonia 19, 13 and 12 mmol/litre for treatments 1HS, 7HS and 7LS and also decreased branched-chain VFA. Acetate:propionate and non-glucogenic:glucogenic ratios within VFA and percentage of milk fat were lowest for treatment 7HS. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The behaviour of grower pigs in relation to housing systems.
Authors: Ruiterkamp W.A.
Published: June 2020

Two slatted floor systems and the Danish system were compared to investigate how grower pigs function in modern, intensive housing systems. Based on performance results, data on culled animals and behavioural data, it was concluded that the well-being of grower pigs is more impaired in slatted floor systems than in the Danish system. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Development and prevention of preputial sucking in veal calves.
Authors: Wilt J.G. de
Published: June 2020

The development of the sucking behaviour of bucket-fed veal calves in groups of five was described from the age of two to eight weeks. The influence of extra water supply and early feeding method on the occurrence of preputial sucking was investigated. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The effect of compaction of the arable layer in sandy soils on the growth of maize for silage. 2. Soil conditions and plant growth.
Authors: Boone F.R. , Werf H.M.G. van der , Kroesbergen B. , Hag B.A. ten , Boers A.
Published: June 2020

Silage maize cv. Brutus was grown on 3 soil types in 1980-82 on (a) loose soil, (b) soil lightly compacted with a packer at ploughing, (c) soil moderately compacted using a tractor with double rear wheels, (d) soil heavily compacted using a tractor with single rear wheels. Crop growth responses varied over time in relation to growth stage and amount of rainfall. There were small yield reductions in loose soil, and large reductions in heavily compacted soil resulting from insufficient soil aeration. Results were greatly influenced by rainfall pattern and local variations in drainage status. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effects of plant density and nitrogen fertilization in winter wheat (Triticum aestivum L.). 1. Production pattern and grain yield.
Authors: Ellen J.
Published: June 2020

Winter wheat cv. Arminda sown on 8 Oct. 1979 at 45 or 125 kg seed/ha was given 60 kg N/ha between 29 Mar. and 23 May at Zadoks growth stage 22, 27, 30, 31, 32 or 37, and a further 80 kg N/ha on 6 June at Zadoks stage 45. Delay in applying N reduced the number of tillers/plant and increased the number of grains/ear but had little effect on number of grains/msuperscript 2, progressively decreased 1000-grain wt and decreased leaf area per plant, per tiller and per msuperscript 2. Higher shoot wt before anthesis was more closely correlated with final grain wt than with grain number. Main stems and side tillers differed in development, growth rate, leaf area, specific leaf area and ear DM content. N uptake was faster the later the N was applied but the efficiency of that N in DM production was reduced and the N content of vegetative plant parts, particularly at low plant density, and of grain was considerably increased. Contents and amounts of water-soluble carbohydrates in stems, leaves and chaff were generally lower at low plant density. Differences in date of N application resulted in different levels and amounts of water-soluble carbohydrates at ripening. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effects of plant density and nitrogen fertilization in winter wheat (Triticum aestivum L.). 2. Incidence of Gerlachia nivalis and Fusarium spp. related to yield losses.
Authors: Ellen J. , Langerak C.J.
Published: June 2020

At the low plant density there was more infection by G. [Monographella] nivalis and F. spp. than at the high plant density. In the post-floral period this effect was reflected in a more severe attack of the vegetative plant parts and a greater number of grains being infected at the time of harvest. Delaying the first N dressing and/or the supplementary nitrogen fertilizations at a later stage in the growing season enhanced attack by M. nivalis and F. spp. M. nivalis was the most important; 75% of the attacked grains were infected by it. It is concluded that seed producers should apply nitrogen only in the early stages of plant development, which may reduce considerably the transmission of these pathogens to the new seeds. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Stimulation of vegetation growth on raised coastal fore-dune ridges.
Authors: Putten W.H. van der , Gulik W.J.M. van
Published: June 2020

In experiments to reduce the establishment time of Ammophila arenaria on sand dunes, bundles of 6 ramets placed so that the rhizomes were horizontal and the sprouts upwards produced significantly more (241) tillers/msuperscript 2 than the traditional method (vertical planting, 80 tillers/msuperscript 2). In sowing trials, disc harrowing 5 t straw/ha to stabilize the sand allowed 160 seedlings/msuperscript 2 to germinate after winter, while other methods of stabilizing the sand were unsatisfactory. Scattering rhizomes with dormant buds at 60/msuperscript 2 followed by disc harrowing to 10-15 cm and addition of slow-release NPK gave 43-67 tillers/msuperscript 2 within 1 year, but the surface needed stabilizing until emergence. Slow-release NPK at 90 + 20 + 20 kg/ha gave 1.7 times more tillers than did 45 + 10 + 10 kg/ha. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Adsorption of copper, cadmium and lead from aqueous solution to the kaolinite/water interface.
Authors: Schindler P.W. , Liechti P. , Westall J.C.
Published: June 2020

The adsorption of Cu (II), Cd (II) and Pb (II) from aqueous solution to the kaolinite/water interface has been studied at 298.2 K as a function of both pH and ionic strength of the aqueous phase. The extent of adsorption increases with increasing pH and with decreasing ionic strength. Both effects can be explained by a model that assumes two kinds of binding sites: (a) weakly acidic groups XH that account for ion exchange, and (b) ampholytic surface hydroxyls SOH which form inner sphere complexes with the divalent metal ions. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The Cs-137 contamination of soils in the Netherlands and its consequences for the contamination of crop products.
Authors: Frissel M.J. , Stoutjesdijk J.F. , Koolwijk A.C. , Koster H.W.
Published: June 2020

On 2-4 May 1986 the Netherlands was contaminated with radioactive caesium originating from the nuclear accident at Chernobyl. Radiation measurements indicated that the major part of the contamination was associated with rainfall. A sampling and analysis programme confirmed this assumption. To estimate the uptake of Cs-134 and Cs-137 by crops in the future, use was made of the data of the Soil-to-Plant Transfer working group of the IUR (International Union of Radioecologists). The IUR data provide predictor values for the transfer of radionuclides for particular types of crops and soils. Correction factors are presented for the impact of pH, organic matter content and reduction of the availability of radionuclides with time. Uncertainties associated with averaging time and space effects and local differences as well as 95% confidence limits are provided. The predicted levels for edible parts of crops in the Netherlands vary between 0.1 and 10 Bq kg-1 on a dry weight base. On a fresh weight base these values are even lower. The predicted transfer values are compared with results of uptake experiments at RIVM. It can be concluded that, for the range of conditions tested, there is no indication of severe deviations from the predicted uptake due to local conditions in the Netherlands. Therefore the derived equations for the prediction of the uptake of Cs-137 can be applied. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Measurement of matric flux potential: a simple procedure for the hydraulic characterization of soils.
Authors: Berge H.F.M. ten , Metselaar K. , Stroosnijder L.
Published: June 2020

A new, simple and non-destructive method is proposed to measure directly soil matric flux potential as a function of water content. Soil water diffusivity is then found by differentiation of the measured curve. The steady-state method is based on a two-parameter expression for matric flux potential; it requires few observations, obtained by standard equipment, but it is relatively slow. Specific advantages are the method's applicability to the hydraulic characterisation of thin, brittle or hard samples. Experimental examples are presented and a theoretical analysis of errors due to gravity and non-stationarity is included. Where the integral characteristic matric flux potential is of interest, direct assessment gives more accurate results than integration of a measured diffusivity curve. (Abstract retrieved from CAB Abstracts by CABI’s permission)
On the measurement of air permeability.
Authors: Groenevelt P.H. , Lemoine G.G.
Published: June 2020

Air pemeability values are used to assess the state of aeration, soil structural stability, structural degradation and compaction. A simple experimental procedure, using a constant-speed motor, a syringe and simple pressure sensors, is discussed.
At steady-state air flow throught a soil sample the air permeability coefficient can be derived directly from Kirkham's equation. For transient conditions an equation is presented, based on a combination of Kirkham's equation and the ideal gas law, from which the air permeability coefficient can be deduced by trial and error.
The importance of the soil water potential, in relation to the measurement of air permeability, is discussed. Complications arising from the 'non-ideal' behaviour of the pressure sensor are also discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
A small rainfall simulator for the determination of soil erodibility.
Authors: Kamphorst A.
Published: June 2020

A small rainfall simulator is described, which can be used in the field as well as in the laboratory for the determination of infiltration and erosion characterisitcs of soils. It is particularly suitable for soil conservation surveys, as it is light to carry and easy to handle in the field.
A description is given of a standard procedure for the determination of topsoil erodibilities in the field and some results are presented. The method appears to be highly sensitive to soil properties influencing soil erodibility, such as clay content, organic matter content and soil pH. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Soil evaporation: test of a practical approach under semi-arid conditions.
Authors: Stroosnijder L.
Published: June 2020

The role of soil evaporation in the field water balance is briefly reviewed. With an increasing demand for improved soil and water management, the common practice of combining evaporation with transpiration into a single term, i.e. evapotranspiration, is no longer justified. The approach described in this paper combines practical experience with computer modelling.
Bare field soils evaporate at a potential rate only during one or a few days after rainfall. Thereafter, evaporation is reduced due to drying of the soil surface. Both deterministic and parametric modelling often show a roughly linear increase in cumulative evaporation with the square root of time. Theoretically, this holds only if the potential evaporation is constant. This is not the case in some climates: daily potential evaporation rates commonly fluctuate between 1 and 6 mm day-1 or more in temperate climates and in some (sub)tropical climates. In such cases it appears that cumulative actual evaporation relates better to the square root of cumulative potential evaporation than to the sqaure root of time. Evaporation can be described then with a simple equation containing only one soil parameter. The latter can be easily measured, even in tilled fields, with a fast and cheap microlysimeter technique.
This practical approach is illustrated with measurements in the African Sahelian zone as well as in the Netherlands. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Does variation in photosynthetic rate explain variation in growth rate and yield?
Authors: Lambers H.
Published: June 2020

The basis of variation in growth rate and production between and within species is discussed. Examples taken from a wide range of literature and species are used to investigate the role of NAR and the pattern of photosynthate investment in such variation. Variation in photosynthesis is considered in terms of RuBP-carboxylase and N compound concn and leaf anatomy and morphology. Patterns of N distribution within the leaf canopy are briefly discussed together with the potential for improving crop performance by altering plant photosynthetic characteristics. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effects of soil acidity on Douglas fir seedlings. 2. The role of pH, aluminium concentration and nitrogen nutrition (pot experiment).
Authors: Smit H.P. , Keltjens W.G. , Breemen N. van
Published: June 2020

In greenhouse studies, the growth of 1-yr-old Douglas fir (Pseudotsuga menziesii) seedlings decreased and mortality increased with increasing soil acidity when pH was
Effects of short periods of long days on the development, yield and size distribution of potato tuber.
Authors: Struik P.C. , Heusden E. van , Burger-Meijer K.
Published: June 2020

Experiments were carried out to study the effects of short periods (12 or 16 cycles) of long days (24 h) on the development of stolons and tubers, and on the yield and tuber size distribution of potato cv. Bintje. Treatments initiated at an early stage of growth delayed tuber initiation but stimulated stolon elongation and stolon branching, thus increasing the number of tuber incipients. Later treatments merely delayed tuber set or tuber growth. Short treatments did not affect total tuber yield. A prolonged treatment (48 days) increased the yield in 1 of the 3 experiments. Because of these effects on stolon and tuber development, early treatments caused a shift towards smaller tubers, most pronounced when such a treatment was short. In a experiment in which physiologically old seed was used, av. tuber size was increased when the long-day treatment was initiated later. With optimally peforming seed, av. tuber size showed an optimum when the treatment was initiated just prior to or during tuber initiation. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The inheritance of mitochondrial DNA in cattle.
Authors: Reeuwijk A.J. van , Korver S. , Werf J.H.J. van der
Published: June 2020

The effects of mitochondrial DNA on dairy performance are discussed, including possible implications of cytoplasmic inheritance in breeding schemes employing embryo transfer. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The effects of diurnal temperature regimes on growth and yield of glasshouse sweet pepper.
Authors: Bakker J.C. , Uffelen J.A.M. van
Published: June 2020

Growth and yield of Oct.-sown Capsicum annuum, cv. Delphin, were investigated in a greenhouse under 12 day/night temperature regimes (16/15 degrees , 16/21 degrees , 20/12 degrees , 20/15 degrees , 20/18 degrees , 20/21 degrees , 24/12 degrees , 24/15 degrees , 24/18 degrees , 24/21 degrees , 28/15 degrees and 28/21 degrees C) applied during the early post-planting period (early Dec. to mid-Apr.). Fresh weight and leaf number were significantly correlated with 24-h mean temperature, but no significant effect of the day/night temperature amplitude was found. Plant height, leaf area and the leaf-area:length ratio were significantly correlated with 24-h mean temperature and with day/night temperature amplitude. The optimum 24-h mean temperature for vegetative growth was between 21 and 23 degrees . Yields of total and class 1 fruits (kg/msuperscript 2) and numbers of class 1 fruits were greatest at a 24-h mean temperature of 21-21.5 degrees . Raising the 24-h mean air temperature within the range 16.3 to 23.8 degrees significantly reduced the mean fruit weight of class 1 fruits. The day/night temperature amplitude had a significant positive effect on these variables. The effect of the day/night temperature amplitude on vegetative growth and on yield was of minor importance compared with the effect of the 24-h mean temperature. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Factors affecting soluble solids content of muskmelon (Cucumis melo L.).
Authors: Welles G.W.H. , Buitelaar K.
Published: June 2020

The effects of fruit load, leaf area, night temperature, cultivar and ripening stage on the soluble solids content (SSC) of muskmelons were studied in a series of experiments performed during spring, summer and autumn in heated glasshouses. All factors except fruit load were found to affect SSC. In every experiment the duration of the maturation period (i.e. from fruit set to harvest) was positively correlated with SSC. In order to obtain fruits with a high SSC, it is important to achieve a low rate of fruit growth, i.e. a long maturation period. Low night temperatures in the period of fruit growth, a high leaf area, harvesting only ripe fruits and selecting slow-ripening cultivars may contribute to the production of fruits with high SSC. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Digestion of alfalfa and grass silages in sheep. 2. Digestion of protein in reticulorumen and intestines.
Authors: Bruchem J. van , Kies A.K. , Bremmers R. , Bosch M.W. , Boer H. , Adrichem P.W.M. van
Published: June 2020

Wilted lucerne and grass silages were given to mature wethers. Estimates of degradability of proteins in the reticulorumen were lower with diaminopimelic acid (38-71%) than those based on amino acid profiles of dietary, microbial and duodenal proteins (64-87%). Microbial protein synthesis was related to extent of organic matter fermentation in the reticulorumen. Efficiency of protein synthesis was not different between silages. Apparent digestibility of protein and amino acids in the small intestine was lower for lucerne silage (54%) than for grass silage (60-63%), probably caused by a higher DM passage in the small intestine of lucerne silage. Relative to the amino acid profiles of milk protein and beef, histidine and methionine were the first limiting amino acids. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Determinants of food quality perception and their relationships to physico-chemical characteristics: an application to meat.
Authors: Steenkamp J.B.E.M. , Trijp J.C.M.
Published: June 2020

A consumer-oriented approach to quality improvement can assist firms in agribusiness to sustain their profitability. A model of the food-quality perception process of consumers has been developed that can be used by firms to implement such a consumer-oriented quality strategy. An empirical study was conducted for meat to explore the relationships between the variables in the model. Data for the different phases of the model were obtained for a representative sample (n=384) of the total Dutch consumer market for foreroast (m. triceps brachee), pork rib-chop, blade steak and sirloin steak. Half of the sample was asked to evaluate the two pork cuts, while the other half participated in the evaluation of the two beef cuts. Consumers' perceptions of quality can be meaningfully related to the physico-chemical characteristics of the meat cuts. Furthermore, consumers are willing to pay more for better quality meat. [The article is based on a longer 308 page report, in Dutch, No. 29 in the series Produktschap voor Vee en Vlees, available from PUDOC, P.O. Box 4, 6700 AA Wageningen, Netherlands]. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The importance of cassava in world food production.
Authors: Bruijn G.H. de , Fresco L.O.
Published: June 2020

The assumption that the importance of cassava in expanding food production in developing countries is increasing is questioned. Data for a 22-year period indicated that the only tuber crop gaining in importance on a world scale was potatoes. Cassava production had lagged behind population growth in Africa and the relative increase in production was lower than that of maize. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Zinc status of cows as deduced from the liver zinc content.
Authors: Binnerts W.T.
Published: June 2020

The zinc content of cow's liver was estimated in livers collected from slaughterhouses in The Netherlands. A total of 333 samples taken in autumn and early winter had an average Zn content 125+or-29 mg/kg DM, with 32 outliers (Zn 212 mg/kg and higher). The distribution of the high outliers, along a line extending from NW to SE over the country, may be related to geophysical factors, but also to feeding practice. Some very low Zn contents could be found by subtraction of the residual active Zn that is part of enzymes, about 90 mg/kg, and logarithmic transformation. Thus 29 low outliers could be traced, all with effective Zn storage below 10 mg/kg. Hence in the total material, nearly 10% was gravely deficient, some 40% suboptimal, and 10% excessively rich in Zn. Liver Zn seems a good means of assessment of the liver status of cows, on a much shorter time basis than for typical storage elements like copper. As a means of investigating interactions, the method was less satisfactory, at least for Zn relative to copper and iron. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The metabolism of nitrate and proline in the rumen fluid of a cow and its effect on in vivo formation of N-nitrosoproline.
Authors: Broekhoven L.W. van , Davies J.A.R. , Geurink J.H.
Published: June 2020

In a balance trial, 2 cows were fed on hay containing nitrate, proline and N-nitrosoproline (NPRO). No in vivo formation of NPRO was found. NPRO in hay was recovered from the urine and the faeces. Nitrite and proline were metabolized for the greater part in the rumen fluid. So, it was estimated that 10 and 20%, respectively, will enter the abomasum. In spite of a favourable pH in the abomasum no formation of NPRO was found. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Influence of gibberellic acid (GA₃) applied to the crop on growth, yield and tuber size distribution of seed potatoes.
Authors: Bodlaender K.B.A. , Waart M. van de
Published: June 2020

In field trials in the Netherlands in 1982-86, seed potato cv. Jaerla (1982-86), Ostara, Spunta and Alpha (1986 only) crops were given 50 or 100 g GA3/ha foliar-applied at different growth stages. GA3 applied before the beginning of tuberization promoted stem elongation and stolon growth and slightly retarded tuber initiation. In general GA3 application (especially during stolon growth/onset of tuber initiation) increased the number of 28-45 mm sized tubers. The high GA3 rate produced long, curved tubers. Effects of GA3 differed slightly between cultivars. GA3 stimulated flowering especially with cv. Spunta. There were no negative after-effects of GA3 on growth and yield of progeny. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Nitrogen dressing and nutrient absorption of lilies (Asiatic hybrids) on sandy soils.
Authors: Slangen J.H.G. , Krook G.J. , Hendriks C.H.M. , Hof N.A.A.
Published: June 2020

The effect of different amounts (0, 75, 150 and 225 kg/ha) and timings of split application of N on yield and nutrient uptake of 3 hybrid cultivars grown for bulbs was investigated. Efficiency of N-uptake was determined by soil and plant analysis with field experiments in 1983, 1984 and 1985. Leaching of fertilizers applied before planting induced low nutrient efficiencies in sandy soils. Dividing the total N-dressings into 4 monthly applications from Mar. to June or Apr. to July led to a higher N-efficiency, though fertilizers were easily leached with high rainfall. A total of 150 kg N/ha appeared to be adequate. Concentrations of plant nutrients (P, K, Ca, Mg and Na) in mature plants of cultivars Aristo, Connecticut King and Enchantment are presented in relation to bulb yield and N-uptake. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Simulated response of an acid forest soil to acid deposition and mitigation measures.
Authors: Grinsven J.J.M. van , Kros J. , Breemen N. van , Riemsdijk W.H. van , Eek E. van
Published: June 2020

A modified version of the soil-water acidification model ILWAS was applied to an acid forest soil in the 'Hackfort' experimental forest in the Netherlands. Monthly observations of the chemistry of atmospheric and soil water between April 1981 and April 1987 were used. ILWAS overestimated water uptake reduction, which caused overestimation of soil water fluxes by 20%, compared with values predicted by the hydrological model SWATRE. ILWAS does not simulate capillary rise which may lead to overestimation of solute concentrations. Chemical calibration of the ILWAS model to field data was mainly confined to adjustment of the rate constants for nitrification and gibbsite dissolution. Calibration of these rate constants was complicated by effects of cation exchange. ILWAS was too crude to simulate the N-dynamics, which led to a relatively strong variation of simulated NO3 concentration near the end of the growing season. After calibration the ILWAS model was used to predict the effects of 50% reduction of (NH4)2SO4 deposition, of a fertilization experiment with 2.6 kmolc/ha K2SO4 and 8.6 kmolc/ha MgSO4, and of removal of the forest vegetation. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Resource allocation for animal health research.
Authors: Dijk G. van , Verkaik A.P.
Published: June 2020

Animal health management has changed from first-aid approaches towards planned prevention. To optimize health input at the farm level, various economic models can be used. At the sector level, however, both indirect effects and uncertain time dimensions tend to blur results of such modelling. In addition, health management is in its effects increasingly complementary to other sources of technological progress in animal production. Health management is particularly dependent on health research. Therefore, the question of how to allocate research funds is crucial. Solving this problem is only to a limited extent possible via economic modelling techniques. The reason for this is that animal production has developed into a system in which health and production measures are intertwined. These changes are largely scientifically-based and the research system has also become more integrated. As a result, health research cannot be looked at as an independent factor in health control. Hence, it is hard to allocate the costs and benefits to research and research funding. (Abstract retrieved from CAB Abstracts by CABI’s permission)
A simple thermo-electric probe for the measurement of low water flow.
Authors: Leeuwen C.H. van , Visscher G.J.W.
Published: June 2020

A probe for the measurement of thermal conductivity in porous materials (e.g. soils) was modified and used as a sensor to measure the flow rate of water in the range of 0.5 to 5 mm/s. A repeatability of 5% of the measured flow rate in water was obtained. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Influence of wilting on chemical and microbial parameters of grass relevant to ensiling.
Authors: Spoelstra S.F. , Hindle V.A.
Published: June 2020

Plots of Lolium perenne were subjected to the normal farm routine for making wilted silage. The grass was sampled periodically during (generally moist) wilting and analysed for chemical and microbial factors. The daily increase of the ammonium-N content was 5.8 g/kg N; the CF content also tended to increase during wilting (6 +or- 4.3 g/kg DM), though the correlation was poor. The sugar content of the grass and the in vitro digestibility decreased during wilting (9 +or- 6.1 g/kg DM per day and 1.1 +or- 0.11 percentage units/d, resp.). Counts on rogosa agar increased on av. by 0.24 +or- 0.16 logarithmic units (LU)/g DM per day and on MRS agar by 0.13 +or- 0.17 LU/g DM per day. Enterobacteria enumerated on violet red bile glucose agar increased by 0.23 +or- 0.18 LU/g DM per day. Inoculation by spraying the standing grass as an alternative to application on the forage harvester was investigated. In 4 separate trials the standing grass was sprayed with approximately 6.6 LU/g DM of a silage inoculant containing Lactobacillus plantarum. During wilting the counts on rogosa agar declined by 0.72 +or- 0.33 LU/g DM per day and on MRS agar by 0.65 +or- 0.35 LU/g DM per day whereas the counts on the uninoculated control field increased by 0.17 +or- 0.19 and 0.17 +or- 0.17 LU/g DM per day for the rogosa and MRS media, resp. It was concluded that inoculation of the standing grass was probably only useful in combination with a short wilting period. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Relation between flower colour and pigment composition of tulip (Tulipa L.).
Authors: Nieuwhof M. , Eijk J.P. van , Eikelboom W.
Published: June 2020

Colour and pigment composition were determined in flowers of F1 plants produced by crossing tulip cultivars. Yellow flowers contained only carotenoids, orange flowers always at least carotenoids and cyanidin, and red flowers always and pink and purple flowers nearly always cyanidin. Most flowers, except purple ones, did not contain delphinidin. Highest carotenoid levels occurred in yellow, orange, dark red and orange-red flowers; highest delphinidin levels in purple flowers and highest cyanidin and pelargonidin levels in red flowers. Pigment levels in light coloured flowers were lower than in darker coloured flowers. Between flowers with the same colour substantial differences in pigment composition and level may occur, indicating that flower colour of tulip depends additionally on other chemical and physical characters. (Abstract retrieved from CAB Abstracts by CABI’s permission)
A comparison of farmers' sow culling decisions and model recommendations.
Authors: Krabbenborg R.M.M. , Dijkhuizen A.A. , Huirne R.B.M.
Published: June 2020

Culling data on sows recorded on the database of the State Veterinary Faculty, Netherlands were analysed, using an economic replacement model. The model determines a sow's optimum lifespan, and then calculates an economic index, called the retention-pay-off, which is the extra profit to be expected from keeping her until the optimum age and not replacing her immediately. For 1617 sows culled in 12 farms during 1985-86, the loss due to premature culling averaged Dfl. 124 per sow. The retention-pay-off for sows culled due to old age or low litter size was only Dfl.21, while for sows culled due to reproductive problems, it was Dfl.161. Further analysis of sows culled due to reproductive problems showed that those culled for failure to return to oestrus after weaning were being culled too early, while those culled for failure to conceive were being culled too late. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Corpus luteum function in the pig: progesterone profiles of cyclic and pregnant gilts.
Authors: Meulen J. van der , Helmond F.A. , Oudenaarden C.P.J.
Published: June 2020

Progesterone profiles of 7 cycling gilts and those of 6 gilts inseminated on day 1 (1 day after the onset of oestrus) were studied. The results showed that plasma progesterone concentration in the inseminated group was higher (P
Economic comparison of insemination and culling policies in commercial sow herds, assessed by stochastic simulation.
Authors: Houben E.H.P. , Thelosen J.G.M. , Huirne R.B.M. , Dijkhuizen A.A.
Published: June 2020

The simulation model considered 3 culling policies and 3 insemination policies. Culling was classified into unplanned disposal (e.g. fertility, diseases) and planned culling, with a total disposal rate of 55%. The 3 planned culling policies were (1) culling of the oldest sows, (2) culling of sows with the lowest Retention-Pay-Off (RPO, an economic index which ranks sows on future profitability), and (3) culling of sows with the lowest RPO but with the proviso that replacement gilts can also be culled. The 3 insemination policies were: (1) a maximum of 3 inseminations per parity; (2) a maximum of 3 inseminations for parities 1 to 4, 2 for parities 5 to 7 and 1 for sows in other parities and gilts; (3) the number of inseminations depends on the sow's RPO, with a maximum of 3. It was found that culling decisions had a greater effect on profitability than insemination choices. The 3rd culling policy gave the highest profit and the 1st the lowest. It was also shown that the planned disposal rate should be at least 10% of all disposals to yield positive economic effects. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Modelling organic matter dynamics in different soils.
Authors: Verberne E.L.J. , Hassink J. , Willigen P. de , Groot J.J.R. , Veen J.A. van
Published: June 2020

A mathematical model was developed to describe carbon (C) and nitrogen (N) cycling in different soil types, e.g. clay and sandy soils. Transformation rates were described by first-order kinetics. Soil organic matter is divided into four fractions (including microbial biomass pool) and three fractions of residues. The fraction of active soil organic matter was assumed to be affected by the extent of physical protection within the soil, as was the soil microbial biomass. The extent of protection influenced the steady state level of the model, and, hence, the mineralization rates. The mineralization rate in fine-textured soils is lower than in coarse-textured soils; in fine-textured soils a larger proportion of the soil organic matter may be physically protected. The availability of organic materials as a substrate for microorganisms is not only determined by their chemical composition, but also by their spatial distribution in the soil. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Influence of different application rates of nitrogen to soil on rhizosphere bacteria.
Authors: Liljeroth E. , Schelling G.C. , Veen J.A. van
Published: June 2020

The bacterial populations in the rhizosphere of wheat were investigated under different soil nitrogen regimes. Two different levels of nitrogen (250 and 50 mg N per plant) were added as a single application or split in time during growth, and consequently smaller amounts were given each time. The different application methods enabled the study of the bacterial populations in relation to nitrogen concentrations in the roots and in the soil with comparable rates of plant biomass production. When the nitrogen was applied as a single dose at the start of the experiment significantly larger numbers of bacteria (colony forming units) were found in the rhizosphere than in the other treatments. This was correlated with higher nitrogen concentrations in the roots and with higher levels of extractable mineral nitrogen in the soil. In contrast, the numbers of fluorescent pseudomonads were smaller when a high nitrogen rate was applied once. Possible mechanisms for the observed changes in the microbial populations are discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Contribution of atmospheric deposition to heavy-metal concentrations in field crops.
Authors: Dalenberg J.W. , Driel W. van
Published: June 2020

Lolium multiflorum, spring wheat cv. Adonis, carrots and spinach were grown in the field and in a dust-free growth chamber in pots containing soil labelled with 109Cd and 210Pb. The contribution of atmospheric Cd and Pb deposition to plant concn was examined by isotope dilution. Atmospheric deposition contributed 73-95% to the Pb concn of leafy material of L. multiflorum, carrots, spinach, wheat grain and wheat straw. Cd deposition was only significant in wheat grain and straw (21-48%). (Abstract retrieved from CAB Abstracts by CABI’s permission)
Ruminal availability of nitrogen and carbohydrates from fresh and preserved herbage in dairy cows.
Authors: Vuuren A.M. van , Tamminga S. , Ketelaar R.S.
Published: June 2020

Rumen degradabilities of crude protein and non-protein organic matter of fresh and preserved herbage, obtained with nylon bag studies, were compared and consequences for dairy cow rations discussed. Results from 4 experiments indicate that fresh and preserved herbage fertilized at high rates of nitrogen, had a large surplus of fermentable nitrogen. In fresh herbage the ratio of soluble nitrogen:soluble non-protein organic matter ("carbohydrates") was lower than the ratio of insoluble, degraded nitrogen:insoluble, degraded carbohydrates. It is concluded that ingredients with a low ratio of insoluble, degraded nitrogen:insoluble, degraded carbohydrates may be appropriate supplements for grass-based diets. In preserved herbage the ratio of soluble nitrogen:soluble carbohydrates exceeded the ratio of insoluble degraded nitrogen:insoluble degraded carbohydrates. Wilting had no consistent effect on the ratios of nitrogen:carbohydrates. Treatment with cell wall degrading enzymes gave a lower ratio of soluble nitrogen:soluble carbohydrates. It is suggested that silage-based diets require supplementation with ingredients high in soluble carbohydrates. (Abstract retrieved from CAB Abstracts by CABI’s permission)