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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    Effect of olive mill wastewater phenol compounds on reactive carbonyl species and Maillard reaction end-products in ultrahigh-temperature-treated milk
    Troise, A.D. ; Fiore, A. ; Colantuono, A. ; Kokkinidou, S. ; Peterson, D.G. ; Fogliano, V. - \ 2014
    Journal of Agricultural and Food Chemistry 62 (2014)41. - ISSN 0021-8561 - p. 10092 - 10100.
    advanced glycation endproducts - nonfat dry milk - amino-acids - flavor components - mass-spectrometry - heat-treatment - model systems - bovine-milk - lc-ms - protein
    Thermal processing and Maillard reaction (MR) affect the nutritional and sensorial qualities of milk. In this paper an olive mill wastewater phenolic powder (OMW) was tested as a functional ingredient for inhibiting MR development in ultrahigh-temperature (UHT)-treated milk. OMW was added to milk at 0.1 and 0.05% w/v before UHT treatment, and the concentration of MR products was monitored to verify the effect of OMW phenols in controlling the MR. Results revealed that OMW is able to trap the reactive carbonyl species such as hydroxycarbonyls and dicarbonyls, which in turn led to the increase of Maillard-derived off-flavor development. The effect of OMW on the formation of Amadori products and N-e-(carboxymethyl)-lysine (CML) showed that oxidative cleavage, C2–C6 cyclization, and the consequent reactive carbonyl species formation were also inhibited by OMW. Data indicated that OMW is a functional ingredient able to control the MR and to improve the nutritional and sensorial attributes of milk
    Phosphorylation of as1-casein is regulated by different genes
    Bijl, E. ; Valenberg, H.J.F. van; Huppertz, T. ; Hooijdonk, A.C.M. van; Bovenhuis, H. - \ 2014
    Journal of Dairy Science 97 (2014)11. - ISSN 0022-0302 - p. 7240 - 7246.
    milk protein-composition - mammary-gland - dairy-cattle - casein kinase - bovine-milk - association - dgat1 - polymorphism - specificity - cows
    Casein phosphorylation is a posttranslational modification catalyzed by kinase enzymes that attach phosphate groups to specific AA in the protein sequence. This modification is one of the key factors responsible for the stabilization of calcium phosphate nanoclusters in casein micelles and for the internal structure of the casein micelles. aS1-Casein (as1-CN) is of special interest because it constitutes up to 40% of the total casein fraction in milk, and it has 2 common phosphorylation states, with 8 (aS1-CN-8P) and 9 (aS1-CN-9P) phosphorylated serine residues. Factors affecting this variation in the degree of phosphorylation are not currently known. The objective of this research was to determine the genetic background of aS1-CN-8P and aS1-CN-9P. The genetic and phenotypic correlation between aS1-CN-8P and aS1-CN-9P was low (0.18 and 0.19, respectively). This low genetic correlation suggests a different genetic background. These differences were further investigated by means of a genome-wide association study, which showed that both aS1-CN-8P and aS1-CN-9P were affected by a region on Bos taurus autosome (BTA) 6, but only aS1-CN-8P was affected by a region on BTA11 that contains the gene that encodes for ß-lactoglobulin (ß-LG), and only aS1-CN-9P was affected by a region on BTA14 that contains the diacylglycerol acyltransferase 1 (DGAT1) gene. Estimated effects of ß-LG protein genotypes showed that only aS1-CN-8P was associated with the ß-LG A/B polymorphism (g.1772G>A and g.3054C>T); the AA genotype of ß-LG was associated with a lower concentration of aS1-CN-8P (-0.32% wt/wt) than the BB genotype (+0.41% wt/wt). Estimated effects of DGAT1 K232A genotypes showed that only aS1-CN-9P was associated with the DGAT1 gene polymorphism; DGAT1 AA genotype was associated with a higher aS1-CN-9P concentration (+0.53% wt/wt) than the DGAT1 KK genotype (-0.44% wt/wt). The results give insight in phosphorylation of aS1-CN-8P and aS1-CN-9P, which seem to be regulated by a different set of genes.
    Comprehensive peptidomic and glycomic evaluation reveals that sweet whey permeate from colostrum is a source of milk protein-derived peptides and oligosaccharides
    Dallas, D.C. ; Weinborn, V. ; Moura Bell, J.M.L.N. de; Wang, M. ; Parker, E.A. ; Guerrero, A. ; Hettinga, K.A. ; Lebrilla, C.B. ; German, J.B. ; Barile, D. - \ 2014
    Food Research International 63 (2014)part B. - ISSN 0963-9969 - p. 203 - 209.
    holstein-friesian colostrum - globule-membrane proteome - bovine-milk - mass-spectrometry - peptone fraction - beta-casein - chromatography - proteolysis - components - system
    Whey permeate is a co-product obtained when cheese whey is passed through an ultrafiltration membrane to concentrate whey proteins. Whey proteins are retained by the membrane, whereas the low-molecular weight compounds such as lactose, salts, oligosaccharides and peptides pass through the membrane yielding whey permeate. Research shows that bovine milk from healthy cows contains hundreds of naturally occurring peptides – many of which are homologous with known antimicrobial and immunomodulatory peptides – and nearly 50 oligosaccharide compositions (not including structural isomers). As these endogenous peptides and oligosaccharides have low-molecular weight and whey permeate is currently an under-utilized product stream of the dairy industry, we hypothesized that whey permeate may serve as an inexpensive source of naturally occurring functional peptides and oligosaccharides. Laboratory fractionation of endogenous peptides and oligosaccharides from bovine colostrum sweet whey was expanded to pilot-scale. The membrane fractionation methodology used was similar to the methods commonly used industrially to produce whey protein concentrate and whey permeate. Pilot-scale fractionation was compared to laboratory-scale fractionation with regard to the identified peptides and oligosaccharide compositions. Results were interpreted on the basis of whether industrial whey permeate could eventually serve as a source of functional peptides and oligosaccharides. The majority (96%) of peptide sequences and the majority (96%) of oligosaccharide compositions found in the laboratory-scale process were mirrored in the pilot-scale process. Moreover, the pilot-scale process recovered an additional 33 peptides and 1 oligosaccharide not identified from the laboratory-scale extraction. Both laboratory- and pilot-scale processes yielded peptides deriving primarily from the protein ß-casein. The similarity of the laboratory- and pilot-scale's resulting peptide and oligosaccharide profiles demonstrates that whey permeate can serve as an industrial-scale source of bovine milk peptides and oligosaccharides.
    Factors influencing casein micelle size in milk of individual cows: Genetic variants and glycosylation of k-casein
    Bijl, E. ; Vries, R.F.M. de; Valenberg, H.J.F. van; Huppertz, T. ; Hooijdonk, A.C.M. van - \ 2014
    International Dairy Journal 34 (2014)1. - ISSN 0958-6946 - p. 135 - 141.
    protein-composition - bovine-milk - liquid-chromatography - electrophoresis - polymorphism - coagulation - genotypes - pattern - cattle
    The average casein micelle size varies widely between milk samples of individual cows. The factors that cause this variation in size are not known but could provide more insight into casein micelle structure and into the physiology of casein micelle formation. The objective of this research was therefore to determine factors that influence average casein micelle size in milk from individual cows. Average casein micelle size of milk samples was associated with the A and B genetic variants of k-casein, and differences in concentration of glycosylated k-casein as a fraction of total milk protein. Milk samples with a low average casein micelle size were associated with the B variant of k-casein and a higher relative concentration of glycosylated k-casein, compared with milk samples with a high average casein micelle size. Differences observed may be attributed to the effect of glycosylated k-casein groups on casein micelle formation in the mammary gland.
    Oligosaccharides in goat milk: structure, health effects and isolation
    Kiskini, A. ; Difilippo, E. - \ 2013
    Cellular and Molecular Biology 59 (2013)1. - ISSN 0145-5680 - p. 25 - 30.
    lactose-derived oligosaccharides - field h-1-nmr spectroscopy - ceramic membranes - fucosylated oligosaccharides - bifidobacterium-bifidum - deicher antibodies - induced colitis - caprine milk - bovine-milk - colostrum
    Oligosaccharides have been widely recognized for their prebiotic and anti-infective properties. Among the different types of mammalian milk, the one of humans is the richest source of naturally derived oligosaccharides. However, their use as a basis for functional foods is hampered, due to their structural complexity, which in turn makes their re-synthesis extremely difficult. Thus, oligosaccharides from other sources have to be used. In this sense, goat milk constitutes a very appealing candidate, as it contains the highest amount of oligosaccharides among domestic animals, while goat milk oligosaccharides show significant similarities to human milk oligosaccharides from a structural point of view. Studies on goat milk oligosaccharides are scant, and more data is required in order to provide solid clinical evidence of their beneficial effects on humans. The aim of this review is to collect and present the main research findings on goat milk oligosaccharides structure, health effects and isolation.
    Protein, casein and micellar salts in milk: Current content and historical perspectives
    Bijl, E. ; Valenberg, H.J.F. van; Huppertz, T. ; Hooijdonk, A.C.M. van - \ 2013
    Journal of Dairy Science 96 (2013). - ISSN 0022-0302 - p. 5455 - 5464.
    equilibrium thermodynamic model - sterilized concentrated milk - dutch holstein-friesians - calcium-phosphate - inorganic constituents - genetic-parameters - heat-stability - bovine-milk - cows milk - bulk milk
    The protein and fat content of Dutch bulk milk has been monitored since the 1950s and has increased considerably, by 11 and 20%, respectively, whereas milk yield has more than doubled. The change in protein and fat content of milk is advantageous for the dairy industry, as these are the 2 most economically valuable constituents of milk. Increases in protein and fat content of milk have allowed increases in the yield of various products such as cheese and butter. However, for cheese and other applications where casein micelles play a crucial role in structure and stability, it is not only casein content, but also the properties of the casein micelles that determine processability. Of particular importance herein is the salt partition in milk, but it is unknown whether increased protein content has affected the milk salts and their distribution between casein micelles and milk serum. It was, therefore, the objective of this research to determine the salt composition and protein content for individual cow milk and bulk milk over a period of 1 yr and to compare these data to results obtained during the 1930s, 1950s, and 1960s in the last century. Calcium, magnesium, sodium, potassium, and phosphorus content were determined by inductively coupled plasma atomic emission spectrometry and inorganic phosphate, citrate, chloride, and sulfate content by anion-exchange chromatography in bulk milk and milk ultracentrifugate. In addition, ionic calcium and ionic magnesium concentration were determined by the Donnan membrane technique. We concluded that historical increase in milk yield and protein content in milk have resulted in correlated changes in casein content and the micellar salt fraction of milk. In addition, the essential nutrients, calcium, magnesium, and phosphorus in milk have increased the past 75 yr; therefore, the nutritional value of milk has improved. Key words: milk protein , casein , calcium phosphate , magnesium
    Rapid Mastitis Detection assay on porous nitrocellulose membrane slides
    Mujawar, L.H. ; Moers, A.P.H.A. ; Norde, W. ; Amerongen, A. van - \ 2013
    Analytical and Bioanalytical Chemistry 405 (2013)23. - ISSN 1618-2642 - p. 7469 - 7476.
    microarray technology - protein microarrays - bovine-milk - pathogens - antibody - identification - morphology - samples - chip
    We have developed a rapid mastitis detection test based on the immobilization of tag-specific antibody molecules, the binding of double-tagged amplicons, and as a secondary signal a conjugate of black carbon nanoparticles having molecules of a fusion protein of neutrAvidin and alkaline phosphatase at their surface. The antibodies were inkjet printed onto three different nitrocellulose membrane slides, Unisart (Sartorius), FAST (GE Whatman), and Oncyte-Avid (Grace-Biolabs), and the final assay signals on these slides were compared. The blackness of the spots was determined by flatbed scanning and assessment of the pixel gray volume using TotalLab image analysis software. The black spots could be easily read by the naked eye. We successfully demonstrated the detection of specific amplicons from mastitis-causing pathogens in less than 3 h. Using a similar protocol, we also showed that it was possible to detect specific amplicons from four different mastitis-causing pathogens (six strains) on the same pad. The influence of two different printing buffers, phosphate-buffered saline (pH 7.4) and carbonate buffer (pH 9.6), on the functionality of the primary antibodies was also compared.
    Genetic variance in micro-environmental sensitivity for milk and milk quality in Walloon Holstein cattle
    Vandenplas, J. ; Bastin, C. ; Gengler, N. ; Mulder, H.A. - \ 2013
    Journal of Dairy Science 96 (2013)9. - ISSN 0022-0302 - p. 5977 - 5990.
    generalized linear-models - residual variance - breeding values - fatty-acids - production traits - bovine-milk - heterogeneity - variability - prediction - components
    Animals that are robust to environmental changes are desirable in the current dairy industry. Genetic differences in micro-environmental sensitivity can be studied through heterogeneity of residual variance between animals. However, residual variance between animals is usually assumed to be homogeneous in traditional genetic evaluations. The aim of this study was to investigate genetic heterogeneity of residual variance by estimating variance components in residual variance for milk yield, somatic cell score, contents in milk (g/dL) of 2 groups of milk fatty acids (i.e., saturated and unsaturated fatty acids), and the content in milk of one individual fatty acid (i.e., oleic acid, C18:1 cis-9), for first-parity Holstein cows in the Walloon Region of Belgium. A total of 146,027 test-day records from 26,887 cows in 747 herds were available. All cows had at least 3 records and a known sire. These sires had at least 10 cows with records and each herd × test-day had at least 5 cows. The 5 traits were analyzed separately based on fixed lactation curve and random regression test-day models for the mean. Estimation of variance components was performed by running iteratively expectation maximization-REML algorithm by the implementation of double hierarchical generalized linear models. Based on fixed lactation curve test-day mean models, heritability for residual variances ranged between 1.01 × 10-3 and 4.17 × 10-3 for all traits. The genetic standard deviation in residual variance (i.e., approximately the genetic coefficient of variation of residual variance) ranged between 0.12 and 0.17. Therefore, some genetic variance in micro-environmental sensitivity existed in the Walloon Holstein dairy cattle for the 5 studied traits. The standard deviations due to herd × test-day and permanent environment in residual variance ranged between 0.36 and 0.45 for herd × test-day effect and between 0.55 and 0.97 for permanent environmental effect. Therefore, nongenetic effects also contributed substantially to micro-environmental sensitivity. Addition of random regressions to the mean model did not reduce heterogeneity in residual variance and that genetic heterogeneity of residual variance was not simply an effect of an incomplete mean model.
    Differences in milk fat composition predicted by mid-infrared spectrometry among dairy cattle breeds in the Netherlands
    Maurice - Van Eijndhoven, M.H.T. ; Bovenhuis, H. ; Soyeurt, H. ; Calus, M.P.L. - \ 2013
    Journal of Dairy Science 96 (2013)4. - ISSN 0022-0302 - p. 2570 - 2582.
    conjugated linoleic-acid - bovine-milk - genetic-parameters - production traits - short-communication - italian holsteins - desaturase gene - jersey cows - dgat1 gene - polymorphism
    The aim of this study was to estimate breed differences in milk fatty acid (FA) profile among 5 dairy cattle breeds present in the Netherlands: Holstein-Friesian (HF), Meuse-Rhine-Yssel (MRY), Dutch Friesian (DF), Groningen White Headed (GWH), and Jersey (JER). For this purpose, total fat percentage and detailed FA contents in milk (14 individual FA and 14 groups of FA) predicted from mid-infrared spectra were used. Mid-infrared spectrometry profiles were collected during regular milk recording from a range of herds with different combinations of breeds, including both purebred and crossbred cows. The data set used for the analyses contained 41,404 records from a total of 24,445 cows. In total 7,626 cows were crossbreds belonging to the breeds HF, MRY, DF, GWH, and JER; 1,769 purebreds (=87.5%) belonging to the breeds MRY, DF, GWH, and JER; and the other 15,050 cows were HF. Breed effects were estimated using a single-trait animal model. The content in milk of short-chain FA C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, and C16:0 was higher for JER and the content in milk of C16:0 was lower for GWH compared with the other breeds; when adjusting for breed differences in fat percentage, however, not all breed differences were significant. Breed differences were also found for cis-9 C14:1, cis-9 C16:1, C18:0, and a number of C18 unsaturated FA. In general, differences in fat composition in milk between HF, MRY, and DF were not significant. Jerseys tended to produce more saturated FA, whereas GWH tended to produce relatively less saturated FA. After adjusting for differences in fat percentage, breed differences in detailed fat composition disappeared or became smaller for several short- and medium-chain FA, whereas for several long-chain unsaturated FA, more significant breed differences were found. This indicates that short- and medium-chain FA are for all breeds more related to total fat percentage than long-chain FA. In conclusion, between breed differences were found in detailed FA composition and content of individual FA. Especially, for FA produced through de novo synthesis (short-chain FA, C12:0, C14:0, and partly C16:0) differences were found for JER and GWH, compared with the breeds HF, MRY, and DF
    Invited review: Sensors to support health management on dairy farms
    Rutten, C.J. ; Velthuis, A.G.J. ; Steeneveld, W. ; Hogeveen, H. - \ 2013
    Journal of Dairy Science 96 (2013)4. - ISSN 0022-0302 - p. 1928 - 1952.
    automatic milking systems - clinical mastitis detection - economic decision-making - lactating holstein cows - somatic-cell count - estrus detection - electrical-conductivity - bovine-milk - subclinical mastitis - ruminal ph
    Since the 1980s, efforts have been made to develop sensors that measure a parameter from an individual cow. The development started with individual cow recognition and was followed by sensors that measure the electrical conductivity of milk and pedometers that measure activity. The aim of this review is to provide a structured overview of the published sensor systems for dairy health management. The development of sensor systems can be described by the following 4 levels: (I) techniques that measure something about the cow (e.g., activity); (II) interpretations that summarize changes in the sensor data (e.g., increase in activity) to produce information about the cow’s status (e.g., estrus); (III) integration of information where sensor information is supplemented with other information (e.g., economic information) to produce advice (e.g., whether to inseminate a cow or not); and (IV) the farmer makes a decision or the sensor system makes the decision autonomously (e.g., the inseminator is called). This review has structured a total of 126 publications describing 139 sensor systems and compared them based on the 4 levels. The publications were published in the Thomson Reuters (formerly ISI) Web of Science database from January 2002 until June 2012 or in the proceedings of 3 conferences on precision (dairy) farming in 2009, 2010, and 2011. Most studies concerned the detection of mastitis (25%), fertility (33%), and locomotion problems (30%), with fewer studies (16%) related to the detection of metabolic problems. Many studies presented sensor systems at levels I and II, but none did so at levels III and IV. Most of the work for mastitis (92%) and fertility (75%) is done at level II. For locomotion (53%) and metabolism (69%), more than half of the work is done at level I. The performance of sensor systems varies based on the choice of gold standards, algorithms, and test sizes (number of farms and cows). Studies on sensor systems for mastitis and estrus have shown that sensor systems are brought to a higher level; however, the need to improve detection performance still exists. Studies on sensor systems for locomotion problems have shown that the search continues for the most appropriate indicators, sensor techniques, and gold standards. Studies on metabolic problems show that it is still unclear which indicator reflects best the metabolic problems that should be detected. No systems with integrated decision support models have been found. Key words: automated
    Validation of fatty acid predictions in milk using mid-infrared spectrometry across cattle breeds
    Maurice - Van Eijndhoven, M.H.T. ; Soyeurt, H. ; Dehareng, F. ; Calus, M.P.L. - \ 2013
    Animal 7 (2013)2. - ISSN 1751-7311 - p. 348 - 354.
    gas-liquid chromatography - bovine-milk - short-communication - genetic-parameters - spectroscopy - protein
    The aim of this study was to investigate the accuracy to predict detailed fatty acid (FA) composition of bovine milk by mid-infrared spectrometry, for a cattle population that partly differed in terms of country, breed and methodology used to measure actual FA composition compared with the calibration data set. Calibration equations for predicting FA composition using mid-infrared spectrometry were developed in the European project RobustMilk and based on 1236 milk samples from multiple cattle breeds from Ireland, Scotland and the Walloon Region of Belgium. The validation data set contained 190 milk samples from cows in the Netherlands across four breeds: Dutch Friesian, Meuse-Rhine-Yssel, Groningen White Headed (GWH) and Jersey (JER). The FA measurements were performed using gas–liquid partition chromatography (GC) as the gold standard. Some FAs and groups of FAs were not considered because of differences in definition, as the capillary column of the GC was not the same as used to develop the calibration equations. Differences in performance of the calibration equations between breeds were mainly found by evaluating the standard error of validation and the average prediction error. In general, for the GWH breed the smallest differences were found between predicted and reference GC values and least variation in prediction errors, whereas for JER the largest differences were found between predicted and reference GC values and most variation in prediction errors. For the individual FAs 4:0, 6:0, 8:0, 10:0, 12:0, 14:0 and 16:0 and the groups’ saturated FAs, short-chain FAs and medium-chain FAs, predictions assessed for all breeds together were highly accurate (validation R2 > 0.80) with limited bias. For the individual FAs cis-14:1, cis-16:1 and 18:0, the calibration equations were moderately accurate (R2 in the range of 0.60 to 0.80) and for the individual FA 17:0 predictions were less accurate (R2 <0.60) with considerable bias. FA concentrations in the validation data set of our study were generally higher than those in the calibration data. This difference in the range of FA concentrations, mainly due to breed differences in our study, can cause lower accuracy. In conclusion, the RobustMilk calibration equations can be used to predict most FAs in milk from the four breeds in the Netherlands with only a minor loss of accuracy.
    Which factors in raw cow's milk contribute to protection against allergies?
    Neerven, R.J.J. van; Knol, E.F. ; Heck, J.M.L. ; Savelkoul, H.F.J. - \ 2012
    Journal of Allergy and Clinical Immunology 130 (2012)4. - ISSN 0091-6749 - p. 853 - 858.
    gut microbiota - breast-milk - atopic manifestations - immune-responses - oral tolerance - bovine-milk - asthma - oligosaccharides - consumption - disease
    Several epidemiologic studies have shown that growing up in a farming environment is associated with a decreased risk of allergies. A factor that correlates strongly with this effect is the early ingestion of unheated cow's milk. Although, to date, no controlled studies on raw milk consumption have been performed to formally demonstrate this effect, several factors in bovine milk have been described that might explain how raw cow's milk consumption can decrease the risk of allergies. In addition, increasing knowledge on the immunologically active factors in breast milk have also contributed to our understanding of the effects of bovine milk in infants because many of the factors in bovine milk are expected to have functional effects in human subjects as well. Here we review these factors and their mechanisms of action and compare their presence in bovine milk and breast milk. A better understanding of these factors, as well as how to retain them, might ultimately lead to the development of mildly processed milk and infant nutrition products that could become a part of preventive strategies to reduce the incidence of allergic disease
    Characterization of milk fatty acids based on genetic and herd parameters
    Heck, J.M.L. ; Valenberg, H.J.F. van; Bovenhuis, H. ; Dijkstra, J. ; Hooijdonk, A.C.M. van - \ 2012
    Journal of Dairy Research 79 (2012)1. - ISSN 0022-0299 - p. 39 - 46.
    bovine-milk - dairy-cows - mammary-gland - methane production - lactation stage - linseed oil - odd-chain - concentrate - diet - supplementation
    The objective of this study was to characterize the fatty acids (FA) in milk based on genetic and herd parameters to investigate the origin of the different FA in milk. Milk samples of 1912 Dutch Holstein-Friesian cows were analysed for 39 different FA including odd and branched-chain fatty acids. The proportion of variation caused by genetic and herd effects was calculated. In addition, genetic and herd correlations among the fatty acids were estimated and a clustering technique was used to visualise these correlations. The results indicated that in Dutch milk C12:0 is not completely synthesised de novo but also partly blood derived. It was suggested that C20:0 in milk is formed from the action of elongase enzymes on C18:0 and that the odd-chain FA C5:0-C13:0 and a part of C15:0 and C17:0 are synthesised de novo while the other part of C15:0 and C17:0 is blood derived. Furthermore, this work gives an overview of the opportunities to change the concentration of individual FA both by breeding and feeding. It is clearly shown that the extent to which the individual FA can be changed varies greatly and is dependent on the origin of the different FA in milk.
    Whole-genome association study for milk protein composition in dairy cattle
    Schopen, G.C.B. ; Visker, M.H.P.W. ; Koks, P.D. ; Mullaart, E. ; Arendonk, J.A.M. van; Bovenhuis, H. - \ 2011
    Journal of Dairy Science 94 (2011)6. - ISSN 0022-0302 - p. 3148 - 3158.
    quantitative trait loci - genetic-polymorphism - beta-lactoglobulin - missense mutation - alpha-lactalbumin - multiple levels - mixed-model - bovine-milk - casein - yield
    Our objective was to perform a genome-wide association study for content in bovine milk of aS1-casein (aS1-CN), aS2-casein (aS2-CN), ß-casein (ß-CN), ¿-casein (¿-CN), a-lactalbumin (a-LA), ß-lactoglobulin (ß-LG), casein index, protein percentage, and protein yield using a 50K single nucleotide polymorphism (SNP) chip. In total, 1,713 Dutch Holstein-Friesian cows were genotyped for 50,228 SNP and a 2-step association study was performed. The first step involved a general linear model and the second step used a mixed model accounting for all family relationships. Associations with milk protein content and composition were detected on 20 bovine autosomes. The main genomic regions associated with milk protein composition or protein percentage were found on chromosomes 5, 6, 11, and 14. The number of chromosomal regions showing significant (false discovery rate
    Genome-wide association of milk fatty acids in Dutch dairy cattle
    Bouwman, A.C. ; Bovenhuis, H. ; Visker, M.H.P.W. ; Arendonk, J.A.M. van - \ 2011
    BMC Genetics 12 (2011). - ISSN 1471-2156 - 12 p.
    quantitative trait loci - stearoyl-coa desaturase - japanese black cattle - bovine-milk - genetic-parameters - holstein cattle - missense mutation - f-2 population - adipose fat - abcg2 gene
    Background Identifying genomic regions, and preferably individual genes, responsible for genetic variation in milk fat composition of bovine milk will enhance the understanding of biological pathways involved in fatty acid synthesis and may point to opportunities for changing milk fat composition via selective breeding. An association study of 50,000 single nucleotide polymorphisms (SNPs) was performed for even-chain saturated fatty acids (C4:0-C18:0), even-chain monounsaturated fatty acids (C10:1-C18:1), and the polyunsaturated C18:2cis9,trans11 (CLA) to identify genomic regions associated with individual fatty acids in bovine milk. Results The two-step single SNP association analysis found a total of 54 regions on 29 chromosomes that were significantly associated with one or more fatty acids. Bos taurus autosomes (BTA) 14, 19, and 26 showed highly significant associations with seven to ten traits, explaining a relatively large percentage of the total additive genetic variation. Many additional regions were significantly associated with the fatty acids. Some of the regions harbor genes that are known to be involved in fat synthesis or were previously identified as underlying quantitative trait loci for fat yield or content, such as ABCG2 and PPARGC1A on BTA 6; ACSS2 on BTA 13; DGAT1 on BTA 14; ACLY, SREBF1, STAT5A, GH, and FASN on BTA 19; SCD1 on BTA26; and AGPAT6 on BTA 27. Conclusions Medium chain and unsaturated fatty acids are strongly influenced by polymorphisms in DGAT1 and SCD1. Other regions also showed significant associations with the fatty acids studied. These additional regions explain a relatively small percentage of the total additive genetic variance, but they are relevant to the total genetic merit of an individual and in unraveling the genetic background of milk fat composition. Regions identified in this study can be fine mapped to find causal mutations. The results also create opportunities for changing milk fat composition through breeding by selecting individuals based on their genetic merit for milk fat composition.
    Genetic parameters for milk coagulation properties in Estonian Holstein cows.
    Vallas, M. ; Bovenhuis, H. ; Kaart, T. ; Parna, K. ; Kiiman, H. - \ 2010
    Journal of Dairy Science 93 (2010)8. - ISSN 0022-0302 - p. 3789 - 3796.
    cheese-making properties - finnish ayrshire cows - somatic-cell count - bovine-milk - chemical-composition - renneting properties - production traits - dairy-cows - physicochemical properties - protein-composition
    The objective of this study was to estimate heritabilities and repeatabilities for milk coagulation traits [milk coagulation time (RCT) and curd firmness (E30)] and genetic and phenotypic correlations between milk yield and composition traits (milk fat percentage and protein percentage, urea, somatic cell count, pH) in first-lactation Estonian Holstein dairy cattle. A total of 17,577 test-day records from 4,191 Estonian Holstein cows in 73 herds across the country were collected during routine milk recordings. Measurements of RCT and E30 determined with the Optigraph (Ysebaert, Frepillon, France) are based on an optical signal in the near-infrared region. The cows had at least 3 measurements taken during the period from April 2005 to January 2009. Data were analyzed using a repeatability animal model. There was substantial variation in milk coagulation traits with a coefficient of variation of 27% for E30 and 9% for the log-transformed RCT. The percentage of variation explained by herd was 3% for E30 and 4% for RCT, suggesting that milk coagulation traits are not strongly affected by herd conditions (e.g., feeding). Heritability was 0.28 for RCT and 0.41 for E30, and repeatability estimates were 0.45 and 0.50, respectively. Genetic correlation between both milk coagulation traits was negligible, suggesting that RCT and E30 have genetically different foundations. Milk coagulation time had a moderately high positive genetic (0.69) and phenotypic (0.61) correlation with milk pH indicating that a high pH is related to a less favorable RCT. Curd firmness had a moderate positive genetic (0.48) and phenotypic (0.45) correlation with the protein percentage. Therefore, a high protein percentage is associated with favorable curd firmness. All reported genetic parameters were statistically significantly different from zero. Additional univariate random regression analysis for milk coagulation traits yielded slightly higher average heritabilities of 0.38 and 0.47 for RCT and E30 compared with the heritabilities of the repeatability model.
    Genetic variation of natural antibodies in milk of Dutch Holstein-Friesian cows
    Ploegaert, T.C.W. ; Wijga, S. ; Tijhaar, E. ; Poel, J.J. van der; Lam, T.J.G.M. ; Savelkoul, H.F.J. ; Parmentier, H.K. ; Arendonk, J.A.M. van - \ 2010
    Journal of Dairy Science 93 (2010)11. - ISSN 0022-0302 - p. 5467 - 5473.
    humoral immune competence - production traits - lactoferrin content - urea nitrogen - laying hens - bovine-milk - parameters - autoantibodies - responses - paratuberculosis
    Defense mechanisms of dairy cows against diseases partly rest on their naturally present disease resistance capacity. Natural antibodies (NAb) form a soluble part of the innate immune system, being defined as antibodies circulating in animals without prior intentional antigenic stimulation. Genetic selection on NAb titers in milk, therefore, might improve disease resistance. We estimated genetic parameters of NAb titers binding lipopolysaccharide, lipoteichoic acid (LTA), peptidoglycan, and keyhole limpet hemocyanin, and titers of the NAb isotypes IgG1, IgM, and IgA binding LTA in milk of Dutch Holstein-Friesian heifers. Natural antibody titers were measured in 1 milk sample from each of 1,939 Holstein-Friesian heifers and used for estimating genetic parameters of NAb titers. The data show that phenotypic variation exists among heifers in NAb titers binding lipopolysaccharide, LTA, peptidoglycan, and keyhole limpet hemocyanin, and the NAb isotypes IgG1, IgM, and IgA binding LTA in milk. High genetic correlations among NAb (ranging from 0.45 to 0.99) indicated a common genetic basis for the levels of different NAb in bovine milk. Intra-herd heritability estimates for NAb ranged from 0.10 to 0.53. The results indicated that NAb levels have potential for genetic selection
    Genome-wide scan to detect quantitative trait loci for milk urea nitrogen in Dutch Holstein Friesian cows
    Bouwman, A.C. ; Schopen, G.C.B. ; Visker, M.H.P.W. ; Bovenhuis, H. ; Arendonk, J.A.M. van - \ 2010
    Journal of Dairy Science 93 (2010)7. - ISSN 0022-0302 - p. 3310 - 3319.
    finnish ayrshire cattle - somatic-cell score - dairy-cattle - genetic-parameters - health traits - fatty-acids - bovine-milk - nonprotein nitrogen - fertility traits - productive life
    Studies have reported genetic variation in milk urea nitrogen (MUN) between cows, suggesting genetic differences in nitrogen efficiency between cows. In this paper, the results of a genome-wide scan to identify quantitative trait loci (QTL) that contribute to genetic variation in MUN and MUN yield are presented. Two to 3 morning milk samples were taken from 1,926 cows, resulting in 5,502 test-day records. Test-day records were corrected for systematic environmental effects using a repeatability animal model. Averages of corrected phenotypes of 849 cows, belonging to 7 sire families, were used in an across-family multimarker regression approach to detect QTL. Animals were successfully genotyped for 1,341 single nucleotide polymorphisms. The QTL analysis resulted in 4 chromosomal regions with suggestive QTL: Bos taurus autosomes (BTA) 1, 6, 21, and 23. On BTA 1, 2 suggestive QTL affecting MUN were detected at 60 and 140 cM. On BTA 6, 1 suggestive QTL affecting both MUN and MUN yield was detected at 103 cM. On BTA 21, 1 suggestive QTL affecting MUN yield was detected at 83 cM. On BTA 23, 1 suggestive QTL affecting MUN was detected at 54 cM. Quantitative trait loci for MUN and MUN yield were suggestive and each explained between 2 and 3% of the phenotypic variance.
    Relationships between milk protein composition, milk protein variants, and cow fertility traits in Dutch Holstein-Friesian cattle
    Demeter, R.M. ; Markiewicz, K. ; Arendonk, J.A.M. van; Bovenhuis, H. - \ 2010
    Journal of Dairy Science 93 (2010)11. - ISSN 0022-0302 - p. 5495 - 5502.
    dairy-cows - reproductive-performance - bovine-milk - liquid-chromatography - genetic-parameters - yield - quantification - polymorphisms - associations - lactation
    Selective breeding can change milk protein composition to improve the manufacturing properties of milk. However, the effects of such breeding strategies on other economically important traits should be investigated before implementation. The objectives of this study were to examine the association between cow fertility traits and (1) milk protein composition and (2) milk protein variants (ß-lactoglobulin, ß-casein, ¿-casein, and ß-¿-casein) in commercial Dutch Holstein-Friesian cattle. Data on 1,644 first-lactation cows were analyzed by fitting linear mixed models. Greater relative concentration of aS1-casein within total milk protein had a positive phenotypic relationship with nonreturn rates and calving rate after first insemination. Furthermore, results showed virtually no significant relationship between cow fertility and concentration of other milk proteins or milk protein variants. Results of this study can be used to assess the correlated effects of breeding for improved milk protein composition on reproduction, thereby allowing for better evaluation of breeding programs before implementation. Our findings suggest that selecting cows based on milk protein composition or milk protein variants for improved manufacturing properties would have no negative influence on reproductive performance.
    Quantitative analysis of penicillins in porcine tissues, milk and animal feed using derivatisation with piperidine and stable isotope dilution liquid chromatography tandem mass spectrometry
    Holthoon, F.L. van; Mulder, P.P.J. ; Bennekom, E.O. van; Heskamp, H.H. ; Zuidema, T. ; Rhijn, J.A. van - \ 2010
    Analytical and Bioanalytical Chemistry 396 (2010)8. - ISSN 1618-2642 - p. 3027 - 3040.
    beta-lactam antibiotics - solid-phase extraction - bovine-milk - precolumn derivatization - antimicrobial residues - degradation-products - confirmatory assay - kidney - muscle - amoxicillin
    Penicillins are used universally in both human and veterinary medicine. The European Union (EU) has established maximum residue levels (MRLs) for most ß-lactam antibiotics in milk and animal tissues and included them in the National Residue Monitoring Programs. In this study, a novel method is described for the determination and confirmation of eight penicillins in porcine tissues, milk and animal feed by liquid chromatography–tandem mass spectrometry (LC–MS/MS). To prevent degradation of penicillin residues during workup, a derivatisation procedure was developed, by which penicillins were converted to stable piperidine derivatives. Deuterated piperidine derivatives were synthesised for all relevant penicillins, enabling the use of isotope dilution for accurate quantification. Penicillin residues were derivatised in the crude extract with piperidine and isolated using solid-phase extraction. The penicillin piperidine derivatives were determined by LC–MS/MS. The method was validated at the current MRLs, which range from 25–300 µg kg-1 in muscle and kidney to 4–30 µg kg-1 in milk as well as at the target value of 100 µg kg-1 chosen for animal feed, according to the EU requirements for a quantitative confirmatory method. Accuracy ranged from 94–113% (muscle), 83–111% (kidney) and 87–103% (milk) to 88–116% (animal feed). Intra-day precision (relative standard deviation (RSD)r) ranged from 5–13% (muscle, n¿=¿18), 4–17% (kidney, n¿=¿7) and 5–18% (milk, n¿=¿7) to 11–32% (animal feed, n¿=¿18). Inter-day precision (RSDRL, n¿=¿18) ranged from 6–23% (muscle) to 11–36% (animal feed). From the results, it was concluded that the method was fit for purpose at the target MRLs in animal tissue and target levels for animal feed
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