1,721,054 research outputs found
Use of mid-infrared spectroscopy to predict milk technological traits in grazing Irish dairy cows
No full textPrediction of proteins including free amino acids in bovine milk by mid-infrared spectroscopy
No full textThe aim of this study was to evaluate the effectiveness of mid-infrared spectroscopy (MIRS) in predicting individual milk proteins and free amino acids in bovine milk and estimating their correlations with milk processing characteristics. A total of 730 milk samples were collected from seven Irish research herds and represented cows from a range of breeds, parities and stages of lactation. Gold-standard methods were used to quantify protein fractions and free amino acids (FAA) of these samples. Separate prediction equations were developed for each trait using partial least squares regression and accuracy of prediction was assessed using both cross validation and external validation. The greatest coefficient of correlation in external validation obtained for protein fractions was for total casein (0.74), while weak to moderate prediction accuracies were observed for FAA and among these glycine had the greatest coefficient of correlation (0.75 in both cross validation and external validation). Near unity correlations existed between total casein and beta-casein irrespective of whether the traits were based on the gold-standard (0.92) or MIRS predictions (0.95). Pearson correlations between gold-standard protein fractions and gold-standard milk processing characteristics ranged from -0.48 (pH and protein) to 0.50 (total casein and curd firmness). The lactation profile of total FAA indicated that the greatest concentration of FAA in milk was during early and late lactation. Results from this study demonstrate that mid-infrared spectroscopy has the potential to predict protein fractions and some FAA in milk
Genetics of protein fractions and free amino acids predicted by mid-infrared spectroscopy
No full textMilk protein fractions and free amino acids (FAA) are important traits for the dairy industry specialized in cheese and milk powder production. Despite this, they are not included in any breeding objective due to the lack of quick and cost-effective routine determination of these compounds. In the present study, mid-infrared spectroscopy prediction models previously developed on bovine milk samples in Ireland were applied to stored spectral data to predict both protein fractions and FAA concentrations. After edits, 134,546 test-day records from 16,166 lactations and 9,572 cows were available. Variance components were estimated using repeatability animal models including the fixed effects of contemporary group, milking time, cow breed proportion, general heterosis, recombination loss, and parity-by-stage of lactation. Random terms were additive genetic effect of the animal, and within- and across lactation permanent environmental effects. Means of αs1-casein, αs2-casein, β-casein, and κ-casein were 13.70 g/l, 3.66 g/l, 12.96 g/l, and 6.03 g/l, respectively. About 83% of total whey proteins (6.13 g/l) were represented by β-lactoglobulin. Concentrations of FAA exhibited average values that ranged from 8.09 μg/ml (glycine) to 1.52 μg/ ml (valine), except for glutamic acid (30.93 μg/ml). Heritability estimates for protein fractions ranged from 0.36 (αs2-casein and κ-casein) to 0.46 (β-lactoglobulin A), except for α-lactalbumin (0.19). The range of heritability estimates for FAA was smaller (0.15 for glycine to 0.36 for aspartic acid). Genetic correlations between casein fractions and whey proteins were all positive. Genetic correlations between FAA ranged from -0.44 (aspartic acid and lysine) to 0.97 (glutamic acid and total free amino acids). Breeding strategies for genetically improving protein fractions and FAA may represent a viable solution to meet the requirements of specialized dairy industry
Traits associated with protein composition and colour of bovine milk
No full textThe aim of this study was to determine the associations of parity, stage of lactation and milking time with protein composition and colour of bovine milk. Mid-infrared spectral (MIRS) data from 2013 to 2015, inclusive were obtained from the milk samples of 3 research herds. Spectral outliers were detected using mahalanobis distance and removed. Data were further edited to remove records from cows which were greater than 305 days in milk or were greater than tenth parity. Equations developed recently to predict individual protein fractions and milk colour directly from the MIR spectrum were applied to the data yielding 64,606 records from 1,102 Holstein-Friesian cow lactations of alpha s1, beta, and kappa casein as well as the yellowness of milk. Factors associated with each of the milk quality traits were quantified using linear mixed models. All models were adjusted for milking time, parity (1, 2, 3, 4 and 5+) and stage of lactation (5 equal groups of 60); and the random effects of within and across lactation permanent environmental effects and herd_year_season. Older animals had yellower milk with a higher level of kappa casein and lower level of beta casein (P<0.001). As lactation progressed, milk got yellower in colour (P<0.001) and had higher levels of kappa, beta and alpha s1 casein (P<0.001). Futhermore, although evening milk had a yellower colour than morning milk and higher levels of alpha s1 casein, there was no difference in beta casein across milking time, and the difference in kappa casein was small
Relationship among milk coagulation properties and milk protein composition in Italian and Irish dairy cows
No full textGenetics of milk coagulation properties predicted by milk mid infrared spectrometry analysis of Irish dairy cows
No full textMilk coagulation properties (MCP) are important traits for profitable dairying. To improve MCP through animal breeding large quantity of routinely available data on MCP as well as existence of heritable genetic variation in these traits is required. Objectives of this study were to i) develop prediction equations for MCP through mid-infrared spectroscopy (MIRS) ii) apply equations to a spectra dataset of Holstein-Friesian cows, and iii) estimate variance components. Data for MCP and MIRS were available on 324 samples. Proportion of variation in external validation for RCT, k20, and a30 explained by equations was 0.45, 0.41 and 0.27, respectively. Heritability for MCP estimated from 9,867 spectra on 1,104 cows varied from 0.06 to 0.20; coefficient of genetic variation for MCP varied from 5.99 to 10.07, while genetic correlations between MCP and milk quality traits demonstrated positive relationships between MCP and milk composition
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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