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Mid-infrared spectroscopy for an accurate prediction of immunoglobulins G concentration in bovine colostrum
No full textMid-infrared spectroscopy for a rapid assessment of immunoglobulins G level in bovine colostrum
No full textThe concentration of immunoglobulins G (IgG, g/l) defines colostrum quality in cattle. By convention, colostrum
with IgG<50 g/l is not recommended for calves feeding in the first h of life due to insufficient antibodies level. On
average, 15% of cows produce colostrum of unacceptable quality in dairy farms, exposing the calf to greater risk of
mortality and morbidity and impairing the future heifer’s performance. In this study, first colostrum samples (521
Holstein cows) were collected between 2019 and 2020 in 9 farms within 6 h from calving. Each sample was aliquoted
for IgG and protein content determination via gold standard, i.e. radial immunodiffusion and Kjeldahl, respectively,
and for prediction of total protein content via mid-infrared spectroscopy (MIR) using the prediction model developed
for mature milk. Before MIR analysis, colostrum samples were diluted in pure water (1:1) to reduce matrix density
and avoid clogging issues. We demonstrated that MIR-predicted protein content was significantly correlated with both
IgG (r=0.87) and protein content (r=0.97) measured with gold standard. Moreover, receiving operating characteristic
analysis (ROC) showed that MIR-predicted protein content was able to accurately identify low- from high-quality
colostrum samples regardless of the IgG threshold considered (50, 70, or 90 g/l). In parallel, we evaluated the
discriminant ability of colostral refractive index (BRIX), whose performance were similar to those of MIR-predicted
protein content. The area under the ROC curve was excellent, being 0.85 for MIR-predicted protein content and 0.83
for BRIX when IgG threshold was set at 50 g/l. The cut-off identified for MIR-predicted protein content was 13.08,
13.28, and 14.64% for IgG threshold at 50, 70, and 90 g/l, respectively. Findings do suggest that milk labs equipped
with MIR devices may offer an indirect quality evaluation of bovine colostrum for screening purposes and to support
farmers’ decision making. Finally, our results are of interest for industries that use bovine colostrum as an ingredient
Application of a handheld near-infrared spectrometer to predict gelatinized starch, fiber fractions, and mineral content of ground and intact extruded dry dog food
Full text linkThe aim of the present study was to investigate the ability of a handheld near-infrared spectrometer to predict total and gelatinized starch, insoluble fibrous fractions, and mineral content inextruded dry dog food. Intact and ground samples were compared to determine if the homogenization could improve the prediction performance of the instrument. Reference analyses were performed on 81 samples for starch and 99 for neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergentlignin (ADL), and minerals, and reflectance infrared spectra (740 to 1070 nm) were recorded with aSCiOTMnear-infrared (NIR) spectrometer. Prediction models were developed using modified partial least squares regression and both internal (leave-one-out cross-validation) and external validation.The best prediction models in cross-validation using ground samples were obtained for gelatinized starch (residual predictive deviation, RPD = 2.54) and total starch (RPD = 2.33), and S (RPD = 1.92), while the best using intact samples were obtained for gelatinized starch (RPD = 2.45), total starch (RPD = 2.08), and K (RPD = 1.98). Through external validation, the best statistics were obtained for gelatinized starch, with an RPD of 2.55 and 2.03 in ground and intact samples, respectively. Overall, there was no difference in prediction models accuracy using ground or intact samples. In conclusion, the miniaturized NIR instrument offers the potential for screening purposes only for total and gelatinized starch, S, and K, whereas the results do not support its applicability for the other traits
Genetic aspects of colostrum quality traits including immunoglobulin G in Holstein cows
Full text linkImmunoglobulins G (IgG), A (IgA), and M (IgM) account for 80% of total proteins in bovine colostrum and are important for the passive transfer of antibodies from the dam to the calf. The practical difficulties of samples collection and the high cost of gold standard analysis have so far hampered the estimation of genetic parameters of both bovine colostrum and mature milk IgG, IgA, and IgM concentrations (g/L). In the present study, 672 colostrum samples from the same number of Holstein cows were collected within 6 h after calving. The concentration of IgG, IgA, and IgM was determined through radial immunodiffusion. The pedigree included 6,714 animals, i.e., cows with phenotypes and up to 6 generations of ancestors. Linear models were used to estimate
variance and covariance components through univariate and bivariate analyses, respectively. The model included the random animal additive genetic effect and the fixed effects of parity (5 levels: 1, 2, 3, 4, and ≥5), season of calving (4 levels), year of calving (2 levels), and herd (9 levels). Colostrum IgG, IgA, and IgM averaged 93.24, 4.89, and 5.16 g/L, respectively, and were normally distributed. Heritabilities (±standard error) of IgG, IgA, and IgM were 0.14 ± 0.14, 0.33 ± 0.16, and 0.19 ± 0.14, with coefficients of genetic variation of 13.1, 30.8, and 19.7%, respectively. The IgG correlated phenotypically with IgA (0.52 ± 0.04) and IgM (0.59 ± 0.03), and IgA correlated with IgM (0.48 ± 0.04). Overall, genetic correlations were weak (<0.10) except for the association between IgG and IgA (0.37 ± 0.41). Results agreed with the literature and highlighted that the most important colostrum quality trait, i.e., the IgG, tended to be the least heritable Ig. Further efforts will allow to improve data size and variability and will be focused on coupling Ig data with other information to estimate the association between Ig of the colostrum administered to the calf and health and productivity in the subsequent lactations
Genetic aspects of immunoglobulins G concentration measured with gold standard and predicted from infrared spectra in bovine colostrum
Full text linkThe concentration of immunoglobulins G (IgG) is the criterion usually adopted to classify the quality of the colostrum adminis-tered to calves. Although the reference analysis of IgG (g/L) is time-consuming and expensive, no studies have evaluated the ability of infrared spectroscopy to predict colostrum IgG concentration so far. In this study, colostrum was collected on 693 Holsteins within 6 h after calving following a specific protocol. Samples were analysed through the reference analysis (radial immunodiffusion), which was carried out according to the manufacturer’s instructions (Triple J Farm, Bellingham, US) after dilution of colostrum (1:5 v/v) in pure water. Near-infrared spectra (400–2500 nm) were collected on all samples using the DS2500 (Foss, Hillerød, Denmark). After spectra quality editing, the final dataset accounted for 685 samples. The calibration set included 195 samples representative of the 9 herds and cows from parity 1 to 6, and the best prediction model for IgG (RMSE =14.2 g/L; R2 = 0.84) was reached through 20-fold cross-validation and multiplicative scatter correction and second derivative as mathematical treatment. Finally, IgG was predicted in the validation set which accounted for the remaining 490 samples (RMSE =19.4 g/L; R2 = 0.73). Variance and covariance components were estimated for both reference and predicted IgG (validation set) using a linear model which included the fixed effects of parity (5 levels: 1, 2, 3, 4, and 5 + 6), the season of calving (4 levels), year of calving (2 levels), and herd (9 levels), and the random effects of additive genetic animal (6714 individuals in the pedigree) and the residual. Means (coefficient of genetic variation) of reference and predicted IgG were 92.4 g/L (14.8%) and 90.5 g/L (15.1%), respectively. Heritabilities of IgG were 0.18 ± 0.15 (reference) and 0.21 ± 0.15 (predicted). The phenotypic correlation between the two traits was positive and strong (0.86 ± 0.01), as well as the genetic correlation (0.99 ± 0.11). Overall, results indicated that IgG can be predicted from colostrum spectra with moderate accuracy and the genetic correlation between the reference and predicted IgG is close to 1. Therefore, IgG predictions can be potentially exploited as phenotypes to improve the IgG content of bovine colostrum, leading to potential practical positive consequences on calf health
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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