1,720,989 research outputs found
Impact of dietary lipid source on fecal microbiota composition in dairy cows
No full textThe degree of saturation of the dietary lipid sources could affect the microbiota of the animal digestive tract. Aim of this experiment was to evaluate the influence of two different lipid sources, one saturated (hydrogenated fatty-Megafat 88; FAT), and one unsaturated (soybean full-fat flaked; SOY) on fecal microbiota composition of high-producing dairy cows fed hay – based ration. The study involved 8 Italian Friesian dairy cows and pH, rumination time, rumen and feces microbiota composition (bacteria and
protozoa) were determined. DNA from rumen contents was extracted, purified, and sequenced to quantify bacteria populations. Sequencing was performed on Illumina MiSeq. Data were analyzed with JMP pro v 17.1. For the statistical analysis, a linear mixed model was used with a fixed effect: Saturated Fat vs Unsaturated fat. The different lipid sources significantly influenced bacteria community in feces. Ruminococcaceae family showed a tendency (p=0.06) being higher in FAT compared to SOY (27.9% vs. 24.5%), while Peptostreptococcaceae were higher in SOY compared to FAT (3% vs. 1.95%). Rikenellaceae were significantly higher in SOY (21.8% vs 19.7%), while Prevotellaceae did not differ, as well as Fibrobacteriaceae, Lachnospiraceae, Christensellaceae and Veilonellaceae. Moreover, within the same treatment group, the cited families were significantly different
among animals for both SOY and FAT, with the exception of Rikenellaceae, which did not differ in SOY treatment. Since this part of the study followed a similar analysis of the rumen microbiota of the same animals, it was possible to observe substantial differences among the two. Surprisingly, Proevotellaceae, the most abundant family in the rumen, showed a decreased abundance (11% on average), while Rikenellaceae, which are not so represented in the rumen, increased their relative abundance in
feces. Ruminococcaceae were more abundant in feces compared to the rumen, and even the family composition, in terms of genera, was different. In conclusion, the lipid source affected fecal microbiota, showing differences in families that are not abundant in the rumen, but highly represented in the intestinal tract of different mammalian species, including cows, buffaloes, and humans. At the same time, data underlined the individual response even when animals are fed the same lipid source, and the unicity of the intestinal environment compared to the ruminal one
Assessment of individual dairy cows in vitro rumen methane emissions
No full textResearch in the last years has resulted in a better understanding of factors influencing methane (CH4) emissions, the main greenhouse gas produced by ruminants. A large proportion of the variation in enteric CH4 emissions from animals can be explained by diet composition and feed intake. Nevertheless, differences in CH4 release might be ascribed to each individual cow. Aim of the study was to screen the CH4 production in individual dairy cows using the Gas Endeavour® in vitro system (GE, Bioprocess Control, Svezia). For this purpose, 58 Italian Friesian dairy cows from the University of Bologna dairy research farm were enrolled. Animals had, on average, 3.5 years of age (±1.36), 176.5 DIM (±110.52), 40l/day milk yield (±11.79), 3.92% fat (±0.43), 3.45% protein (±0.23). Diet fed to all animals was mainly composed by alfalfa hay (35.1%DM), wheat hay (11.16%DM), and cereal mix (48%DM). Rumen fluid was sampled with an esophageal probe at 9.0 am after feeding. After collection, the rumen fluid was filtered with a sieve (1mm diameter pores) to eliminate gross material, and then measured for its pH using a pH meter (PH20er, VWR). The rumen fluid was thus used as inoculum for in vitro TMR fermentation, according to the Tilley and Terry (1963) modified technique. CH4 production was measured in vitro using the GE. CH4 production was evaluated at 3 different time points: 8 (T1), 12 (T2) and 24 (T3) hours of incubation. Data distributions were different per time point, as expected (170mL in T1, 204.4mL in T2, 228.8mL in T3, on average). In addition, we observed a significant correlation between CH4 production at T2 and T3 (r2=0.99, p <0.01). Rumen fluid pH was 6.13 (±0.38) on average, and positively correlated with CH4 production (r2=0.3, p=0.28). On the opposite, age (r2=−0.33, p=0.83) and milk yield (r2=−0.12, p=0.79) were negatively correlated. The result showed that cows with the same diet had different CH4 productions also in vitro. Differences between the groups remained constant for all fermentation time points evaluated. Interestingly, a high correlation of CH4 production was achieved between T2 and T3. In conclusion, these results indicated that 12h of fermentation are sufficient to have reliable data on CH4 production in vitro
Foraggi secchi e insilati: costi e benefici
Full text linkAllevatori, veterinari e tecnici nutrizionisti da tempo riconoscono nella disponibilità di foraggi di buona qualità il principale fattore alimentare responsabile di ottimali risultati sanitari e produttivi nelle stalle. Solo in parte sostituibili nelle razioni, i foraggi condizionano i processi digestivi e la capacità di ingestione degli animali e, in definitiva, le loro performance in stalla
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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