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Effects of Replacing Forage Fiber with non-Forage Fiber in Lactating Dairy Cow Diets
No full textEight primiparous and eight multiparous lactating Holstein cows were used in a replicated 4 x 4 Latin square design to evaluate the effect of replacing forage fiber with non-forage fiber source on the performance of the dairy cows. Four diets were formulated to replace corn silage with dried corn distillers grains with solubles (DDG) at 0, 7, 14, and 21 % (DM basis). The control diet contained 40% corn silage, 15% alfalfa hay, and 45% concentrate (DM basis). Soybean meal was replaced with soybean hulls as the percentage of DDG increased in the diets. Alfalfa hay was equal for all diets. Replacing corn silage with DDG increased the proportion of feed particles, as fed basis, passing through the 1.18 mm sieve of the Penn State Particle separator. Dry matter intake increased with increasing concentrations of DDG in the diet. Total NDF and non-forage NDF in the diets were increased while forage NDF was decreased significantly as DDG replaced corn silage in the diet. Milk protein percentage, protein yield, milk lactose percentage and lactose yields were increased. Milk fat percentage, fat yield and feed efficiency were decreased as the percentage of DDG increased in the diets. Milk yield, energy-corrected milk and milk urea nitrogen were not altered because of diet. As a result, molar proportion of ruminal acetate decreased and propionate increased as DDG increased in the diet. Replacing forage fiber with non-forage fiber in lactating dairy cow diets increased DMI and decreased milk fat percentage and did not change fat-corrected milk yield. Dried com distillers grains with solubles did not provide necessary effective fiber to maintain normal milk fat production. When formulating diets with DDG, it is critical that sufficient effective fiber is included in the diet to prevent milk fat depression
Lowering ruminally degradable protein in lacatating dairy cow diets
No full textLactating dairy cows convert 25 to 35% of intake N to milk N, and a part of the remaining N ends up in the environment, causing pollution. Dairy cows absorb amino acids available in the small intestine supplied mainly by digestion of microbial protein and ruminally undegraded feed protein (RUP). Ruminally degradable feed protein (RDP) is the major supplier of N for microbial protein synthesis. Most of the excess RDP will be degraded to ammonia and eliminated as urea in urine. Thus, avoiding excess RDP in dairy cattle diets is important in reducing environmental N pollution. The objectives of the work in this dissertation were to test the hypothesis that lactating dairy cows, when fed varying dietary RDP, can maintain feed intake, milk and milk protein yield, ruminal metabolism, passage of nutrients out of the rumen, and N excretion.
The first study investigated the effects of decreasing RDP in lactating dairy cow diets on feed intake, milk production and apparent N efficiency. Forty mid-lactation cows (36 Holstein and 4 Jersey × Holstein cross-breds) were fed a diet containing 11.3% of diet dry matter (DM) as RDP for the first 28 d (covariate period). From d 29 to 47 (treatment period) cows were randomly assigned to 1 of 4 diets containing constant RUP (7.1% of DM) but 11.3, 10.1, 8.8, or 7.6% of DM as RDP. Reducing RDP in diets linearly decreased DM intake and tended to decrease milk yield. Milk protein, fat and lactose contents, milk protein yield, body weight, and plasma essential amino acids were unaffected by reduced dietary RDP. However, milk urea-N concentration and milk fat yield decreased linearly with reduced dietary RDP. The apparent efficiency of N utilization for milk N production increased linearly as dietary RDP was reduced. As RDP declined in diets, linear reductions in DM intake and milk production suggested that these cannot be maintained below NRC recommendations of RDP for cows in this study.
The aim of the second study was to test the hypothesis that decreasing dietary RDP in lactating dairy cow diets can maintain ruminal metabolism and flow of nutrients out of the rumen and reduce nitrogen excretion. This study was designed as a replicated Latin square with 4 periods of 21 d each. Four treatment diets containing decreasing RDP and constant RUP similar to the first study were used. Three ruminally and duodenally cannulated and 4 ruminally cannulated lactating Holstein cows were randomly assigned to one of the four dietary treatments. A double marker system with Co-EDTA and Yb-labeled forage as markers was used to determine ruminal outflows of nutrients from omasal samples and nutrients reaching the intestine from duodenal samples. Ruminal microbial protein flow was observed using ¹⁵N as an external microbial marker. Feed intake, milk yield, milk composition, and urine and feces output were determined in the last week of each period. Ruminal fluid samples were taken 2 and 4 h after feeding to determine ruminal NH₃-N and volatile fatty acid concentrations. Outflows of nutrients from the rumen were determined by analyzing omasal samples collected over a 24 h feeding cycle in the last week of each period. Reducing dietary RDP decreased protein intakes while DM and fiber intakes were unaffected. Ruminal NH₃-N concentrations linearly declined and peptides and amino acids were unaffected with reduced dietary RDP. A trend for a linear decline in ruminal outflows of microbial N and total N was observed with decreasing dietary RDP. Ruminal volatile fatty acids concentrations were unaltered by feeding treatment diets. Ruminal outflows of DM and acid detergent and neutral detergent fibers were unaffected by treatments. Treatment diets did not have any effect on milk yield and milk composition. However, milk urea-N and milk fat yield decreased linearly with decreasing dietary RDP. Reducing dietary RDP did not affect milk and milk protein yields but did result in greater body protein mobilization. Fecal N output was unaffected however, urine volume and urine N output decreased linearly suggesting reduced environmental N pollution. There was a trend for a linear decrease in total body N balance, but no significant effects on calculated ruminal N balance as dietary RDP decreased. Linear reductions in microbial N leaving the rumen were due to decreased ruminal NH₃-N as peptides plus amino acids and energy supply were unaffected. The linear reduction in milk production and microbial N flow in the first and second studies, respectively, did not support our hypothesis that lactating dairy cows can be fed dietary RDP below current NRC (2001) recommendations without affecting animal performance. The need to raise 15% more cows to alleviate the loss in production may nullify the advantage in reduced N output into the environment by cows fed lower dietary RDP.Ph. D
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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