712 research outputs found

    Site of infusion of a commercially available direct-fed microbial on performance and digestibility in lactating Holstein cows

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    Objective: The objective of this research was to evaluate site of infusion of a commercially available direct-fed microbial (DFM) containing 109 cfu/g of Lactobacillus acidophilus and 109 cfu/g Propionibacterium freudenreichii on DMI, rumen kinetics, ruminal VFA, digestibility, milk production, milk components, and blood metabolites in lactating dairy cows. Materials and Methods: Four Holstein cows equipped with ruminal cannulas were used in a Latin square design experiment with 4 periods. Each 37-d period consisted of 14 d of no treatment to prevent crossover contamination, 14 d of adaptation to treatments, 8 d of sampling, and 1 d for ruminal evacuations. Within each period, cows were assigned to 1 of 4 treatments: (1) cows were fed a TMR formulated to meet or exceed nutrient requirements plus 5 g of lactose twice daily without the addition of DFM (control); (2) cows were fed the TMR with a daily dose of DFM top dressed on the feed twice daily (TD); (3) cows were fed the TMR with ruminal infusion of the DFM administered twice daily (RuI); or (4) cows were fed the TMR plus abomasal infusion of the DFM twice daily (AbI). During the sampling period within each period, DMI and milk production were measured daily with set days for blood and rumen fluid collection. Data were analyzed using the MIXED procedure of SAS with animal within period as a random effect. Dry matter intake was not different among treatments. Results and Discussion: No differences were detected in rumen kinetics, pH, individual VFA or VFA ratios, ammonia, or digestibility. There were no differences in kilograms of milk production (P \u3e 0.87); SCC (P \u3e 0.54); or percentage of butter fat (P \u3e 0.21), milk protein (P \u3e 0.83), lactose (P \u3e 0.91), SNF (P \u3e 0.88), and MUN (P\u3e 0.49). No difference existed in most of the milk fatty acids except for 8:0, which had a greater concentration (P \u3e 0.01) in AbI versus control, TD, and RuI. Implications and Applications: Route of administering DFM overall had no effects on DMI, rumen kinetics, ruminal VFA, digestibility, milk production, or milk components in the present experiment

    Water Intake in Growing Beef Cattle

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    Water is an essential part of livestock and human diets and is often thought of as an inexpensive, readily available renewable natural resource. However, the amount of competition between humans, wildlife, feed production, and livestock for high-quality water is increasing, not only from the effects of drought but from the pressure of a growing global population (Nardone et al., 2010). With limited resources available for production agriculture, there is a need to identify and select for efficient animals that can produce more product with fewer inputs. Although some work has been done in dairy cattle, very little data is available on individual animal water intake in modern beef cattle (Brew et al., 2011). The majority of the water intake data available in growing beef cattle is derived from dividing the total amount of water drunk in a pen divided by the number of animals in that pen (Sexson et al., 2010; Mader and Davis, 2004). Data derived from groups are not generally useful for the purposes of genetic evaluation, which aims to quantify individual animal variation in a trait for selection. However, in order to practice selection on a large scale, parameters for collecting phenotypic data must be established. The objectives of this study were to measure daily water intake on a large number of beef steers and to estimate the number of test days necessary to collect accurate water intake phenotypes

    Feeding wet distillers grains plus solubles with and without a direct-fed microbial to determine performance, carcass characteristics, and fecal shedding of Escherichia coli O157:H7 in feedlot heifers

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    Citation: Wilson, B. K., Holland, B. P., Step, D. L., Jacob, M. E., VanOverbeke, D. L., Richards, C. J., . . . Krehbiel, C. R. (2016). Feeding wet distillers grains plus solubles with and without a direct-fed microbial to determine performance, carcass characteristics, and fecal shedding of Escherichia coli O157:H7 in feedlot heifers. Journal of Animal Science, 94(1), 297-305. doi:10.2527/jas2015-9601The inclusion of wet distillers grains plus solubles (WDGS) in feedlot diets has become a common practice in many regions of the United States due to the expanded production of byproducts and fluctuating corn prices related to ethanol production and other factors. In addition, societal concerns over the continued use of antimicrobials in agriculture production combined with an enhanced interest in disease and pathogen prevention in the food supply have led to an increased interest in use of direct-fed microbials (DFM) in growing and finishing cattle. Direct-fed microbials have been shown to improve ADG and feed efficiency, alter ruminal fermentation, and decrease fecal shedding of potential harmful pathogens in feedlot cattle in some experiments. The objective of this experiment was to evaluate the effects of WDGS inclusion with or without a DFM containing Lactobacillus acidophilus (1 x 10(6) cfu . heifer(-1) . d(-1)) combined with Propionibacterium freudenreichii (1 x 10(9) cfu , heifer(-1) . d(-1)) on the performance, carcass characteristics, and Escherichia coli O157:H7 shedding in feedlot heifers. In early August, 288 crossbred heifers (initial BW = 295 +/- 28 kg) were assigned to 1 of 4 treatments (12 pens per treatment; 6 heifers per pen) in a randomized complete block design with a 2 x 2 factorial arrangement of treatments. Body weights and fecal grab samples were obtained at approximately 28-d intervals throughout the experiment. Across the feeding period, heifers fed 30% WDGS tended (P = 0.09) to have greater ADG and had greater carcass-adjusted ADG (P = 0.05) compared with heifers fed dry-rolled corn (DRC). Dry matter intake was not affected (P = 0.65) by diet, although carcass-adjusted G:F tended (P = 0.10) to be improved for heifers fed WDGS. Heifers fed 30% WDGS tended (P 0.10) on performance or carcass merit in the present experiment. The incidence of E. coli O157:H7 throughout the experiment was low, with only 18 positive samples across all sampling periods. Neither WDGS inclusion nor the inclusion of L. acidophilus combined with P. freudenreichii in the diet had any effect (P > 0.10) on E. coli O157:H7 shedding in this experiment. Feeding 30% WDGS to feedlot heifers improved animal performance compared to the DRC-based control diet

    Quantum Key Distribution using Deterministic Single-Photon Sources over a Field-Installed Fibre Link

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    Quantum-dot-based single-photon sources are key assets for quantum information technology, supplying on-demand scalable quantum resources for computing and communication. However, longlasting issues such as limited long-term stability and source brightness have traditionally impeded their adoption in real-world applications. Here, we realize a quantum key distribution field trial using true single photons across an 18-km-long dark fibre, located in the Copenhagen metropolitan area, using an optimized, state-of-the-art, quantum-dot single-photon source frequency-converted to the telecom wavelength. A secret key generation rate of 2 kbits/s realized over a 9.6 dB channel loss is achieved with a polarization-encoded BB84 scheme, showing remarkable stability for more than 24 hours of continuous operation. Our results highlight the maturity of deterministic single-photon source technology while paving the way for advanced single-photon-based communication protocols, including fully device-independent quantum key distribution, towards the goal of a quantum internet.Comment: 9 pages, 4 figure

    Effects of fat and/or methionine hydroxy analog added to a molasses-urea-based supplement on ruminal and postruminal digestion and duodenal flow of nutrients in beef steers consuming low-quality lovegrass hay

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    Five crossbred beef steers (initial BW = 338.6 ± 7.8 kg) fitted with ruminal and duodenal cannulas were used in a 5 × 5 Latin square design experiment to evaluate the effects of methionine hydroxy analog (MHA) and/or yellow grease (fat) added to a molassesurea- based supplement on intake and characteristics of digestion. Steers were fed low-quality hay (long-stem lovegrass Eragrostis curvula: 3.3% CP, 76.8% NDF; DM basis) ad libitum and supplemented with 0.91 kg/d (as fed) of 1 of 4 supplements in a 2 × 2 + 1 factorial arrangement of treatments. Supplemental treatments were 1) control (no supplement, NC); 2) molassesurea liquid supplement (U); 3) U containing (as-fed basis) 1.65% MHA (UM); 4) U containing (as-fed basis) 12% fat (UF); and 5) U containing (as-fed basis) 1.65% MHA and 12% fat (UMF). Total and forage OM intake (kg/d and as % of BW) increased (P \u3c 0.01) with molasses-urea, decreased (P ≤ 0.04) with MHA, and were not affected (P = 0.61) with fat supplementation. Total tract NDF digestibility increased (P = 0.01) with molasses-urea supplementation, and was less (P = 0.01) for fat than for nonfat supplementation. Total and microbial N flowing to the duodenum increased (P = 0.01) with molasses-urea supplementation. Although, total N flowing to duodenum was not affected (P = 0.27), microbial N decreased (P = 0.01), and nonammonia nonmicrobial N (NANMN) increased (P = 0.01) with fat supplementation. Extent of in situ OM and NDF digestibility at 96 h increased (P = 0.01) with molasses-urea supplementation, but were not affected (P ≥ 0.14) by either MHA or fat supplementation. Duodenal flow of total AA, essential AA, and nonessential AA increased (P ≤ 0.02) with molasses-urea supplementation. Total and nonessential serum AA concentration decreased (P \u3c 0.01) with molasses-urea supplementation. Total ruminal VFA concentration increased (P = 0.01) with molasses-urea supplementation, and was not affected (P ≥ 0.14) by MHA or fat supplementation. Fat can be used in molasses-urea liquid supplements for cattle consuming low-quality forage to increase energy intake without negatively affecting forage intake or characteristics of digestion. However, adding MHA did not further improve the response to urea supplementation of cattle consuming low-quality forage. Conversely, the inclusion of MHA on urea supplement decreased forage intake

    Development of the iCook 4-H Curriculum for Youth and Adults: Cooking, Eating, and Playing Together for Childhood Obesity Prevention

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    The objective was to describe the development process of a curriculum (iCook 4-H) targeted to low-income, rural, and/or diverse youths and their adult primary meal preparer to promote cooking, eating, and playing together. Lessons learned highlighted the importance of grounding the curriculum in Social Cognitive Theory and applying the experiential 4-H learning model using a multiphased, community-based participatory approach with cyclical development and evaluation, and key modifications made for dissemination and distribution. Findings across 4 testing phases over 6 years and 5 states demonstrated the time-intensive, cyclical process that required flexibility with fidelity to form a hands-on, interactive curriculum

    Timing Calibration and Windowing Technique Comparison for Lightning Mapping Arrays

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    Since their introduction 22 years ago, lightning mapping arrays (LMA) have played a central role in the investigation of lightning physics. Even in recent years with the proliferation of digital interferometers and the introduction of the LOw Frequency ARray (LOFAR) radio telescope, LMAs still play an important role in lightning science. LMA networks use a simple windowing technique that records the highest pulse in either 80 μs or 10 μs fixed windows in order to apply a time-of-arrival location technique. In this work, we develop an LMA-emulator that uses lightning data recorded by LOFAR to simulate an LMA, and we use it to test three new styles of pulse windowing. We show that they produce very similar results as the more traditional LMA windowing, implying that LMA lightning mapping results are relatively independent of windowing technique. In addition, each LMA station has its GPS-conditioned clock. While the timing accuracy of GPS receivers has improved significantly over the years, they still significantly limit the timing measurements of the LMA. Recently, new time-of-arrival techniques have been introduced that can be used to self-calibrate systematic offsets between different receiving stations. Applying this calibration technique to a set of data with 32 ns uncertainty, observed by the Colorado LMA, improves the timing uncertainty to 19 ns. This technique is not limited to LMAs and could be used to help calibrate future multi-station lightning interferometers

    Determining Electric Fields in Thunderclouds With the Radiotelescope LOFAR

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    An analysis is presented of electric fields in thunderclouds using a recently proposed method based on measuring radio emission from extensive air shower events during thunderstorm conditions. This method can be regarded as a tomography of thunderclouds using cosmic rays as probes. The data cover the period from December 2011 till August 2014. We have developed an improved fitting procedure to be able to analyze the data. Our measurements show evidence for the main negative-charge layer near the −10° isotherm. This we have seen for a winter as well as for a summer cloud where multiple events pass through the same cloud and also the vertical component of the electric field could be reconstructed. On the day of measurement of some cosmic-ray events showing evidence for strong fields, no lightning activity was detected within 100 km distance. For the winter events, the top heights were between 5 and 6 km, while in the summer, typical top heights of 9 km were seen. Large horizontal components in excess of 70 kV/m of the electric fields are observed in the middle and top layers
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