Evaluation of intake and feed efficiency measures in beef cattle

Four experiments were conducted to evaluate intake and measures of feed efficiency in beef cattle. In Exp. 1 and 2, measures of feed efficiency were calculated on Angus and SimAngus heifers (Exp.1; n = 623, and Exp. 2; 404); and heifers were classified as either high, medium, or low residual feed intake (RFI), residual BW gain (RG), residual intake and BW gain (RIG), and DMI. The objective of these experiments was to determine the relationship between post-weaning feed efficiency and intake in heifers, and subsequent cow performance, reproduction, and longevity as 2-and 5-yr-old cows. As heifer RFI improved, cow forage DMI was reduced in both 2-and 5-yr old cows (P < 0.01) and resulted in more desirable 2-yr old cow efficiency (P < 0.01). Heifer RFI classification did not affect (P ≥ 0.07) reproductive traits, cow production traits, or herd longevity up to 5 yr of age. Heifer RG classification did not affect (P ≥ 0.08) reproductive traits; cow production traits, cow efficiency, or DMI in 2-yr-old cows. As heifer RIG improved, 2-yr-old cow forage DMI was reduced (P < 0.01) during lactation, resulting in more desirable cow efficiency (P=0.02). Heifer RIG classification did not affect (P ≥ 0.12) reproductive traits; calf birth or weaning BW; cow BW, milk production, 12th rib fat thickness, or BCS in 2-yr old cows. Heifer DMI was highly correlated (P < 0.05) to cow forage intake as both 2- and 5-yr-old cows. Heifers classified as low DMI were least frequently (P < 0.01) kept as replacements and were youngest (P = 0.04) at first calving. Calves from 2-yr-old cows, classified as high DMI heifers, had the greatest (P < 0.01) birth BW; yet, there were no differences (P=0.60) in weaning BW. Intake classification had no effect (P ≥ 0.07) on cow BCS, 12th rib fat thickness, or milk production in either 2- or 5-yr-old cows. Cows, classified as low DMI heifers, weighed the least (P = 0.02) and had reduced (P < 0.01) hip heights as both 2- and 5-yr old cows. Cows, classified as low DMI heifers, had reduced (P ≤ 0.01) DMI, improved (P = 0.01) cow efficiency, and a greater percentage of females remaining in the herd at 5 yr of age. These data indicate that females classified as more efficient have reduced cow DMI without compromising production traits and longevity. Heifer DMI is an accurate predictor of cow forage intake at different biological time points in life. In Exp. 3, measures of feed efficiency were determined in Angus and Simmental X Angus heifers (n=263), and heifers were classified within feed intake and efficiency groups as described in Exp. 1 and 2. The objective of this experiment was to determine the relationship between measures of heifer feed efficiency and mature cow intake of forage of divergent quality. At 5 or 6-yr of age, cows were evaluated for voluntary forage intake of high-quality forage (HQDMI) and poor-quality forage (PQDMI). Heifer RFI classification had no effect on cow production traits; yet, cows classified with the least desirable heifer RFI had the greatest (P ≤ 0.05) HQDMI and PQDMI. Heifer RG classification had no effect on cow production traits or DMI. Heifer RIG classification had no effect on cow traits. Cows classified as low RIG heifers had the greatest (P = 0.02) HQDMI; yet, only tended to have the greatest PQDMI (P = 0.09). Cows classified as high DMI heifers were heavier (P = 0.05) and had greater (P < 0.01) DMI than cows classified as low or medium DMI heifers. This study suggests that feed costs can be reduced by selection for heifer RFI, RIG, and DMI. In Exp. 4, Charolais crossbred heifers and steers (n=628) endured two performance and intake tests during the growing and finishing phases of the feedlot phase. Objectives were to determine the effects of test period duration, timing, and diet type on measures of feed efficiency in feedlot calves. Dry matter intake and RFI were repeatable (r=0.56; P<0.01, and 0.63; P<0.01, respectively) for both periods of grain-fed steers. Average daily gain was not repeatable (r=0.11; P=0.06) across both test periods for steers. However, growing and finishing ADG were correlated (r=0.58; P<0.01, and r=0.69; P<0.01, respectively) to total feeding period ADG. Regardless of test length, from 7 to 70d, DMI was correlated (r≥0.87; P<0.01) to total DMI during the growing period. Heifer forage DMI was correlated (r=0.58; P<0.01) to grain DMI. Forage and grain RFI were moderately correlated (r=0.40; P<0.01) for heifers. These data indicate that DMI is repeatable across varying stages of maturity in cattle, and accurate feed efficiency measures can be obtained in either the growing or finishing period. The relationship of forage and grain DMI and efficiency in heifers suggests that measures of DMI and feed efficiency are relevant, regardless of diet fed. Intake evaluation periods can be shortened without losing accuracy in predicting individual animal DMI; and measures of feed efficiency can be calculated by decoupling performance and intake information. Collectively, these experiments provide insight into the effects of DMI and feed efficiency on many production traits; and the potential methods in which both feedlot and cow-calf producers can improve profitability within their operations

Challenges in conducting community-driven research created by differing ways of talking and thinking about science: a researcher&#x2019;s perspective

Increasingly, health scientists are becoming aware that research collaborations that include community partnerships can be an effective way to broaden the scope and enhance the impact of research aimed at improving public health. Such collaborations extend the reach of academic scientists by integrating a variety of perspectives and thus strengthening the applicability of the research. Communication challenges can arise, however, when attempting to address specific research questions in these collaborations. In particular, inconsistencies can exist between scientists and community members in the use and interpretation of words and other language features, particularly when conducting research with a biomedical component. Additional challenges arise from differing perceptions of the investigative process. There may be divergent perceptions about how research questions should and can be answered, and in expectations about requirements of research institutions and research timelines. From these differences, misunderstandings can occur about how the results will ultimately impact the community. These communication issues are particularly challenging when scientists and community members are from different ethnic and linguistic backgrounds that may widen the gap between ways of talking and thinking about science, further complicating the interactions and exchanges that are essential for effective joint research efforts. Community-driven research that aims to describe the burden of disease associated with Helicobacter pylori infection is currently underway in northern Aboriginal communities located in the Yukon and Northwest Territories, Canada, with the goal of identifying effective public health strategies for reducing health risks from this infection. This research links community representatives, faculty from various disciplines at the University of Alberta, as well as territorial health care practitioners and officials. This highly collaborative work will be used to illustrate, from a researcher&#x2019;s perspective, some of the challenges of conducting public health research in teams comprising members with varying backgrounds. The consequences of these challenges will be outlined, and potential solutions will be offered

Metastable Pluripotent States in NOD Mouse Derived ES Cells

Embryonic stem (ES) cells are isolated from the inner cell mass (ICM) of blastocysts, whereas epiblast stem cells (EpiSCs) are derived from the post-implantation epiblast and display a restricted developmental potential. Here we characterize pluripotent states in the non-obese diabetic (NOD) mouse strain, which prior to this study was considered “non-permissive” for ES cell derivation. We find that NOD stem cells can be stabilized by providing constitutive expression of Klf4 or c-Myc or small molecules that can replace these factors during in vitro reprogramming. The NOD ES and iPS cells appear “metastable”, as they acquire an alternative EpiSC-like identity after removal of the exogenous factors, while their reintroduction converts the cells back to ICM-like pluripotency. Our findings suggest that stem cells from different genetic backgrounds can assume distinct states of pluripotency in vitro, the stability of which is regulated by endogenous genetic determinants and can be modified by exogenous factors.National Institutes of Health (U.S.) (Grant RO1-HDO45022)National Institutes of Health (U.S.) (Grant R37-CA084198)National Institutes of Health (U.S.) (Grant RO1-CA087869

Episodic Memory and Appetite Regulation in Humans

Psychological and neurobiological evidence implicates hippocampal-dependent memory processes in the control of hunger and food intake. In humans, these have been revealed in the hyperphagia that is associated with amnesia. However, it remains unclear whether 'memory for recent eating' plays a significant role in neurologically intact humans. In this study we isolated the extent to which memory for a recently consumed meal influences hunger and fullness over a three-hour period. Before lunch, half of our volunteers were shown 300 ml of soup and half were shown 500 ml. Orthogonal to this, half consumed 300 ml and half consumed 500 ml. This process yielded four separate groups (25 volunteers in each). Independent manipulation of the 'actual' and 'perceived' soup portion was achieved using a computer-controlled peristaltic pump. This was designed to either refill or draw soup from a soup bowl in a covert manner. Immediately after lunch, self-reported hunger was influenced by the actual and not the perceived amount of soup consumed. However, two and three hours after meal termination this pattern was reversed - hunger was predicted by the perceived amount and not the actual amount. Participants who thought they had consumed the larger 500-ml portion reported significantly less hunger. This was also associated with an increase in the 'expected satiation' of the soup 24-hours later. For the first time, this manipulation exposes the independent and important contribution of memory processes to satiety. Opportunities exist to capitalise on this finding to reduce energy intake in humans

Mammal responses to global changes in human activity vary by trophic group and landscape

Wildlife must adapt to human presence to survive in the Anthropocene, so it is critical to understand species responses to humans in different contexts. We used camera trapping as a lens to view mammal responses to changes in human activity during the COVID-19 pandemic. Across 163 species sampled in 102 projects around the world, changes in the amount and timing of animal activity varied widely. Under higher human activity, mammals were less active in undeveloped areas but unexpectedly more active in developed areas while exhibiting greater nocturnality. Carnivores were most sensitive, showing the strongest decreases in activity and greatest increases in nocturnality. Wildlife managers must consider how habituation and uneven sensitivity across species may cause fundamental differences in human–wildlife interactions along gradients of human influence.Peer reviewe

Time-resolved, single-ended laser absorption thermometry and H 2 O, CO 2 , and CO speciation in a H 2 /C 2 H 4 -fueled rotating detonation engine

The article of record as published may be found at http://dx.doi.org/10.1016/j.proci.2020.06.125Proceedings of the Combustion Institute 38Rotating detonation engines (RDEs) require novel diagnostic tools to better understand complex detonation behavior and improve performance. To this end, a single-ended laser absorption sensor for in situ , time-resolved measurements of temperature, H 2 O, CO 2 , and CO concentrations has been developed and deployed within the annulus of a hydrogen/ethylene/air-fed RDE. With a measurement rate of 44 kS/s, the sensor delivers four co-aligned, mid-infrared laser beams into the annular detonation chamber and captures the back-reflected radiation through a single optical port. A ray-tracing optimization algorithm, designed to maximize signal-to-noise ratio and beam-perturbation tolerance, was used to determine the optimal sensor optical configuration. Wavelength-modulation spectroscopy (WMS) further compensated for interference sources in the harsh detonation environment. Time-resolved and time-averaged sensor measurements of gas temperature and species at equivalence ratios of 0.74, 0.87, and 1.03 are presented.Office of Naval ResearchInnovative Scientific Solution, Inc.Department of Defense through the National Defense Science and Engineering Graduate (NDSEG)N00014-15-P-112

Single-ended mid-infrared laser-absorption sensor for time-resolved measurements of water concentration and temperature within the annulus of a rotating detonation engine

The article of record as published may be found at http://dx.doi.org/10.1016/j.proci.2018.05.021A novel single-ended mid-infrared laser-absorption sensor for time-resolved measurements of water mole fraction and temperature was developed and deployed within the annulus of a hydrogen/air-fed rotating detonation engine (RDE). The sensor transmitted two laser beams targeting mid-infrared water transitions through a single optical port on the outer wall of the cylindrical RDE annulus and measured the backscattered radiation from the RDE inner surface using a photodetector for a round-trip path of 1.52 cm. Optimizing the sensor's optical arrangement using numerical ray tracing to minimize interference from optical emission, beam steering, and scattered laser light from window surfaces was essential to sensor performance. Scanned-wavelength-modulation spectroscopy with second-harmonic detection and first-harmonic normalization was implemented to allow for frequency-domain multiplexing of the two lasers and to suppress non-absorbing interference sources such as beam-steering and emission. Tunable diode lasers near 2551 and 2482 nm were modulated at 100 and 122 kHz, respectively, and sinusoidally scanned across the peaks of their respective water transitions at 10 kHz to provide a measurement rate of 20 kHz and detection limit of 0.5% water by mole. Experimentally derived spectroscopic parameters enabled water and temperature sensing with respective uncertainties of 7.3% and 5.3% relative to the measured values. Time-resolved and time-averaged sensor measurements of gas temperature and water vapor mole fraction allow quantitative evaluation of the combustion progress at the measurement location and thus provide a design tool for RDE optimization. Broadly, this single-ended laser sensor should find applications in other combustion systems where optical access is limited.Office of Naval ResearchInnovative Scientific Solutions Incorporated (ISSI)National Defense Science and Engineering Graduate (NDSEG) FellowshipGrant No. N00014-15-P-1121DoD, Air Force Office of Scientific Research and Army Research Offic

Dissolution and processing of cellulosic materials with ionic liquids: fundamentals and applications

With the inevitable depletion of petroleum-based resources, there has been an increasing worldwide interest in renewable resources such as biomass. One reason for the current approaches being taken to utilize biomass is the difficulty in processing lignocellulosic materials and the energy needed for separation of the components. The three major components of biomass are covalently bonded together, which makes dissolution and further separation of the three major components difficult and this has been recognized as the grand challenge for biomass utilization. This dissertation describes research efforts in processing of lignocellulosic biomass using ionic liquids (ILs) as solvents. ILs are salts with melting points below 100 oC, which possess many advantage properties. Cellulose composite fibers have been prepared based on IL solution with dispersion of the additives. Wood and bagasse have been completely dissolved in ILs. Partial separation of the components has been obtained using selected reconstitution solvents. High temperature and fast dissolution was found to be an efficient method for both dissolution and separation of biomass components. Biomass composite fibers can be prepared directly from such biomass solutions. With selected catalysts in solution, improved dissolution and separation has been achieved, making the delignification and pulp yield comparable to the kraft pulping process. (Published By University of Alabama Libraries

On the synthesis of copper-nickel binary alloy nanoparticles and binding silane coupling agents to magnetic ferrite nanoparticles

This dissertation addresses the creation of a multifunctional nanoplatform for cancer targeting, imaging, and therapy. Magnetic oxide nanoparticles were labeled with silane coupling agents that could be used for targeting. The magnetic oxides have application as contrast enhancing agents for magnetic resonance imaging. Copper-nickel binary alloy nanoparticles were prepared for possible use in Curie temperature limited hyperthermia therapy. Spherical, single crystal iron oxide nanoparticles with average diameters of 4 nm, 6 nm, 8 nm, 11 nm, or 16 nm were prepared using published procedures. The iron oxide particle chemistry was extended to synthesize 13 nm diameter CoFe_2 O_4 , 9 nm diameter MnFe_2 O_ 4 , and 12 nm diameter NiFe_2 O_4 . The particles had a coating of oleic acid and oleylamine ligands. Silane coupling chemistry was used to displace these ligands with either β-aminoethyl-ϒ-aminopropyl-trimethoxysilane, triethoxysilane-PEG, or triethoxysilane-biotin. The silane ligands would allow the particles to be conjugated with a targeting group. New chemistry was developed to synthesize fcc CuNi nanoparticles with the objective of finding methods that give particles with an average size less than 50 nm, a narrow distribution of particle sizes, and control of particle composition. The particle synthesis involves the reduction of a mixture of copper(II) and nickel(II) and the reduction conditions included diol reduction, polyol synthesis, seeding by diol reduction, and oleate reduction. One of the main issues is the formation of hcp nickel particles as a containment in the method. The factors that avoided the formation of hcp nickel particles and allow only fcc particles to form were the choice of reducing agent, ratio of surfactants, and heating time. Both the oleate reduction and diol reduction gave a mixture of the hcp and fcc phases. By controlling certain reaction conditions, such as keeping the ratio of oleic acid to oleylamine 1:1 and slowly heating to reflux for 30 minutes, only fcc nanoparticles were formed. The method of making CuNi nanoparticles by diol reduction gave the best result and it consisted of a total amount of 1 mmol of Cu(acac)_2 and Ni(acac)_2 , 5 mmol of 1,2 hexadecanediol, 1.5 mL of oleic acid, 1.5 mL of oleylamine and 15 mL of benzyl ether. It made fcc CuNi, provided control of composition, and gave particles with average size smaller than 100 nm. (Published By University of Alabama Libraries