Integration of Pasturing Systems for Cattle Finishing Programs

A 3-year study, using 84 fall-born and 28 spring-born calves of similar genotypes, was conducted to integrate pasturing systems with drylot feeding systems. Calves were started on test following weaning in May and October. Seven treatments were imposed: 1) fall-born calves directly into feedlot; 2 and 3) fall-born calves put on pasture with or without ionophore and moved to the feedlot at the end of July; 4 and 5) fall-born calves put on pasture with or without ionophore and moved to the feedlot at the end of October; 6 and 7) spring-born calves put on pasture with or without ionophore and moved to the feedlot at the end of October. A bromegrass pasture consisting of 16 paddocks, each 1.7 acre in size, was available. Each treatment group had access to 1 paddock at a time and was rotated at approximately 3-day intervals. In the feedlot, steers were provided an 82% concentrate diet containing whole-shelled corn, ground alfalfa hay, and a protein, vitamin and mineral supplement containing ionophore and molasses. As pens of cattle reached about 1150 lb. average live weight, they were processed and carcass traits were evaluated. Pasture daily gains were highest for cattle on pasture for the longest duration (P \u3c .03), and overall daily gains were highest for drylot cattle (P \u3c .01) and decreased with increased time spent on pasture. Although differences among treatments existed in numerical scores for yield and quality grades (P \u3c .05 and P \u3c .03, respectively), all treatments provided average yield grade scores of 2 and quality grades of low Choice or higher. Use of four production costs and pricing scenarios revealed that fall-born calves placed on pasture for varying lengths of time were the most profitable (P \u3c .04) among the treatments. Furthermore, employing a 5% price sensitivity analysis, indicated that fed-cattle selling price had great impact on profit potential and was followed in importance by feeder purchase price and corn grain price. Overall, these findings should provide significant production alternatives for some segments of the cattle feeding industry and also lend substantial credence to the concept of sustainable agriculture

Integration of Cool- and Warm-Season Grass Pasturing Systems into Cattle Finishing Programs

In a previous report (ISRF01-10), we reported on a study that demonstrated that fall-born steer calves pastured on bromegrass for either portions of or all of the grazing season and then finished in drylot, outperformed calves placed directly into the feedlot in terms of profit/head at harvest. Areas consisting of highly productive soils, interdispersed with highly erodible land, are well suited for this kind of production practice. Production systems of this nature are quite consistent with the concepts of sustainable agriculture. In an effort to capture more grazing potential, it was decided to incorporate warmseason grasses into the pasture program so that forage production would be enhanced during the hot summer months of July and August when cool-season grasses may become nearly dormant. Therefore, the objective of this multiyear study was to compare steer calves provided a combination of cool- and warm-season grass pastures with calves provided cool-season grass pastures only and followed by all calves being finished in drylot. Growth performance and carcass composition, were compared among treatments

The Effect on Meat Quality of Integrating Pasturing Systems into Cattle Finishing Programs

Forage source and quality in finishing cattle programs continue to be a source of concern because of economics and also because of their impact on beef eating qualities. The integration of pasturing systems for cattle finishing programs should allow the producer to produce a leaner and possibly more economical beef supply thus benefiting the consumer and the producer. This experiment was designed to investigate alternative pasture management systems for finishing cattle and to study the impact on meat quality

Market-Based Alternatives for Managing Congestion at New York’s LaGuardia Airport

We summarize the results of a project that was motivated by the expiration of the “High Density Rule,” which defined the slot controls employed at New York’s LaGuardia Airport for more than 30 years. The scope of the project included the analysis of several administrative measures, congestion pricing options and slot auctions. The research output includes a congestion pricing procedure and also the specification of a slot auction mechanism. The research results are based in part on two strategic simulations. These were multi-day events that included the participation of airport operators, most notably the Port Authority of New York and New Jersey, FAA and DOT executives, airline representatives and other members of the air transportation community. The first simulation placed participants in a stressful, high congestion future scenario and then allowed participants to react and problem solve under various administrative measures and congestion pricing options. The second simulation was a mock slot auction in which participants bid on LGA arrival and departure slots for fictitious airlines.Auctions, airport slot auctions, combinatorial auctions

Composition and Structure of the Inorganic Core of Relaxed Intermediate

Activation of the diferrous center of the β2 (R2) subunit of the class 1a Escherichia coli ribonucleotide reductases by reaction with O2 followed by one-electron reduction yields a spin-coupled, paramagnetic Fe(III)/Fe(IV) intermediate, denoted X, whose identity has been sought by multiple investigators for over a quarter of a century. To determine the composition and structure of X, the present study has applied 57Fe, 14,15N, 17O, and 1H electron nuclear double resonance (ENDOR) measurements combined with quantitative measurements of 17O and 1H electron paramagnetic resonance line-broadening studies to wild-type X, which is very short-lived, and to X prepared with the Y122F mutant, which has a lifetime of many seconds. Previous studies have established that over several seconds the as-formed X(Y122F) relaxes to an equilibrium structure. The present study focuses on the relaxed structure. It establishes that the inorganic core of relaxed X has the composition [(OH–)FeIII–O–FeIV]: there is no second inorganic oxygenic bridge, neither oxo nor hydroxo. Geometric analysis of the 14N ENDOR data, together with recent extended X-ray absorption fine structure measurements of the Fe–Fe distance (Dassama, L. M.; et al. J. Am. Chem. Soc. 2013, 135, 16758), supports the view that X contains a “diamond-core” Fe(III)/Fe(IV) center, with the irons bridged by two ligands. One bridging ligand is the oxo bridge (OBr) derived from O2 gas. Given the absence of a second inorganic oxygenic bridge, the second bridging ligand must be protein derived, and is most plausibly assigned as a carboxyl oxygen from E238.United States. National Institutes of Health (GM 111097)United States. National Institutes of Health (GM 29595

Dynamic Solidification in Nanoconfined Water Films

Mechanical properties of nanoconfined water layers are still poorly understood and continue to create controversy, despite their importance for biology and nanotechnology. We report on dynamic nanomechanical measurements of water films compressed to a few single molecular layers. We show that the mechanical properties of nanoconfined water layers change significantly with their dynamic state. In particular, we observed a sharp transition from viscous to elastic response even at extremely slow compression rates, indicating that mechanical relaxation times increase dramatically once water is compressed to less than 3–4 molecular layers

Progress Report: Pasture Finishing of Beef Steers Using Contemporary Feedlot Protocols

Environmental regulations in Iowa can place animal population restrictions on a given site. This study explores the possibility of finishing cattle in a remote pasture location to handle an overflow of animals and yet remain in compliance with environmental mandates

Progress Report: Effects of Condensed Corn Distillers Solubles on Steer Performance and Carcass Composition

Condensed, corn, distillers solubles provides an effective energy supplement for finishing cattle across a number of finishing systems

Robust, reproducible, industrialized, standard membrane feeding assay for assessing the transmission blocking activity of vaccines and drugs against Plasmodium falciparum.

BackgroundA vaccine that interrupts malaria transmission (VIMT) would be a valuable tool for malaria control and elimination. One VIMT approach is to identify sexual erythrocytic and mosquito stage antigens of the malaria parasite that induce immune responses targeted at disrupting parasite development in the mosquito. The standard Plasmodium falciparum membrane-feeding assay (SMFA) is used to assess transmission-blocking activity (TBA) of antibodies against candidate immunogens and of drugs targeting the mosquito stages. To develop its P. falciparum sporozoite (SPZ) products, Sanaria has industrialized the production of P. falciparum-infected Anopheles stephensi mosquitoes, incorporating quantitative analyses of oocyst and P. falciparum SPZ infections as part of the manufacturing process.MethodsThese capabilities were exploited to develop a robust, reliable, consistent SMFA that was used to assess 188 serum samples from animals immunized with the candidate vaccine immunogen, Pfs25, targeting P. falciparum mosquito stages. Seventy-four independent SMFAs were performed. Infection intensity (number of oocysts/mosquito) and infection prevalence (percentage of mosquitoes infected with oocysts) were compared between mosquitoes fed cultured gametocytes plus normal human O(+) serum (negative control), anti-Pfs25 polyclonal antisera (MRA39 or MRA38, at a final dilution in the blood meal of 1:54 as positive control), and test sera from animals immunized with Pfs25 (at a final dilution in the blood meal of 1:9).ResultsSMFA negative controls consistently yielded high infection intensity (mean = 46.1 oocysts/midgut, range of positives 3.7-135.6) and infection prevalence (mean = 94.2%, range 71.4-100.0) and in positive controls, infection intensity was reduced by 81.6% (anti-Pfs25 MRA39) and 97.0% (anti-Pfs25 MRA38), and infection prevalence was reduced by 12.9 and 63.5%, respectively. A range of TBAs was detected among the 188 test samples assayed in duplicate. Consistent administration of infectious gametocytes to mosquitoes within and between assays was achieved, and the TBA of anti-Pfs25 control antibodies was highly reproducible.ConclusionsThese results demonstrate a robust capacity to perform the SMFA in a medium-to-high throughput format, suitable for assessing large numbers of experimental samples of candidate antibodies or drugs

Estimation and analysis of beef gain roughage-concentrate production functions

Through the 1960s and early 1970s, many cattle feeders formulated feedlot rations composed primarily of grains. Rations high in grain were relatively inexpensive and economical. For example, Scott and Broadbent [20] constructed a programming model in 1972 that utilized the California net energy system as developed by Lofgreen and Garett [16] and adopted by the National Research Council (NRC) of the National Academy of Sciences (NAS) to estimate economical rations. They concluded, In most feedlot operations, it appears that the maximum possible rate of gain w ill be most profitable under usual price relationships” [20, p. 24]. Although maximizing rate of gain is a biological objective, it was congruent with the economic objective of maximizing profits. Therefore, there were several reasons for little interest in investigating the trade-off or substitution rates between roughages and concentrates in the beef feeding ration. First, concentrates were relatively inexpensive. Second, addition of roughages to rations generally reduces rate of gain. A longer time on feed thus increases the nonfeed costs, such as labor, yardage fees, and carrying charges, and reduces the annual volume of a lot. Third, roughages generally are bulkier and more difficult to handle than concentrates. They may require more expensive equipment and large long-term capital investments. Fourth, many feedlots were designed and constructed to provide high-concentrate rations. Hence, little effort was exerted toward investigating the rate of substitution between roughages and concentrates