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Breeding to improve biomass production of switchgrass (Panicum virgatumL.) and big bluestem (Andropogon gerardiiVitman) for conversion to bioenergy began in 1992. The purpose of this study was (i) to develop a platform for uniform regional testing of cultivars and experimental populations for these species, and (ii) to estimate the gains made by breeding during 1992 to 2012. A total of 25 switchgrass populations and 16 big bluestem populations were planted in uniform regional trials at 13 locations in 2012 and 2014. The reference region was USDA Hardiness Zones 3 through 6 in the humid temperate United States. Significant progress toward increased biomass yield was made in big bluestem and within upland‐ecotype populations, lowland‐ecotype populations, and hybrid‐derived populations of switchgrass. Four mechanisms of increasing biomass yield were documented: (i) increased biomass yield per se, (ii) later flowering to extend the growing season, (iii) combined later flowering from the lowland ecotype with survivorship of the upland ecotype in hybrid‐derived populations, and (iv) increased survivorship of late‐flowering lowland populations in hardiness zones that represent an expansion of their natural adaption zone. Switchgrass exhibited all four mechanisms in one or more improved populations, whereas improved populations of big bluestem were likely influenced by two of the four mechanisms. The uniform testing program was successful at documenting increases in biomass yield, identifying the mechanisms for increased yield, and determining adaptation characteristics and limitations of improved populations.

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This article presents an integrated analytical model on the injection efficiencies of the different ion species of the Anomalous component of the Cosmic Rays (ACRs) at the solar wind termination shock. We find that the injection into diffusive (first-order Fermi) acceleration is dominated by parallel ion diffusion and not by perpendicular diffusion unless the angle Ψbetween the shock normal and the heliospheric magnetic field is almost exactly 90° ($89.3^\circ < \Psi \approx 90^\circ$). In steady state the threshold speed for injection into first-order Fermi acceleration at a not exactly perpendicular solar wind termination shock – with the Parker shock angle $\Psi \approx 89.3^\circ$– adjusts itself self-consistently. Increased anisotropic ACR flux amplifies Alfvénic turbulence which in turn suppresses parallel diffusion. It therefore increases the injection threshold and decreases the ACR flux until equilibrium is reached. For this equilibrium situation, we estimate the injection efficiencies of different species of suprathermal ions at the termination shock. We consider the following pre-acceleration processes: 1) momentum diffusion in compressional (ion-acoustic and magnetosonic) turbulence in the upstream supersonic solar wind and adiabatic cooling during convection to the termination shock; 2) reflection, transmission, and acceleration in the electric potential of the termination shock; and 3) momentum diffusion (stochastic or second-order Fermi acceleration) in the subsonic solar wind downstream of the termination shock in the inner heliosheath region. Our model results are compared to data from instruments on board the SOHO, ACE, Ulysses, and Voyager spacecraft.

A coordinated effort to combine all three methods that are used to determine the physical parameters of interstellar gas in the heliosphere has been undertaken. In order to arrive at a consistent parameter set that agrees with the observations of neutral gas, pickup ions and UV backscattering we have combined data sets from coordinated observation campaigns over three years from 1998 through 2000. The key observations include pickup ions with ACE and Ulysses SWICS, neutral atoms with Ulysses GAS, as well as UV backscattering at the He focusing cone close to the Sun with SOHO UVCS and at 1 AU with EUVE. For the first time also the solar EUV irradiance that is responsible for photo ionization was monitored with SOHO CELIAS SEM, and the He I 58.4 nm line that illuminates He was observed simultaneously with SOHO SUMER. The solar wind conditions were monitored with SOHO, ACE, and WIND. Based on these data the modeling of the interstellar gas and its secondary products in the heliosphere has resulted in a consistent set of interstellar He parameters with much reduced uncertainties, which satisfy all observations, even extended to earlier data sets. It was also established that a substantial ionization in addition to photo ionization, most likely electron impact, is required, with increasing relative importance closer to the Sun. Furthermore, the total combined ionization rate varies significantly with solar latitude, requiring a fully three dimensional and time dependent treatment of the problem.

The two-dimensional model of the solar wind-local interstellar medium interaction developed by Baranov & Malama ([CITE], J. Geophys. Res., 98, 15 157) is improved by taking into account the dynamical effect of anomalous cosmic rays. The cosmic rays are treated as a massless diffusive fluid. It is shown that the termination shock shifts further away from the Sun in this case and the post-shock temperature of the thermal plasma decreases. The magnitude of the shift depends on the value of the energy-averaged spatial diffusion coefficient. The number density of energetic neutral hydrogen originating in the shocked solar wind is generally lower in the case of the cosmic-ray-modified termination shock.

Beef cattle consume more tall fescue [Lolium arundinaceum(Schreb.) Darbysh.] than any other perennial cool-season grass in North America. Tall fescue forms a mutualistic relationship with the fungus Epichloë coenophiala(Morgan-Jones and W. Cams) C.W. Bacon & Schardl, comb. nov.; these plants are often referred to as endophyte-infected tall fescue. Agronomically, endophyte infection is good; endophyte-infected plants resist biotic and abiotic stresses better than do endophyte-free plants. However, tall fescue plants infected with a common toxic endophyte produce the ergot alkaloids that cause tall fescue toxicosis. Several agronomic practices can eliminate or reduce the effects of tall fescue toxicosis. Renovating tall fescue fields infected with a common toxic endophyte to new cultivars infected with a novel (or nontoxic) endophyte eliminates the problem for that field. Although the cost to renovate currently exceeds US$600/ha, most economic analyses show it to be a good long-term investment, especially on fields with high forage production potential. Less effective, but popular, methods of dealing with tall fescue toxicosis include adding clovers (Trifoliumspp.) or other forage species to the pastures to dilute the effects of the toxins, avoiding the use of high rates of nitrogen fertilizers, feeding supplements, and rotating cattle to warm-season forages in summer. Also, the alkaloid concentration in forage can be reduced by making it (drying) into hay. Recent research shows that animal tolerance to tall fescue toxicosis is possible, although there is still much to learn about this topic. Tall fescue toxicosis is likely a reality in the beef industry for some time to come. We contend that renovation of the most productive fields to cultivars infected with a novel endophyte coupled with the prospect of using tolerant livestock in scenarios where renovation is not possible will give innovative producers a competitive edge.

The primary objective was to determine the feasibility of harvesting switchgrass (Panicum virgatumL.) for biomass and/or forage in a single season. Plots were located at Mt. Vernon, on Viraton silt loam (fine‐loamy, siliceous, active, mesic Oxyaquic Fragiudalf), and Columbia, on Mexico silt loam (fine, smectitic, mesic Vertic Epiaqualf), both in Missouri. Forage/biomass yields and nutritive value of samples intended for forage use, were compared between four harvest management treatments: a single post‐frost harvest for biomass (Treatment I), a forage harvest at boot stage followed by a post‐frost biomass harvest (Treatment II), biomass harvest at postanthesis with late summer regrowth harvested as forage (Treatment III) and biomass harvest at preanthesis with late summer regrowth harvested as forage (Treatment IV). A complementary study was conducted to determine the effects of switchgrass maturity stage on efficiency of conversion to glucose through enzymatic hydrolysis. Both studies were conducted in 2010 and 2011. The single, post‐frost harvest (Treatment I) yielded as much as or more biomass than any other treatment. At Mt. Vernon in both years, yields intended for forage use were greatest for Treatment II. At Columbia, forage yields were greatest for Treatment IV in 2010 while there was no difference between treatments in 2011. When forage harvests were compared, summer regrowth was generally more lignified than growth harvested at boot stage. Two‐harvest systems can yield as much as single harvest systems; producers should weigh the economic value of forage vs. biomass before deciding which strategy fits best.

Pasture‐based dairy operators usually aim to optimize defoliation intensity to maximize forage production and nutritive value. The objective was to determine forage accumulation, nutritive value, and tiller density of tall fescue [Lolium arundinaceum(Schreb.) Darbysh.] and perennial ryegrass (L. perenneL.) when repeatedly mowed to a stubble height of 2.5, 5, 7.5, 10, 12.5, or 15 cm. In a 2‐yr study conducted near Columbia, MO, plots were mown to their respective stubble height whenever they grew to a “trigger” height of 20 to 22 plate meter units (approximately 4000 kg ha−1dry matter [DM] to soil surface). In Year 1, tall fescue mowed to 2.5 cm accumulated 14,440 kg ha−1which was the most of any treatment. In Year 2, forage accumulation for tall fescue mowed to 2.5, 5, or 7.5 cm did not differ, but was approximately 15% more than perennial ryegrass mowed to the same heights. For both species, forage harvested at stubble heights ≥10 cm had greater nutritive value than at heights of ≤7.5 cm. Perennial ryegrass had 60% fewer tillers for stubble heights ≤7.5 cm compared to heights ≥10 cm. Tall fescue showed no difference in tiller density for any stubble height. Milk production ha−1, predicted via MILK2006, was greater for stubble heights ≤7.5 cm, primarily due to greater forage accumulation. This study showed that tall fescue is better suited than perennial ryegrass for pasture‐based dairies in the Midwest because of its greater forage yield, estimated milk production, and stand (tiller) density.

Continental tall fescue [Festuca arundinaceaSchreb. syn. Lolium arundinaceum(Schreb.) Darbysh.] is the predominant forage used by cattle producers throughout much of the Midwest. However, Mediterranean tall fescue is gaining popularity in warmer, drier climates. One major difference of Mediterranean tall fescue is that it enters a semidormant period during hot dry summers but resurges during the fall and winter months. During the autumn resurgence it has exceptional growth but does not survive prolonged freezing conditions typically found in the Midwest. To determine how both Continental and Mediterranean tall fescues respond to low temperatures that are typically encountered during the fall, the leaf extension rate (LER) was measured along with proline, simple sugars, fructan, and abscisic acid (ABA). Three Mediterranean and four Continental accessions were tested, including Kentucky‐31 and Flecha as “typical” Continental and Mediterranean accessions, respectively. The greatest difference observed between these types of tall fescue occurred at 4.5°C. The Mediterranean genotypes had greater LER and fructan concentrations while the Continental genotypes possessed greater proline, ABA, and simple sugar concentrations. Kentucky‐31 was typically found in the middle between the Mediterranean and the remaining Continental accessions. These data indicate that Mediterranean germplasm possesses superior cold growth, but the high proline levels produced by the Continental types may be critical for survival under cold conditions.

Tall fescue [Festuca arundinaceaSchreb. syn. Lolium arundinaceum(Schreb.) Darbysh.] is widely used for hay and pasture in the Eastern regions of the United States, with new types of Mediterranean tall fescue possessing superior growth under cool growing conditions. However, they do not survive Midwestern winters. To date, little research has examined the role of endophyte infection on the ability of tall fescue to grow under cold conditions or survive freezing conditions. This study's objectives determined the endophyte's role in tall fescue growth and production of metabolites for nonfreezing conditions. Additionally, the role of endophyte infection on the ability of plants to survive freezing temperatures was determined. This experiment used five genotypes of tall fescue. Half of the plants from each genotype were endophyte infected (E+), with the remaining genotypes being endophyte free (E–). We report for the first time the effects of endophyte status on proline, simple sugars, and fructan accumulation when plants were grown under cold, nonfreezing temperatures and the survivability at various freezing temperatures. Endophyte removal only affected fructan concentrations at 4.5°C; however, plant genotype affected leaf extension rate, proline, sugars, and fructan concentration. The freezing test found no effect of the endophyte on tiller survival, while plant genotype was significant. These data indicate that endophyte removal has little influence on the measured traits, and plant genotype is more critical for survival under cold conditions.

The daily BW gain of stocker steers grazing tall fescue [Lolium arundinaceum(Schreb.) S.J. Darbysh. = Schedonorus arundinaceus(Schreb.) Dumort.]-based pastures typically declines during summer. To avoid these declines, in part to mitigate the effects of tall fescue toxicosis, it is commonly advised to move cattle to warm-season forage during this period. A 3-yr (2006, 2007, and 2008) grazing study was conducted to evaluate the effect of replacing 25% of the area of a tall fescue/clover (81% endophyte-infected) pasture system with “Ozark” bermudagrass [Cynodon dactylon(L.) Pers.] overseeded with clover (Trifoliumspp.) to provide summer grazing for stocker steers (TF+BERM). The TF+BERM treatment was compared with a grazing system in which tall fescue/clover (TF) pastures were the only type of forage available for grazing. Our objective was to determine if replacement of 25% of the land area in a fescue system with bermudagrass would increase annual beef production compared with a system based solely on tall fescue. The study was conducted at the Southwest Research and Education Center of the University of Missouri near Mt. Vernon. Each treatment was rotationally stocked with 5 steers (248 ± 19.3 kg) on 1.7 ha. Fertilizer applications were applied at rates recommended for each respective forage species. Total forage production, BW gain per hectare, and season-long ADG of steers was greater (P< 0.06) for TF+BERM than for TF in 2006, but none of these measures differed (P> 0.19) in 2007 or 2008. In vitro true digestibility of pastures was greater (P= 0.01) for TF (84.4%, SEM = 0.64%) compared with TF+BERM (80.6%, SEM = 0.79%), even in summer. The decreased in vitro true digestibility of the bermudagrass pastures likely negated any benefit that animals in TF+BERM had in avoiding the ergot-like alkaloids associated with endophyte-infected tall fescue. Renovating 25% of the pasture system to bermudagrass provided some benefit to the system in years when summertime precipitation was limited (2006) but provided no value in wetter years (2007 and 2008). Although renovating endophyte-infected tall fescue pastures to a warm-season forage is a widely used practice to mitigate tall fescue toxicosis, the benefits of this practice are limited if forage quality of the warm season component is poor.

A 2-yr production study was conducted to evaluate 3 systems of growing stocker calves under rotational stocking. One group of steers was stocked on pasture from early April to mid August (spring-stocked steers = SSS), and another group of steers was stocked from early July to late October (fall-stocked steers = FSS). Steers were stratified by BW (n = 72, BW = 229 ± 11 kg for SSS; n = 72, BW = 248 ± 18 kg for FSS) and randomly assigned to 1 of 3 treatments. The 3 treatments were 1) rotationally stocked only (control; CON), steers rotated to a new paddock as forage availability dropped below acceptable levels in the occupied paddock; 2) rotationally stocked with distillers grains (DIST); this was the same as CON except steers were supplemented with varying amounts of distillers dried grains with solubles (DDGS) based on forage nutritive value; and 3) rotationally stocked with round-bale silage (SIL); excess forage in spring was harvested and stored as round-bale silage and fed back as needed. Total BW gain/ha over the entire grazing season did not differ between DIST and SIL (P= 0.09) steers, but both were greater than CON (P< 0.01). Total BW gain/ha for DIST, SIL, and CON was 459 (SEM = 11.5), 402 (SEM = 31.0), and 276 (SEM = 26.2) kg, respectively. For ADG, there was a group × year (P< 0.01) and group × treatment (P= 0.02) interaction. Steer ADG for SSS did not differ between SIL and DIST (P= 0.51), but was greater than the CON (P= 0.01). The ADG for SSS was 0.79 (SEM = 0.04), 0.81 (SEM = 0.05), and 0.62 (SEM = 0.05) kg for DIST, SIL, and CON, respectively. For the FSS, ADG for all 3 treatments was different (P= 0.02). The FSS ADG was 0.72 (SEM = 0.03), 0.53 (SEM = 0.04), and 0.29 (SEM = 0.04) kg for DIST, SIL, and CON, respectively. The only treatment with equivalent (P= 0.07) ADG between early and late-stocked steers (SSS vs. FSS) was DIST. Adjusting the amount of DDGS supplemented to steers based on forage nutritive value resulted in consistent BW gains throughout the grazing study, whereas steers in the SIL and CON treatments gained less BW during the latter portion of the season. Controlling forage maturity by removal in the SIL treatment resulted in total BW gains/ha that were not different than the DIST treatment.

Recent research shows that the meat from beef animals finished on pasture has greater concentrations of omega‐3 fatty acid (FA) and conjugated linoleic acids (CLA) compared with animals finished on high‐concentrate diets. However, little is known about the FA concentrations in forage that might alter these FA in the meat of pasture‐finished beef. The objective was to determine the FA variation between and within forage species commonly grown in pastures in the Midwest. A secondary objective was to identify phenotypic characteristics that may be associated with individual FA. The forages analyzed included multiple cultivars of orchardgrass (Dactylis glomerataL.), tall fescue [Lolium arundinaceum(Schreb.) S.J. Darbyshire = Schedonorus phoenix(Scop.) Holub], perennial ryegrass (Lolium perenneL.), and alfalfa [Medicago sativaL. ssp. sativaand falcata(L.) Arcang.]. Grasses had higher amounts of α‐linolenic (C18:3) acid compared with alfalfa. Conversely, alfalfa had larger amounts of linoleic acid (C18:2) than did the grasses. Correlations between phenotypic traits and specific FA were found; plant total chlorophyll had the greatest correlation to total FA concentration. Overall, there is not a large amount of within‐species variation that breeders could use to make large changes in FA concentrations.

Common tall fescue [Lolium arundinaceum(Schreb.) Darbysh. = Schedonorus arundinaceus(Schreb.) Dumort.] is infected with a fungus that produces ergot alkaloids, a class of compounds associated with fescue toxicosis. The objective of this research was to monitor the change in concentrations of ergot alkaloids from time of clipping through storage of tall fescue hay. A 2‐yr field study was conducted in Mt. Vernon, MO, in which tall fescue was baled at high moisture (204–219 g H2O kg−1dry matter [DM]) and low moisture (102–112 g H2O kg−1DM) then stored for 18 mo. Hay samples were collected over the 540‐d period from clipping through storage and analyzed for ergovaline and total ergot alkaloid concentration. Data were analyzed using standard ANOVA procedures and break‐point regression. In both years, ergovaline concentrations decreased sharply within the first month after harvest and gradually over the remaining 17 mo. In three of the four cases, most of the ergovaline disappearance occurred within 3 d after clipping. The final ergovaline concentration remained above 250 μg kg−1DM, which is still considered toxic to livestock. In the first year, ergot alkaloid concentration followed a pattern similar to ergovaline concentration. In the second year, however, the decrease in total ergot alkaloid was gradual throughout the entire 18 mo. A general recommendation to producers would be to delay feeding toxic tall fescue hay until at least 1 mo after clipping.

Pasture‐based dairies in the Midwest have a difficult time providing high‐quality pasture during winter. Little is known about the yield and nutritive value of festulolium when stockpiled for winter grazing compared to tall fescue. In this study, the yield and nutritive value of ‘Jesup’ endophyte‐free tall fescue [Schedonorus phoenix(Scop.) Holub.] and ‘Spring Green’ festulolium [Festulolium loliaceum(Hudson) P.V. Fournier] were evaluated monthly from November to March over three years. The research was conducted near Mt. Vernon, MO, on a Gerald silt loam (fine, mixed, active, mesic Aeric Fragiaqualf). In two of the three years, stockpiled tall fescue out‐yielded festulolium by as much as 930 kg ha−1Both tall fescue and festulolium yields decreased over winter by approximately the same percentage; losses from November to March ranged from 32 to >75%. The nutritive value of stockpiled festulolium was consistently greater than stockpiled tall fescue during winter. Both stockpiled festulolium and tall fescue contain sufficient crude protein and total digestible nutrients at one times maintenance to maintain most small breed dairy cows during their dry period but would be severely lacking once lactation started. Despite the greater nutritive value of stockpiled Spring Green festulolium compared to Jesup tall fescue, the low forage yield of festulolium makes its use questionable for pasture‐based dairies.

Although feed intake and efficiency differences in growing cattle of low and high residual feed intake (RFI) classification have been established, little is known about the difference in grazed forage intake between beef cows of known RFI classification. Two experiments were conducted using Hereford cows for which RFI had been determined as heifers using the GrowSafe 4000E feed intake system, after which heifers had been divided into thirds as low RFI, mid RFI, and high RFI. During Exp. 1, 2 replicates of low and high RFI cows (n = 7/replicate) in mid- to late-gestation were blocked to 1 of 4 non-endophyte-infected tall fescue paddocks (1.8 to 2.4 ha), which they grazed continuously for 84 d during summer. Using grazing exclosures, weekly rising plate meter readings, and forage harvests every 21 d, average forage DMI was calculated. Low and high RFI groups did not differ (P> 0.05) in BW change or BCS change over the trial (19.5 vs. 22.1 kg of BW gain and 0.11 vs. 0.10 BCS gain), but low RFI cows had a 21% numerically lower DMI than high RFI cows (12.4 vs. 15.6 kg/d; P= 0.23). The average area needed per paddock over the trial was similar for low and high RFI cows (1.71 vs. 1.82 ha; P= 0.35), and the average DM on offer over the trial was less for low RFI than for high RFI cows (4,215 vs. 4,376 kg; P= 0.06). During Exp. 2, 3 replicates of low and high RFI cows with their calves (n = 4 pair/replicate) strip-grazed stockpiled and early spring growth tall fescue paddocks (0.7 to 0.9 ha) for 60 d in late winter and early spring. Because of limiting forage availability and quality at trial initiation, cow-calf pairs were also fed 3.31 kg/pair of pelleted soyhulls daily. Pre- and post-grazed forage samples were harvested for 4 grazing periods, and forage growth was estimated using a growing degree days calculation and on-site weather station data. Performance did not differ (P> 0.05) between low and high RFI cows throughout the experiment (18.4 vs. 26.6 kg of BW gain and −0.04 vs. 0.15 BCS gain). Despite the utilization of forage offered being similar for low and high RFI cow-calf pairs (P> 0.05), low RFI cows and their calves had an 11% numerically lower DMI than high RFI pairs (12.5 vs. 14.1 kg/d; P= 0.12). We concluded that either no intake differences existed between low and high RFI cows or that current methodology and small animal numbers limited our ability to detect differences.

In a 2-yr study, we evaluated the effect of different forage allocations on the performance of lactating beef cows and their calves grazing stockpiled tall fescue. Allocations of stockpiled tall fescue at 2.25, 3.00, 3.75, and 4.50% of cow-calf pair BW/d were set as experimental treatments. Conventional hay-feeding was also evaluated as a comparison to grazing stockpiled tall fescue. The experiment had a randomized complete block design with 3 replications and was divided into 3 phases each year. From early December to late February (phase 1) of each year, cows and calves grazed stockpiled tall fescue or were fed hay in the treatments described above. Immediately after phase 1, cows and calves were commingled and managed as a single group until weaning in April (phase 2) so that residual effects could be documented. Residual effects on cows were measured after the calves were weaned in April until mid-July (phase 3). During phase 1 of both years, apparent DMI of cow-calf pairs allocated stockpiled tall fescue at 4.50% of BW/d was 31% greater (P< 0.01) than those allocated 2.25% of BW/d. As allocation of stockpiled tall fescue increased from 2.25 to 4.50% of cow-calf BW/d, pasture utilization fell (P< 0.01) from 84 ± 7% to 59 ± 7%. During phase 1 of both years, cow BW losses increased linearly (P< 0.02) as forage allocations decreased, although the losses in yr 1 were almost double (P< 0.01) those in yr 2. During phases 2 and 3, few differences were noted across treatment groups, such that by the end of phase 3, cow BW in all treatments did not differ either year (P> 0.40). Calf ADG in phase 1 increased linearly (P< 0.01) with forage allocation (y = 0.063x + 0.513; R2= 0.91). However, calf gain per hectare decreased linearly (P< 0.01) as stockpiled tall fescue allocations increased (y = −26.5× + 212; R2= 0.97) such that gain per hectare for cow-calf pairs allocated stockpiled tall fescue at 4.50% BW/d was nearly 40% less (P< 0.01) than for those allocated 2.25% of BW/d. Allocating cow-calf pairs stockpiled tall fescue at 2.25% of BW/d likely optimizes its use; because cow body condition is easily regained in the subsequent spring and summer months, less forage is used during winter, and calf gain per hectare is maximized.

Switchgrass (Panicum virgatumL.) is a warm‐season native grass, used for livestock feed, bioenergy, soil and wildlife conservation, and prairie restoration in a large portion of the USA. The objective of this research was to quantify the relative importance of latitude and longitude for adaptation and agronomic performance of a diverse group of switchgrass populations. Six populations, chosen to represent remnant prairie populations on two north–south transects, were evaluated for agronomic traits at 12 locations ranging from 36 to 47°N latitude and 88 to 101°W longitude. Although the population × location interactions accounted for only 10 to 31% of the variance among population means, many significant changes in ranking and adaptive responses were observed. Ground cover was greater for northern‐origin populations evaluated in hardiness zones 3 and 4 and for southern‐origin populations evaluated in hardiness zones 5 and 6. There were no adaptive responses related to longitude (ecoregion). Switchgrass populations for use in biomass production, conservation, or restoration should not be moved more than one hardiness zone north or south from their origin, but some can be moved east or west of their original ecoregion, if results from field tests support broad longitudinal adaptation.

We examined the effect of endophyte infection level of tall fescue (Festuca arundinaceaSchreb.) used for stockpiled forage on the performance of lactating, fallscalving beef cows and their calves. Treatments were endophyte infection levels of 20% (low; SEM = 3.5), 51%, (medium; SEM = 1.25), and 89% (high; SEM = 2.4; 4 replications/treatment). Five cow-calf pairs grazed in each replicate (n = 60 cow-calf pairs/ yr) for 84 d (phase 1) starting on December 2, 2004 (yr 1), and December 1, 2005 (yr 2). After 84 d of grazing each treatment, the cattle were commingled and fed as a single group (phase 2) until weaning in April of each year. Phase 2 allowed measurement of residual effects from grazing stockpiled tall fescue with varying levels of endophyte infection. Pregrazing and postgrazing forage DM yield, forage nutritive value, and total ergot alkaloid concentrations of forage were collected every 21 d during phase 1. Animal performance data included cow BW, ADG, and BCS, as well as calf BW and ADG. Animal performance was monitored during both phases. Endophyte infection did not affect (P= 0.52) apparent intake (pregrazing minus postgrazing forage DM yield) of stockpiled tall fescue, because each cow-calf pair consumed 16 ± 1.7 kg/d regardless of treatment. Cow ADG during phase 1 was −0.47 ±0.43 kg for the low treatment, which was greater (P< 0.01) than either the medium (−0.64 ±0.43 kg) or high (−0.74 ± 0.43 kg) treatments. However, cows that had grazed the high or medium treatments in phase 1 lost −0.43 and −0.57 (±0.24) kg/d, respectively, which was less (P<0.01) BW loss than the cows in the low (−0.78 ± 0.24 kg/d) treatment during phase 2. By the end of phase 2, cow BW did not differ (528 ±27 kg; P= 0.15). Body condition score for cows in the low treatment was greater (P= 0.02) than that of the medium and high treatments at the end of phase 1. Body condition scores did not change appreciably by the end of phase 2, and differences among treatments remained the same as at the end of phase 1 (P= 0.02). In contrast to cow performance, calf ADG was unaffected (P= 0.10) by endophyte level and averaged 0.73 ± 0.07 kg during phase 1 and 0.44 ± 0.04 kg during phase 2. Our data suggest that fall-calving herds can utilize highly-infected tall fescue when stockpiled for winter grazing, with little impact on cow performance and no impact on calf gain.

Ergot alkaloids are a class of toxic compounds, some of which are produced by a fungal endophyte in tall fescue (Festuca arundinaceaSchreb.). The objective of this research was to measure total ergot alkaloid content in tall fescue by near‐infrared (NIR) spectroscopy with a calibration developed from immunochemical reference data. Eighty‐four tall fescue samples were collected from experiments at the University of Missouri. Samples were from plants that varied in maturity, endophyte status, genotype, growing environment, and storage and preservation treatment. Samples were scanned by NIR radiation and analyzed chemically for ergot alkaloid content using a commercial immunoassay. An empirical prediction equation was developed by regressing NIR reflectance data against absorbance data from the immunoassay. The initial calibrations achieved a 1 − variance ratio (VR) of 0.86 with a mean and standard error of cross validation (SECV) of 0.606 ± 0.12; however, this was possible only when stockpiled tall fescue samples were omitted from the population. Stockpiled samples were checked for chemical accuracy and spectral similarity to the population, and another set of calibrations was developed. The final calibration, which omitted only those stockpiled samples that were infected with a toxic endophyte, had a 1 − VR of 0.89, with a mean and SECV of 0.682 ± 0.11. We concluded that total ergot alkaloid content in tall fescue can be quantified by NIR spectroscopy with a calibration developed from immunochemcial data, though it may not be possible to include samples of stockpiled tall fescue if they are infected with a toxic endophyte. Such a calibration can be robust and precise, reliably predicting an entire class of compounds in a diverse population of tall fescue samples.

Livestock operations, particularly pasture‐based dairies in the lower Midwest, are interested in stockpiling annual ryegrass (Lolium multiflorumLam.) as a source of high‐quality winter forage. Almost no information exists about stockpiling annual ryegrass in this region. Our objective was to determine the yield and forage quality of stockpiled annual ryegrass compared with cereal rye during winter in the lower Midwest. ‘Barmultra’ and ‘Marshall’ annual ryegrass were evaluated at two locations (Columbia and Mt. Vernon, MO) during the winters of 1998‐1999 (Year 1) and 1999‐2000 (Year 2). ‘Forage Master’ cereal rye (Secale cerealeL.) was included as a comparison. Uncut strips (subplots) were harvested monthly from mid‐December through mid‐March each year. Stockpiled annual ryegrass yields ranged from 825 to 2356 kg ha−1, with Marshall yielding more than Barmultra on all but one harvest date during the 2 yr. Forage quality of stockpiled annual ryegrass typically declined from mid‐December through mid‐February, with a larger decline in a normal winter (Year 1) than in a mild winter (Year 2). Although forage quality tended to decline during winter, acid detergent fiber (ADF) never exceeded 252 g kg−1, and neutral detergent fiber (NDF) never exceeded 455 g kg−1This suggests that stockpiled annual ryegrass could be used in the lower Midwest as a source of high‐quality winter forage for grazing livestock.

Tall fescue (Festuca arundinaceaSchreb.) infected with an endophyte that does not produce ergot‐like alkaloids (nontoxic endophyte) has not been evaluated for herbage mass, nutritive value, and ergovaline concentration when stockpiled during winter. Our objective was to quantify these responses for tall fescue infected with a native endophyte (K31 E+), a nontoxic endophyte (HiMag NTE), and with no endophyte (HiMag E−). Responses were measured on a fine, mixed, active, mesic Oxyaquic Fragiudalfs soil monthly from mid‐December through mid‐March in 1999‐2000 (Year 1) and 2000‐2001 (Year 2) in southern Missouri. Herbage mass for K31 E+ averaged 2370 kg ha−1, which was ≈20% greater than HiMag E− or HiMag NTE. Herbage mass did not change from mid‐December through mid‐March for any entry. The nutritive value of all entries was equal on comparable dates with acid detergent fiber (ADF) ranging from 285 to 338 g kg−1during the winter. Nutritive value was highest in mid‐December of each year and then declined slowly after that. Neither HiMag E− nor HiMag NTE contained ergovaline, but K31 E+ had substantial concentrations of ergovaline in both years. The ergovaline concentration of K31 E+ was 454 μg kg−1in December of Year 1 and 175 μg kg−1in December of Year 2, but declined by ≈85% by March each year. The stable herbage mass, slowly declining nutritive value, and absence of ergovaline in HiMag E− and HiMag NTE suggest that livestock producers could eliminate toxicosis problems by stockpiling these forages for winter grazing.

Condensed tannins in forage legumes can be beneficial or detrimental to ruminant livestock performance, depending on concentration. The objective of this research was to determine condensed tannin concentration in birdsfoot trefoil (Lotus corniculatusL.) without rhizomes (BFT) and with rhizomes (RBFT) from grazed monocultures and mixtures. An additional objective was to investigate possible fluctuation of condensed tannin concentrations through the spring grazing season. In 1997, ‘Norcen’ BFT and ‘ARS‐2620’ RBFT were sown into pastures located at Columbia, MO; pastures were pure stands or mixtures with tall fescue (TF; Festuca arundinaceaSchreb). Pastures were grazed in 1998 and 1999, and the BFT and RBFT components were hand clipped every 14 d throughout the spring of 1998 and 1999. Samples were analyzed for condensed tannin concentration by near infrared (NIR) reflectance spectroscopy with calibrations based on the vanillin−HCl colorimetric method. Condensed tannin concentrations of grazed BFT were lower in this study than concentrations reported in other studies. Averaged over both years, BFT contained 11.4 g catechin equivalents (CE) kg−1DM, and RBFT contained (P< 0.05) three times that amount (38.6 g CE kg−1DM). Also, condensed tannin concentrations of the BFT component were 100% higher when BFT was grown in a mixture instead of a pure stand (P< 0.10); in 1999, they were 55% higher (P< 0.05). Finally, condensed tannin concentration fluctuated over the spring of 1998 (P< 0.05), but not the spring of 1999. We concluded that condensed tannins in BFT are much lower than in RBFT, that condensed tannins in BFT decrease when grown with a tall fescue companion grass, and that concentrations can fluctuate in the spring as they do in the autumn.

This study investigated the performance of steers grazing rhizomatous birdsfoot trefoil (Lotus corniculatusL.) (RBFT) compared to nonrhizomatous birdsfoot trefoil (BFT) in pure stands or when interseeded with endophyte-free tall fescue (Festuca arundinaceaSchreb.; TF). Five forage treatments of RBFT, BFT, TF, RBFT+TF, and BFT+TF (four replicate paddocks per treatment) were continuously stocked in spring and fall of 1998 and spring of 1999. Grazing for individual treatments was terminated when pasture mass fell below 900 kg/ha. Average daily gain was greatest (P< 0.10) in pure stands of BFT and RBFT, but total forage production, and thus grazing days, for these treatments was low. Average daily gain for steers grazing BFT+TF and RBFT+TF treatments was not different from (spring and fall 1998) or greater (P< 0.10) (spring 1999) than that for TF. Total forage production of BFT+TF and RBFT+TF was greater (P< 0.10) than that of TF in spring 1998. In fall 1998, BFT+TF produced more (P< 0.10) total forage than either RBFT+TF or TF, and in spring 1999, RBFT+TF had less (P< 0.10) total forage than TF or BFT+TF. Total steer days on mixed pastures were greater (P< 0.10) than that for TF in spring and fall 1998 but not different from those for TF in spring 1999. In all three trials total weight gain/hectare was greater (P< 0.10) for RBFT+TF and BFT+TF than for TF. The RBFT+TF and BFT +TF had greater (P< 0.05) CP than TF in spring and fall 1998 and less (P< 0.05) NDF and ADF in fall 1998. We concluded that either RBFT or BFT could be interseeded with tall fescue to enhance ADG and total steer days.

Observations of cosmic rays and their related radio to gamma-ray signatures are surveyed and discussed critically, and compared to theoretical models of the cosmic-ray origin and propagation. The analogous heliospheric processes are included as a well-studied case of the principal physical processes of energetic particle acceleration and propagation. Reinforcements, or conflicts, in the interpretations of cosmic-ray spectral and compositional characteristics arise when cosmic-ray source and propagation models are confronted with astronomical information about the Galaxy as a whole and from potential source sites, i.e., supernova remnants or regions with high massive-star density. This volume represents the outcome of two workshops held at ISSI. In this chapter we summarize the introductory papers presented below, and include insights from the workshop discussions.

Measurements of the composition and spatial distribution of pick-up ions inside the heliosphere are reviewed. The first interstellar 4He+pick-up ions were detected with the SULEICA instrument on the AMPTE spacecraft near Earth's orbit. Most data on pick-up ions were taken in the solar-wind and suprathermal energy range of SWICS on Ulysses while the spacecraft cruised from 1.4 to 5.4 AU and explored the high-latitude heliosphere and solar wind from the ecliptic to ± 80°heliolatitude. This includes the discovery of H+, 4He++, 3He+, N+,O+, and Ne+pick-up ions that originate from the interstellar neutralgas penetrating the heliosphere. From their fluxes properties of the interaction region between the heliosphere and the Local Interstellar Cloud such as the limits on filtration and the strength of the interstellar magnetic field have been revealed. Detailed analysis of the velocity distributions of pick-up ions led to 1) the discovery of a new distinct source, the so-called Inner Source, consisting of atoms released from interstellar and interplanetary dust inside the heliosphere, 2) the determination of pick-up ion transport parameters such as the long mean free path for pitch-angle scattering of order1 AU, and 3) detailed knowledge on the very preferential injection and acceleration of pick-up ions during interplanetary energetic particle events such as Co-rotating Interaction Regions and Coronal Mass Ejections. SWICS measurements have fully confirmed the theory of Fisk, Koslovsky, and Ramaty that pick-up ions derived from the interstellar gas are the dominant source of the Anomalous Cosmic Rays; they are pre-accelerated inside the heliosphere and re-accelerated at the solar-wind Termination Shock according to Pesses, Eichler, and Jokipii. The data indicate that the Inner Source of pick-up ionsis largely responsible for the occurence of C+in the Anomalous Cosmic Rays. The abundances of recently discovered Inner-Source Mg+and Si+are solar-wind like and consistent with their abundances in the energetic particles associated with Co-rotating Interaction Regions. Knowledge on the injection and acceleration processes in Co-rotating Interaction Regions is applied to discuss the current observational evidence for the Interplanetary Focusing Cone of the interstellar neutral gas due to the Sun's gravitational force. The 25–150 keV/amu suprathermal 4He+pick-up ion fluxes measured by CELIAS/STOF on board SOHO over 360°of ecliptic longitude represent a `local' ionization and acceleration of interstellar atoms at 1 AU or smaller heliocentric distances. Completing the first limited data set of SULEICA/AMPTE on 4He+pick-up ions they indicate a density enhancement in the Interplanetary Focusing Cone which is confirmed by recent SWICS/ACE data. Clear evidence for signatures in ecliptic longitude are found in the data on energetic neutral H fluxes observed with the CELIAS/HSTOF sensor on board SOHO. These fluxes are enhanced in the upstream and downstream directions of the interstellar wind. Detection of energetic H atoms, which propagate unaffected by the Heliospheric Magnetic Field, provided for the first time a diagnostic tool for observations near Earth to analyze the structure in ecliptic longitude of the interface region between the heliosphere and the Local Interstellar Cloud.

On the basis of the observational picture established in the report of Mason, von Steiger et al.(1999) the status of theoretical models on origin, injection, and acceleration of particles associated with Corotating Interaction Regions (CIRs) is reviewed. This includes diffusive or first-order Fermi acceleration at oblique shocks, adiabatic deceleration in the solar wind, stochastic acceleration in Alfvén waves and oblique propagating magnetosonic waves, and shock surfing as possible injection mechanism to discriminate pickup ions from solar wind ions.

This report emphasizes new observational aspects of CIR ions revealed by advanced instruments launched on the Ulysses, WIND, SOHO, and ACE spacecraft, and by the unique vantage point of Ulysses which carried out the first survey of Corotating Interaction Region (CIR) properties over a very wide range of heliolatitudes. With this more complete observational picture established, this review is the basis to consider the status of theoretical models on origin, injection, and acceleration of CIR particles reported by Scholer, Mann et al.(1999) in this volume.

Corotating Interaction Regions (CIRs) form as a consequence of the compression of the solar wind at the interface between fast speed streams and slow streams. Dynamic interaction of solar wind streams is a general feature of the heliospheric medium; when the sources of the solar wind streams are relatively stable, the interaction regions form a pattern which corotates with the Sun. The regions of origin of the high speed solar wind streams have been clearly identified as the coronal holes with their open magnetic field structures. The origin of the slow speed solar wind is less clear; slow streams may well originate from a range of coronal configurations adjacent to, or above magnetically closed structures. This article addresses the coronal origin of the stable pattern of solar wind streams which leads to the formation of CIRs. In particular, coronal models based on photospheric measurements are reviewed; we also examine the observations of kinematic and compositional solar wind features at 1 AU, their appearance in the stream interfaces (SIs) of CIRs, and their relationship to the structure of the solar surface and the inner corona; finally we summarise the Helios observations in the inner heliosphere of CIRs and their precursors to give a link between the optical observations on their solar origin and the in-situ plasma observations at 1 AU after their formation. The most important question that remains to be answered concerning the solar origin of CIRs is related to the origin and morphology of the slow solar wind.

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The Solar Wind Ion Composition Spectrometer (SWICS) and the Solar Wind Ions Mass Spectrometer (SWIMS) on ACE are instruments optimized for measurements of the chemical and isotopic composition of solar and interstellar matter. SWICS determines uniquely the chemical and ionic-charge composition of the solar wind, the thermal and mean speeds of all major solar wind ions from H through Fe at all solar wind speeds above 300 km s−1 (protons) and 170 km s−1 (Fe+16), and resolves H and He isotopes of both solar and interstellar sources. SWICS will measure the distribution functions of both the interstellar cloud and dust cloud pickup ions up to energies of 100 keV e−1. SWIMS will measure the chemical, isotopic and charge state composition of the solar wind for every element between He and Ni. Each of the two instruments uses electrostatic analysis followed by a time-of-flight and, as required, an energy measurement. The observations made with SWICS and SWIMS will make valuable contributions to the ISTP objectives by providing information regarding the composition and energy distribution of matter entering the magnetosphere. In addition, SWICS and SWIMS results will have an impact on many areas of solar and heliospheric physics, in particular providing important and unique information on: (i) conditions and processes in the region of the corona where the solar wind is accelerated; (ii) the location of the source regions of the solar wind in the corona; (iii) coronal heating processes; (iv) the extent and causes of variations in the composition of the solar atmosphere; (v) plasma processes in the solar wind; (vi) the acceleration of particles in the solar wind; (vii) the physics of the pickup process of interstellar He in the solar wind; and (viii) the spatial distribution and characteristics of sources of neutral matter in the inner heliosphere.

Using the high-resolution mass spectrometer MTOF on board SOHO we have measured the solar wind isotopic abundance ratios of Ne, Mg, and Si in different solar wind regimes with bulk velocities ranging from 350 km/s to 650 km/s. Data indicate a systematic depletion of the heavier isotopes in the slow solar wind compared to their abundances in the fast solar wind from coronal holes. These variations in the solar wind isotopic composition represent a pure mass-dependent effect because the different isotopes of an element pass the inner corona with the same charge state distribution. The influence of particle mass on the acceleration of minor solar wind ions is discussed in the context of theoretical models and recent optical observations with other SOHO instruments.

Sainfoin (Onobrychis viciifoliaScop.) often exhibits poor growth following periods of high ambient temperatures. Our objective was to investigate the influence of air and soil temperature on regrowth and persistence of sainfoin. At 99 d post planting, ‘Renumex’ sainfoin grown in 5‐ by 40‐cm tubes were placed into growth chambers. Treatments were chamber air temperatures of 15, 25, or 35°C with soil temperatures of 10, 20, or 30°C. After a 21‐d adjustment period, all plants were clipped to 2 cm (Harvest 1). Plants regrew for 35 before the final harvest (Harvest 2). Measurements were number of leaves, leaf area, shoot mass, taproot mass, fine root mass, crown mass, taproot carbohydrates, tarch degrading enzyme activity, whole plant metabolism, and plant survival. Leaves per plant decreased with increasing air temperature and this caused a decrease in sainfoin leaf area per plant and shoot yield per plant. Increasing air temperature from 15 to 35°C or soil temperature from 10 to 30°C decreased crown, taproot, and fine root mass by as much as 98%. Concentration of taproot carbohydrates showed a negative correlation (P< 0.05) with increasing air temperature. Metabolic rates of leaves and roots were two and five times higher, respectively, when the air or soil temperature increased by 20°C. Increasing air temperature showed a positive correlation (P< 0.05) with the number of dead plants per treatment (R2= 0.90). Few plants grown at 35°C survived. Severe defoliation during periods of high temperatures may cause plant death because high metabolic rates cannot be supported by existing leaf area or taproot carbohydrate

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The CELIAS experiment on SOHO is designed to measure the mass, ionic charge and energy of the low and high speed solar wind, of suprathermal ions, and of low energy flare particles. Through analysis of the elemental and isotopic abundances, the ionic charge state, and the velocity distributions of ions originating in the solar atmosphere, the investigation focuses on the plasma processes on various temporal and spatial scales in the solar chromosphere, transition zone, and corona. CELIAS includes 3 mass- and charge-discriminating sensors based on the time-of-flight technique: CTOF for the elemental, charge and velocity distribution of the solar wind, MTOF for the elemental and isotopic composition of the solar wind, and STOF for the mass, charge and energy distribution of suprathermal ions. The instrument will provide detailed in situ diagnostics of the solar wind and of accelerated particles, which will complement the optical and spectroscopic investigations of the solar atmosphere on SOHO. CELIAS also contains a Solar Extreme Ultraviolet Monitor, SEM, which continously measures the EUV flux in a wide band of 17 – 70 nm, and a narrow band around the 30.4 nm He II line.

The High-Energy Suprathermal Time-of-Flight sensor (HSTOF) of the Charge, Element, and Isotope Analysis System (CELIAS) on the SolarandHeliosphericObservatory(SOHO) near the Lagrangian point L1 is capable of identifying energetic hydrogen atoms (EHAs) between 55 and 80 keV. Between 1996 February 13 and 1997 August 31, near solar minimum, there were 285 "quiet" days when the interplanetary charged-particle flux was low. During these quiet times, HSTOF scanned the apex of the heliosphere once and the antiapex twice. The flux level and time profile, and hence the arrival direction, of the EHAs accumulated during these quiet times are best interpreted as fluxes of EHAs coming from the heliosheath.

Sainfoin's (Onobrychis viciifoliaScop.) poor growth following defoliation and lack of stand persistence have limited producer acceptance. Because sainfoin growth is poorest in the summer when the daylengths are longest, daylength influence on regrowth and persistence was investigated. Forty, 130‐d‐old (±4 d) ‘Renumex’ sainfoin plants were placed in growth chambers under daylengths of 10, 13, and 16 h of light daily. After a 14‐d adjustment period, plants were clipped to 2 cm. Clipped plants were allowed to regrow for 35 d (Harvest 1) clipped again and allowed to regrow for 14 additional days before final harvest (Harvest 2). Plant height, number of blooms, number of leaves, leaf area, and shoot dry mass were measured before each clipping and at final harvest (Harvest 2). Mass of taproots, fine roots and crowns as well as taproot reducing sugars, total sugars, and total nonstructural carbohydrate (TNC) were determined at Harvest 2. Activity of starch degrading enzymes and whole plant metabolism was measured at Harvest 2. Although daylength had some effects on sainfoin growth form (i.e., plant height and reproductive structures), the vegetative growth of sainfoin was otherwise unaltered by daylength (P> 0.05). Fine root mass was 38% (0.33 g plant−1) greater (P< 0.05) in the 16‐h treatment than in the 10‐h treatment. Taproot carbohydrates, starch enzyme activity, and metabolic heat rates were not altered by daylength (P> 0.05). Our results show that factors other than daylength regulate sainfoin growth after defoliation.

Using the high-resolution mass spectrometer CELIAS/MTOF on board SOHO we have measured the solar wind isotope abundance ratios of Si, Ne, and Mg and their variations in different solar wind regimes with bulk velocities ranging from 330 km/s to 650 km/s. Data indicate a small systematic depletion of the heavier isotopes in the slow solar wind on the order of (1.4±1.3)% per amu (2σ-error) compared to their abundances in the fast solar wind from coronal holes. These variations in the solar wind isotopic composition represent a pure mass-dependent effect because the different isotopes of an element pass the inner corona with the same charge state distribution. The influence of particle mass on the acceleration of minor solar wind ions is discussed in the context of theoretical models and recent optical observations with other SOHO instruments.