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Tall fescue (Schedonorus arundinaceus (Shreb.) Dumort) is a cool-season forage grown in the mid-south United States of America that has the potential for spring silage. Ergovaline produced by the fungal endophyte Neotyphodium coenophialum is preserved in tall fescue silage and can induce tall fescue toxicosis in livestock. Condensed tannins, such as quebracho (Schinopsis quebracho-colorado (Schltdl.) F.A. Barkley and T. Meyer) extract, can bind to the nitrogenous components of ergovaline, rendering it ineffective in the ruminant. Quebracho tannin (QT) can also bind to crude protein, reducing its conversion to ammonia. Quebracho tannin was either not added (0QT) or added at 10 (10QT) or 20 (20QT) g/kg of dry matter (DM) of silage to chopped endophyte-infected tall fescue of 670 g/kg of moisture (high moisture, HM) and 440 g/kg of moisture (low moisture, LM). A moisture × QT interaction affected the final pH (p = 0.02), with the lowest pH observed in HM silages with 0QT and 10QT. The ergovaline concentrations were not significantly different (p = 0.19) among the post-ensiled forages. Ammonia concentrations (g/kg DM) were affected by a moisture × QT interaction (p = 0.05), with greater concentrations observed in HM 0QT compared with HM 10QT, HM 20QT, and LM 20QT. Lactic acid concentrations (g/kg DM) decreased (p = 0.05) with the addition of QT. The moisture × QT interaction (p = 0.02) resulted in higher concentrations of acetic acid in the HM silages with 0QT and 20QT compared to the LM silage with 20QT. The total acid concentrations (g/kg DM) were higher (p < 0.01) at HM but did not differ (p = 0.54) across the QT concentrations. Ensiling tall fescue with quebracho tannin did not reduce the ergovaline concentrations, although proteolysis was reduced at the inclusion of 10 g/kg of QT in the HM silages and 20 g/kg of QT in the LM silages. The results indicate that QT as a tall fescue silage additive showed promise for modifying silage characteristics but it did not reduce ergovaline concentrations at the low QT levels used in this study.

Forage management and environmental conditions affect water soluble carbohydrate (WSC) storage, and, in turn, influence ruminant forage utilization in silvopastoral systems. The objective was to determine effects of four dependent variables: forage species [(non-native, C3 (orchardgrass (Dactylis glomerata L.)) and native C4 mix (8:1:1 big bluestem (Andropogon gerardii Vitman), little bluestem (Schizachyrium scoparium Michx. Nash) and indiangrass (Sorghastrum nutans L.))], fertility (poultry litter and an unfertilized control), forage sampling date (mid-May, late-May, early-June, mid-June, and late-June), and hour of day (0800, 1100, 1400, and 1700 h) on WSC accumulation in a silvopasture. Concentrations of WSC (g kg DM−1) were greater (p ≤ 0.05) for C3 forages, with poultry litter not impacting WSC accumulation. Overall, WSC was greatest in mid-June, with the lowest WSC concentration observed at 0800 compared to 1100, 1400, and 1700 h (p ≤ 0.05). Therefore, harvesting forages later in the day resulted in greater WSC. A stepwise regression model indicated acid detergent fiber, ash, and forage P concentration were the best predictors (R2 = 0.85, p ≤ 0.05) of forage WSC. These results may be useful in future studies aimed at explaining diurnal cattle grazing preference and optimum forage harvest timing in silvopastoral systems.

Moisture concentration and time between baling and wrapping round bale silage impacts silage quality and aerobic stability. The objective of this study was to observe the effects of wrapping delays of 0, 1, 2, or 3 days on the nutritional quality and storage characteristics of annual ryegrass (Lolium multiflorum) silage baled at two levels of moisture (30 ± 9.5% [DRY] or 74 ± 0.8% [WET]). The DRY (n = 18) and WET (n = 20) bales were assigned as replicates and wrapped by pasture quadrant, then stored for 85 d. Crude protein, ADF, NDF, and ADICP of silage were greater (P < 0.01) for DRY than WET. Wrapping delays did not change bale weight or CP , but DM concentrations decreased linearly (P = 0.03) and ADF, NDF, and ADICP increased (P = 0.02) linearly with wrapping delay. Maximum temperature of DRY was greater (P = 0.01) than WET and increased linearly with wrapping delays (P < 0.01). Changes in the fermentation profile of WET bales with delays in wrapping indicated clostridial activity occurred, which will likely result in reductions in voluntary intake by livestock. Based on these results, ryegrass fermentation patterns and nutritional quality show a decline with each day delayed before wrapping with WET silage.

(ProQuest: ... denotes formulae omitted.)Stakeholders in the cow-calf industry are under ongoing financial and regulatory pressure to revise production methods to improve their economic and environmental efficiency. Several studies estimated that cow-calf production practices commonly used in North America are the greatest source of greenhouse gas (GHG) emissions of all beef-cattle enterprises (Lupo et al. 2013,Beaucheminetal.2011, Pelletier, Pirog, and Rasmussen 2010). While methods for mitigating GHG emissions from cow-calf operations are needed (Beauchemin et al. 2011), such measures can reduce productivity and hence decrease profitability (Zilverberg et al. 2011). Furthermore, a combination of volatile input and commodity prices and increasing environmental regulation has created a need for tools by which producers can better evaluate various inputs and production methods when making decisions at the farm level. University of Arkansas created decision-support software, Forage and Cattle Planner (FORCAP), that producers, extension agents, and researchers can use to estimate net returns and changes in GHG emissions for different cow-calf and forage-management strategies and inputs (Popp et al. 2014). The FORCAP spreadsheet allows users to enter operation-specific parameters, inputs, and production methods to compare estimated net returns and GHG emissions in Excel®. The software and accompanying reference and user manuals are available online (Keeton et al. 2014, Smith, Popp, and Keeton 2013).In this analysis, we used FORCAP and an Excel® add-in, Risk Solver Platform v12.5 (Frontline Systems Inc.), to simulate profit-maximizing forage and cattle management decisions for medium and large size operations in a steady-state environment with no growth in herd size. The profit-maximizing model modified the species composition of pasture forage, the stocking rate, and weaning age for three calving distributions-spring, fall, and year-round- using three pasture-fertilization scenarios-none, low, and high-for each operation size, resulting in eighteen scenarios in all. This analysis examined the potential net returns and GHG emission tradeoffsbetweendifferent input selections and production decisions. For example, increasing pasture fertilization may be more profitable by allowing for a greater stocking rate but may lead to a higher environmental cost by way of both the increased number of animals and greater fertilizer emissions per acre. Conversely, it may be more profitable not to fertilize given the high cost of fertilizing, thus reducing GHG emissions from fertilizer and potentially reducing beef production and thereby animal emissions per acre. This analysis provides practical information about likely changes in beef production, profitability, and GHG emissions in response to modifications to pasture fertilization, calving distributions, pasture species composition, weaning age, and stocking rates.BackgroundChanges in the composition of pasture forage species can lead to seasonal forage growth that more closely matches the monthly nutritional requirements of the animals for a given calving season and weaning age. Further, inclusion of nitrogen-fixing species can reduce commercial nitrogen fertilizer requirements (West and Waller 2007) and hence reduce GHG emissions from upstream fertilizer production and nitrous oxide emissions from nitrogen that volatizes when such fertilizers are applied. However, inclusion of these nitrogen-fixing species may require additional production costs (Zilverberg et al. 2011).In Arkansas, pasture-forage species can be broadly categorized as warm-season grasses, cool-season grasses, and legumes. Warm-season grasses actively grow from late spring to late summer (May to August). Cool-season grasses typically grow from early spring to early summer (March to June) and are dormant during periods of high temperatures in mid-summer (July and August). These grasses typically resume growing in the fall (September to November) as temperatures decrease. …

In Arkansas, maximizing fall forage production from cereal grains is important for optimizing growth of fall-weaned calves (Bos taurus). Our objectives were to evaluate eight cultivars of wheat (Triticum aestivum L.), oat (Avena sativa L.), rye (Secale cereale L.), and triticale (x Triticosecale Wittmack) for their potential to accumulate fall forage dry matter (DM). At Fayetteville during 2004, triticale and oat cultivars accumulated DM in a cubic (P≤0.01) pattern over time, most likely because growing tillers exhibited stem elongation, and were then susceptible to freeze damage in late December. Wheat and rye cultivars accumulated DM in less complex patterns over harvest dates, but the maximum yield for any wheat cultivar was only 2554 kg ha -1 compared to 4661 kg ha -1 for oat. For Batesville 2004 and Fayetteville 2005, DM yields ranked similarly, but respective mean yields (491 and 988 kg ha -1 ) averaged over all harvest dates were only 25 and 50% of those for Fayetteville 2004 (1960 kg ha -1 ), largely due to drought. For Batesville 2005, growing conditions were somewhat unique relative to other site-years, and wheat, rye, and triticale cultivars accumulated an overall mean of 4148 kg ha -1 of forage DM on the final (4 January) harvest date. In contrast, oat cultivars were sensitive to freezing temperatures in November, and ranked last among all cultivars for yield on the final harvest date. Producers can usually improve fall forage production with cultivars that exhibit some stem elongation when planted in early September; however, this trait may make winter survival problematic.

Throughout the southern Ozark Highlands, endophyte-infected tall fescue (Lolium arundi- naceum (Schreb.) Darbysh) hay often is stored outdoors, without cover. At two research sites (Fayetteville and Batesville, AR), the effects of unprotected storage were assessed for large round bales of tall fescue hay packaged at three diameters (≈1.1, 1.4, and 1.7 m). Bales were stored over winter either inside or outside on wooden pallets and then sampled at three depths (0-0.15 m, 0.15-0.31 m, and 0.31-0.46 m). At both locations, bale diameter had no effect (p > 0.05) on dry matter (DM) recovery or nutritive value. Generally, there was little dete- rioration of nutritive value during the storage period, regardless of treatment; however, some interactions (p ≤ 0.041) of storage location and sampling depth were observed at each experi- mental site. Ruminal disappearance kinetics of DM exhibited some statistical differences (p ≤ 0.030) in response to treatment; however, their relative magnitude was generally small, and there was little evidence to suggest biologi- cal relevance. After storage, concentrations of ergovaline were not affected (p > 0.05) by baling treatment at Batesville (overall mean 256 μg kg −1 ); however, this was a 27.3% reduction from the initial concentration immediately after mowing. At Fayetteville this reduction was even greater, falling by 79.4% between standing forage (539 μg kg −1 ) and samples taken from baled hay after storage (111 μg kg −1 ). At both sites, bales stored outside on wooden pallets exhibited relatively small changes in nutritive value, disappearance kinetics, and ergovaline at the bale surface rela- tive to the internal portions of the bale.

The economic impact of rotation frequency (twice weekly vs. twice monthly until time of weaning) and time of weaning (early April vs. 56 d later) was examined for fall-calving cows using a modified put and take grazing strategy implemented to maintain equal grazing pressure across production systems. Cow and/or calf death losses resulted in replacements with either bred cows or cow-calf pairs. While the analysis on heifer calves was limited to sale at time of weaning, steer calves were tracked through the feedlot stage to determine if the time of sale would alter production system recommendations. For the conditions presented in this study, cow-calf producers may be advised that (i) relative to late weaning, early weaned calves did not regain their weight disadvantage observed at time of weaning; (ii) more intensive pasture management (rotating twice weekly rather than twice monthly) was not worth the effort because partial return results for late-weaned steer and heifer calves did not differ statistically by rotation frequency, regardless of sale time; (iii) partial returns were highest for steer calves retained through the finishing stage at the feedlot (regardless of production system) compared with sale at the time of weaning or at the time of placement in the feedlot; (iv) the range of returns or financial risk exposure increased with length of calf ownership. However, use of long-term average prices excluded input price risk from the analysis and output price risk was only partially addressed.

A 4-yr trial was initiated in January 2000 to evaluate cow-calf performance on mixed-species pasture systems consisting of (i) endophyte-infected tall fescue (E+; Festuca arundinacea Schreb.) diluted by approximately 50% with common bermudagrass [Cynodon dactylon (L.) Pers.] and other forages; (ii) endophyte-free tall fescue (E-) overseeded into dormant common bermudagrass; and (iii) orchardgrass (OG; Dactylis glomerata L.) established under the same conditions as E-. The E- and OG pastures were grazed with either twice weekly (2W) or twice monthly (2M) rotation schedules, while pastures with E+ were grazed with 2M only. Actual weaning weights tended to be greater (P = 0.096), and age-adjusted 205-d weaning weights and average daily gain from birth to weaning were greater (P ≤ 0.035) for calves raised on low-toxicity (E - or OG) pastures compared to those raised on E+. Over 4 yr, calves raised on low-toxicity pastures exhibited 22- and 24-kg advantages in actual and 205-d adjusted weaning weights, respectively, compared to those raised on E+. Cows grazing OG and E- pastures exhibited greater (P ≤ 0.021) body weights and body condition scores (BCS) at calving than cows grazing E+ pastures. Furthermore, reductions in body weight and BCS between calving and weaning tended to be greater (P ≤ 0.088) for cows grazing E+ pastures. Calf performance was improved consistently by these low-toxidty pasture systems, but management requirements may limit adaptation by producers.

A systems trial was designed to evaluate forage characteristics within mixed-species pastures consisting of (i) endophyte-infected tall fescue (Festuca arundinacea Schreb.; E+) mixed with common bermudagrass [Cynodon dactylon (L.) Pers.] and other forages; (ii) endophyte-free tall fescue (E-) overseeded into dormant common bermudagrass; and (iii) orchardgrass (OG; Dactylis glomerata L.) established under the same conditions as E-. The E- and OG pastures were grazed with either twice weekly (2W) or twice monthly (2M) rotation schedules, but E+ was grazed only as 2M. Across 41 sampling dates (2000 through 2003) the mean forage mass across all forage systems was 3809 kg ha -1 , and there was an interaction of forage system and sampling date (P = 0.001). In vitro dry matter disappearance (IVDMD) and crude protein (CP) varied (P < 0.0001) with sampling date in seasonal patterns that were generally predictable. Frequencies of tall fescue in E- and E+ pastures increased (P < 0.10) over years, reaching numerical maxima (61 to 72%) at the end of the trial. For OG, frequencies reached numerical maxima of 52 and 42% in 2W and 2M pastures, respectively, but then declined (P < 0.10) over time, ending at 39 and 24%, respectively. At the end of the trial, reinfection of OG pastures by rogue E+ plants reached a numerical maximum frequency of only 10%, and concentrations of total ergot alkaloids in tall fescue plants from E- pastures were only about 25% of those for E+ pastures, thereby suggesting that pasture toxicity can be reduced substantially for at least 5 yr using these alternative forage systems.

‘Common’ and ‘Tifton 44’ bermudagrass [Cynodon dactylon (L.) Pers.] located near Fayetteville and Batesville, AR, respectively, were chosen to evaluate the effects of stockpiling initiation date (August or September), and N fertilization rate (0, 37, 74, or 111 kg N ha 21 )o n the nutritive value of fall-stockpiled bermudagrass. At the Fayetteville location, there were initiation 3 harvest date interactions for acid detergent fiber (ADF, P 5 0.003), hemicellulose (P 5 0.003), cellulose (P 5 0.0003), lignin (P 5 0.007), and crude protein (CP, P 5 0.008) in 2000, and strong interactions (P # 0.001) for all response variables in 2001. Generally, neutral detergent fiber (NDF), ADF, cellulose, and lignin increased over harvest dates for both initiation dates in 2000, although increases for lignin were only numerical (P . 0.05) for the September initiation date. Similar responses were observed for the August initiation date in 2001, but fiber components for the September 2001 initiation date declined over time because of contamination by other winter-annual species. For August initiation dates in 2000 and 2001, in vitro organic matter disappearance (IVOMD) declined linearly (P # 0.002) over harvest dates, reaching respective minima of 330 and 361 g kg 21 . At the Batesville site, an N fertilization effect (P # 0.017) was observed for NDF, ADF, and CP in both 2000 and 2001. A similar effect was observed for lignin (P 5 0.001) and IVOMD (P , 0.0001) in 2000, and for cellulose (P 5 0.0004) during 2001. Fertilization with N at the initiation of stockpiling generally reduced fiber components, and increased CP; however, IVOMD was increased for 2000 only. As observed for the Fayetteville site, most fiber components increased over harvest dates, while IVOMD declined concomitantly. Generally, the nutritive value of stockpiled bermudagrass declines between mid-October and mid-December, and spring-calving beef cows in the Upper South may need to be supplemented with energy to maintain body condition in the late fall or early winter.

This study investigated the effects of simulated rainfall on N partitioning and concentrations of degradable (DIP) or undegradable (UIP) intake protein for wilting orchardgrass (Dactylis glomerata L.) and bermudagrass [Cynodon dactylon (L.) Pers.] hays. Orchardgrass forage was wilted to 674, 153, or 41 g kg 21 of moisture (WET-O, IDEAL-O, and DRY-O, respectively) in the field before applying the simulated rainfall (0, 13, 25, 38, 51, 64, or 76 mm). For WET-O, DIP (g kg 21 crude protein [CP]) increased cubically (P 5 0.020) with simulated rainfall, but the overall range of response was small (653–673 g kg 21 CP). Estimates of DIP (g kg 21 CP) for IDEAL-O and DRY-O decreased by 46 and 25 g kg 21 CP, respectively, between the 0and 76-mm rainfall increments; for IDEAL-O, these decreases occurred in a linear (P , 0.0001) pattern, whereas quadratic (P 5 0.009) and linear (P 5 0.029) effects were observed for DRY-O. Bermudagrass forage was field wilted to 761, 400, or 130 g kg 21 of moisture (WET-B, MID-B, and IDEAL-B, respectively) and evaluated similarly. For WET-B and MID-B, DIP (g kg 21 CP) was not affected (P . 0.05) by simulated rainfall. In contrast, quartic (P 5 0.019) and linear (P 5 0.002) effects were observed for IDEAL-B, but these responses were confined primarily to changes between the undamaged (0-mm) control and the initial 13-mm rainfall increment. On a practical basis, concentrations of DIP were, at most, altered only moderately in response to simulated rainfall and relatively little when forages were still too wet to bale.

Throughout much of the southeastern USA, hay harvest can be complicated by a high probability of rainfall events that may cause damage to the resultant hay crop. The objectives of this study were to investigate the effects of simulated rainfall and two postrainfall drying methods on losses of dry matter (DM) and changes in nutritive value for wilting orchardgrass (Dactylis glomerata L.) and bermudagrass [Cynodon dactylon (L.) Pers.] forages. Orchardgrass was wilted to moisture concentrations of 674 (WET), 153 (IDEAL), and 41 (DRY) g kg - 1 and subjected to 0,12, 25, 38, 51, 64, or 76 mm of simulated rainfall from a custom-built rainfall simulator. For IDEAL orchardgrass, DM loss reached a maximum of 88 g kg - 1 when 76 mm of simulated rainfall was applied. Dry matter loss, total N, and all fiber components except hemicellulose increased with rainfall amount, exhibiting single or multiple polynomial effects (P ≤ 0.048) in each case; however, responses were not consistent across these response variables. A second study was conducted with bermudagrass using similar techniques, except that the forage contained 761 (WET), 400 (MID), and 130 (IDEAL) g kg - 1 of moisture when simulated rainfall was applied. For IDEAL bermudagrass forage, DM losses increased in linear (P = 0.001) and quadratic (P = 0.003) relationships with simulated rainfall, but the maximum DM loss was only 21 g kg - 1 . For both forages, DM loss and deleterious changes in nutritive value generally increased with rainfall amount, but these responses appeared to be much greater for orchardgrass.

Previous methodologies to measure losses of dry matter (DM) in wilting hays subjected to natural or simulated rainfall have relied generally on gravimetric techniques, resulting in variable and questionable estimates of DM loss. The objective of this study was to evaluate the use of fiber components and acid detergent insoluble ash (ADIA) as internal plant markers for accurately predicting losses of DM in bermudagrass [Cynodon dactylon (L.) Pers.] and orchardgrass (Dactylis glomerata L.) forages that were damaged by simulated rainfall. For both forages, concentrations of neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HEMI), cellulose (CELL), lignin, and ADIA generally increased with the amount of simulated rainfall in primarily linear patterns. Recoveries of all internal markers were high (≥952 g kg -1 ) and were not affected by simulated rainfall for either forage (P ≥ 0.06). Predicted losses of DM increased in primarily linear patterns with simulated rainfall for both forages when concentrations of NDF, ADF, HEMI, CELL, and ADIA were used as internal markers. Linear regressions of predicted losses of DM on values determined gravimetrically were good (r 2 ≥ 0.73; P ≤ 0.03) when concentrations of any fiber constituent or ADIA were used to calculate losses of DM; however. NDF was an especially effective internal marker (Y = 1.12X - 5; r 2 = 0.97; P < 0.01).

Autumn stockpiling is a management technique in which forage is allowed to accumulate throughout the late summer and early fall for subsequent grazing throughout the late fall and winter. Well-established stands of common and 'Tifton 44' bermudagrass [Cynodon dactylon (L.) Pers.] located at Fayetteville and Batesville, AR, respectively, were chosen to evaluate the effects of stockpiling initiation date (August or September) and N fertilization rate (0, 37, 74, or 111 kg N ha -1 ) on the canopy height and dry matter (DM) yield potential of autumn-stockpiled bermudagrass forage. Within year, DM yield increased linearly (P ≤ 0.008) with N fertilization rate at Fayetteville in 2001 and in Batesville during both years. For August initiation dates, DM yield declined linearly (P ≤ 0.007) with harvest date at both sites during both years; however, cubic responses (P ≤ 0.024) also were observed at both sites in 2000 but not (P ≥ 0.076) in 2001. For September initiation dates, DM yield exhibited less consistent patterns over harvest dates, but responses were cubic (P ≤ 0.053) over time for all four site-years. Tests of homogeneity for regressions of DM yield on canopy height for individual site-years indicated there were differences for the intercepts (P < 0.001) and linear coefficients (P < 0.001) and a tendency for the quadratic coefficients (P = 0.063) to differ. Quadratic equations are not suitable for producer use; therefore, a combined linear model for all data (N = 512) was determined, Y = 146x - 838 (P < 0.001; r 2 = 0.762), which may address the need for a quick estimator of available forage.

Relatively little is known about storage of wet (>200 g kg -1 moisture) bermudagrass [Cynodon dactylon (L.) Pers.] hay. Our objective was to assess the changes in nutritive value of bermudagrass hay as a function of hay moisture, storage time, and spontaneous heating. Greenfield' bermudagrass was grown on a Pickwick silt loam soil (fine-silty, mixed, semiactive, thermic Typic Paleudult) and packaged in conventional rectangular bales at 219, 265, and 302 g kg -1 moisture [low-moisture (LM), medium-moisture (MM), and high-moisture (HM) bales, respectively]. Concentrations of most fiber and fiber-associated N components increased (P 200 g kg -1 moisture deteriorates during storage, and the greatest deterioration occurs during the first 12 d after baling.

Estimates of rumen degradable or escape N are an important component of current nutritional models for feeding livestock, but attempts to estimate these fractions for bermudagrass [Cynodon dactylon (L.) Pers. have been limited, and the relationship between concentrations of these fractions and spontaneous heating during bale storage has not been evaluated. The objectives of this study were to (i) assess the relationship between rumen escape or degradable N and spontaneous heating in bermudagrass hays harvested from the same site during 1998 and 1999 and (ii) correlate estimates of rumen escape and degradable N with other measures of forage nutritive value that are evaluated commonly. A preparation of Streptomyces griseus protease was utilized in an in vitro laboratory procedure to quantify rumen degradable N in hays that heated spontaneously during storage in small haystacks. Maximum temperatures in these bales ranged from 37.1 to 69.8°C over 2 yr. Rumen escape N for 40 hays ranged from 407 to 613 g kg -1 N and increased linearly (P 0.05) for specific harvest years.

Conserving hay at moisture concentrations 200 g kg 1 is known to cause spontaneous heating and negative effects on forage nutritive value. While these relationships have been evaluated extensively for alfalfa (Medicago sativa L.), less research has evaluated these factors in warm-season grasses, specifically bermudagrass [Cynodon dactylon (L.) Pers.]. In this study, Greenfield' bermudagrass was grown on a Pickwick silt loam soil (fine-silty, mixed, semiactive, thermic Typic Paleudult) and packaged in conventional rectangular bales at five concentrations of moisture (178, 208, 248, 287, and 325 g kg ') and at high and medium bale densities (overall means = 208 and 186 kg m 3 , respectively). Bale density had little effect on forage nutritive value after storage. Furthermore, hale density had no effect (P > 0.05) on indices of spontaneous heating (heating degree days 35°C, maximum temperature, and 30-d average temperature), visual evalualion of mold, and dry matter (DM) recovery. Positive linear relationships occurred between concentrations of fibrous forage components and indices of spontaneous heating; coefficients of determination (r 2 ) statistics were similar for each index of spontaneous heating that was used as the independent variable in these linear regressions. Concentrations of acid detergent insoluble N and neutral detergent insoluble N expressed on a DM basis were positively related to measures of spontaneous heating in close linear relationships (r 2 ≥ 0.80). Regressions of other N fractions on measures of spontaneous heating exhibited lower coefficients of determination, but generally had significant slopes. Results of this study indicate that N in bermudagrass is very susceptible to reductions in bioavailability through heat damage during bale storage, and that this damage is increased with increases in initial bale moisture.

Bermudagrass [Cynodon dactylon (L.) Pers.] is productive in summer but dormant for much of the year in the central USA. The grazing season for bermudagrass can be lengthened with fall-interseeded small grains, which provide forage for early-season grazing. We compared forage yield and quality of rye (Secale cereale L., two cultivars), wheat (Triticum aestivum L., three cultivars), and barley (Hordeum vulgare L., one cultivar) when interseeded into bermudagrass sod or grown in monoculture. Field plots of each small grain were harvested two to four times each season and analyzed for in vitro dry matter digestibility (IVDMD) and crude protein (CP). Cumulative forage production for early spring (growing degree days [GDD] 1000) production of barley was usually greater than that of rye, but wheat cultivars were more balanced in seasonal production. Total forage production among small grains was often similar within each system, but the monoculture system had an almost threefold advantage. Although cultivars varied for IVDMD in the monoculture system, comparisons of digestible dry matter (DDM) were more consistent among harvests. Early DDM production of barley was usually lowest among the species, but as high or higher than other species for ryes. Concentrations of CP were variable, but relative CP production and yield had similar trends. In this study, rye was the best-suited species for interseeding in bermudagrass for early-season forage in grazing systems.