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Forage for grazing and hay may be limited during drought years, necessitating alternative feeding options. Co-product feedstuffs, such as soybean hulls (SH), may be a more economical means to maintain cows through such conditions. The objective of this study was to determine if SH could be used to meet the majority of the energy demands for cows in late gestation when access to hay was restricted to 1 h daily. Eighty-six gestating, spring-calving cows (527 ± 7.5 kg initial BW; 4.3 ± 0.27 yr of age) were allocated to 1 of 6 groups for a 68-d study beginning December 6, 2012. Three groups were given ad libitum access to medium-quality bermudagrass [Cynodon dactylon (L.) Pers.] hay. The 3 remaining groups were offered 6.4 kg of SH/cow daily and allowed access to a very-poor-quality, mature, mixed-grass hay for only 1 h daily. Each group was housed in separate 2.02-ha dormant bermudagrass pastures. Birth weight and dystocia scores were recorded, and calf performance was monitored through weaning. Representative bales of each hay were weighed to determine total hay offered. Differences in BW and BCS, and changes in these measurements during the study, were minimal between treatments (P ≥ 0.53). Calf birth weight, weaning weight, BW/d of age at weaning, and birth-to-weaning ADG did not differ (P ≥ 0.11) between treatments. Therefore, SH may be used as the major dietary energy component for cows in late gestation having access to hay for only 1 h daily without having adverse effects on the cows or their subsequent calves.

Negative effects on cattle grazing tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] infected with the wild-type endophyte Neotyphodium coenophialum (E+) are well documented, but information about the carryover effects on weaned calves is limited. Our objective was to compare pre- and postweaning performance by spring-calving cows and calves grazing E+ with that by cows grazing a nontoxic endophyte–tall fescue association (NE+). Pregnant Gelbvieh × Angus crossbred cows (n = 136; 492 ± 19.2 kg of initial BW) were stratified by BW and age and allocated randomly to one of four 10-ha pastures in yr 1 (October 15) and one of eight 10-ha pastures in yr 2 (November 30). Pastures were allocated randomly before establishment to E+ or NE+. Cows remained on their assigned pastures until weaning in yr 2 but were removed from NE+ in the summer of yr 1 because of low forage mass. After weaning, calves grazed bermudagrass [Cynodon dactylon (L.) Pers.] followed by cool-season annual grasses. Cow BW and pregnancy rate, and calf weaning weight and preweaning gain were greater (P < 0.05) from NE+ versus E+. Weaning weight differentials were maintained throughout postweaning production phases, resulting in heavier HCW (P < 0.05) by steers and a tendency for greater (P < 0.10) subsequent calving rates by heifers. Therefore, replacing E+ with NE+ may improve preweaning cow and calf performance and heifer reproductive rates, but postweaning gains may not be affected by previous exposure to E+.

A total of 120 Gelbvieh × Angus crossbred heifers (552 ± 2.5 lb initial BW) grazed pastures of common bermudagrass [Cynodon dactylon (L.) Pers.] overseeded with wheat (Triticum aestivum L.) and annual ryegrass (Lolium multiflorum Lam.) for a 3-year study to compare the effect of seeding dates and tillage intensities on heifer growth performance. Half of the pastures were seeded in early September (Early) and half in mid October (Late). Within seeding date, half of the pastures were disked once (1×) and half were disked twice (2×) before seeding. Grazing began when forage mass reached approximately 2000 lb/acre and continued through 11 May 2002 (year 1), 25 April 2003 (year 2), and 10 May 2004 (year 3). Forage mass was greater from Early than from Late seeded pastures for 2 of the first 3 months of grazing resulting in 17-day earlier grazing initiation and approximately 165 lb less hay fed per heifer. Total body weight gain, or gain while grazing cool-season annuals did not differ between seeding dates or tillage intensities. Producers in the Mid South region with bermudagrass pastures may have considerable flexibility in their decisions as to when to seed annual forages and to what intensity they till their sod depending upon how soon they need available forage.

a b s t r a c t Bermudagrass (Cynodon dactylon (L.) Pers.) is commonly used for grazing and haying in the southern USA, but hay curing can be challenging due to frequent rainfall events dur- ing spring and early summer. An existing stand of 'Greenfield' bermudagrass was divided into 12 plots using a randomized complete block design with a 2×2 factorial treatment arrangement to evaluate the influence of a non-viable Lactobacillus-lactic acid preservative and moisture concentration at baling on chemical composition, intake by sheep, and in situ disappearance in cattle. At time of mowing, half of the plots in each block were either spray-treated (T) or not treated (U) with 81 mL/t forage dry matter (DM) of the preser- vative solution. Hay was then baled at target moisture concentrations of either 174 g/kg DM (L) or 267 g/kg DM (H). Maximum temperature and heating degree days were greater (P 0.10). Post-storage nutritive value was largely influenced by moisture treatments only. Intake and digestibility, and in situ DM dis- appearance of these same hays were determined using 16 wether lambs (43 ± 3.7 kg initial BW), or six ruminally cannulated cows (617 ± 3.5 kg initial BW), respectively. Dry matter intake by sheep was not affected by either treatment factor (P>0.05), but DM digestibil- ity and digestible DM intake were greater (P

Fertilizing bermudagrass (Cynodon dactylon L. Pers.) with N can produce large quantities of forage and increase plant N concentrations. Bermudagrass growing on a caged-layer manure-amended site was fertilized with ammonium nitrate at 4 rates (0, 56, 112, and 168 kg N/ha) approximately 1 mo before first and third harvests on May 30 and August 18, 2000, to determine in situ disappearance kinetics of N and neutral detergent insoluble N (NDIN). Five crossbred ruminally cannulated steers (BW = 422 ± 21.0 kg) were used to evaluate in situ disappearance kinetics in a randomized complete block design with a 2 × 4 factorial arrangement. Immediately soluble N (fraction A) and rate of N disappearance increased linearly (P

Background The effect of time of fecal sampling on the accuracy of acid-detergent insoluble ash (ADIA) and alkaline-peroxide lignin (APL) for the prediction of fecal output (FO) in cattle was evaluated. Eight ruminally cannulated cows (594 ± 35.5 kg) were allocated randomly to 4 bermudagrass [Cynodon dactylon (L.) Pers.] hay diets markedly different in crude protein concentration (79–164 g/kg) with 2 replicates per diet for 3 periods. Cows were offered hay individually at 20 g DM/kg of body weight daily in equal feedings at 08:00 and 16:00 h for a 10-d adaptation period followed by 5-d of total fecal collection. Fecal grab samples also were taken each day during the fecal collection period at 06:00, 12:00, 18:00, and 24:00 h either directly from the rectum or from freshly voided feces. Samples were composited within cow and time across the 5 d total fecal collection period. Additionally, forage, ort, and fecal samples were analyzed for concentrations of APL and ADIA. Results Fecal concentrations of ADIA and APL were not affected by sampling time (P ≥ 0.22), even though diet affected (P

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.

Southern crabgrass (Digitaria ciliaris [Retz.] Koel.) is often an undesirable species in field and forage crops, but visual observations suggest that livestock prefer it to many other summer forages. The objectives of this study were to assess the nutritive value of crabgrass sampled weekly between July 11 and August 22, 2001 and then to determine ruminal in situ disappearance kinetics of N and neutral detergent insoluble N (NDIN) for these forages. A secondary objective was to compare these kinetic estimates for crabgrass with those of alfalfa (Medicago sativa L.), bermudagrass (Cynodon dactylon [L.] Pers.), and or-chardgrass (Dactylis glomerata L.) as control hays. All kinetic evaluations were conducted with 5 ruminally cannulated Gelbvieh x Angus x Brangus steers (383 +/- 22.7 kg). Concentrations of N for crabgrass decreased linearly (P < or = 0.002) across sampling dates for leaf, stem, and whole-plant tissues. Conversely, percentages of the total N pool within NDIN and ADIN fractions generally increased over sampling dates in mostly linear patterns. For crabgrass, the immediately soluble portion of the total N pool (fraction A; overall mean = 54.6% of N) was greater (P < 0.001) than for all control hays. Crabgrass exhibited a more rapid N disappearance rate (overall mean = 0.093/h; expressed as a proportion disappearing/h) than that of bermudagrass (0.046/h; P < 0.001), but the disappearance rate for alfalfa N (0.223/h) was considerably faster (P < 0.001) than for crabgrass. The effective ruminal disappearance of N was greater (P < 0.001) for crabgrass (overall mean = 85.4%) than for the alfalfa (83.3%), bermudagrass (72.3%), or orchardgrass (76.0%) control hays. For alfalfa, the ruminal disappearance rate of NDIN (0.150/h) was more rapid (P < 0.001) than for crabgrass (overall mean = 0.110/h); however, the disappearance rate for crabgrass was faster than that for bermudagrass (0.072/h; P < 0.001) or for orchardgrass (0.098/h; P = 0.010). Effective ruminal disappearance of NDIN was greater (P < 0.001) for crabgrass (overall mean = 72.0%) than for the bermudagrass (69.0%) or alfalfa hays (50.5%), but there was no difference (P = 0.865) between crabgrass and orchardgrass (72.1%). Although crabgrass forages exhibited concentrations of total N that were comparable with those of alfalfa and rates of ruminal N disappearance that were < 50% of those for the alfalfa hay control, improvements in N use efficiency relative to alfalfa are questionable because of the excessively large Fraction A for crabgrass.

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.

Southern crabgrass (Digitaria ciliaris [Retz.] Koel.) is often viewed as an undesirable weed, largely because it encroaches upon field and forage crops, gardens, and lawns. However, visual observations of livestock grazing mixed-species pastures suggest that cattle seem to prefer crabgrass to many other summer forages. The objectives of this study were to assess the nutritive value of crabgrass sampled weekly between July 11, and August 22, 2001, and then to determine ruminal in situ disappearance kinetics of DM and NDF for these crabgrass forages. A secondary objective was to compare these kinetic estimates with those of alfalfa (Medicago sativa L.), bermudagrass (Cynodon dactylon [L.] Pers.), and orchardgrass (Dactylis glomerata L.) control hays. All forages were evaluated in situ using five (383 +/- 22.7 kg) ruminally cannulated crossbred (Gelbvieh x Angus x Brangus) steers. Whole-plant crabgrass exhibited more rapid (P < or = 0.002) ruminal disappearance rates of DM (overall range = 0.069 to 0.084 h(-1)) than did bermudagrass (0.054 h(-1)) and orchardgrass (0.060 h(-1)) hays, but disappearance rates were slower (P < 0.001) for crabgrass than for alfalfa hay (0.143 h(-1)). Effective ruminal disappearance of DM was greater (P < 0.001) for crabgrass (overall range = 69.3 to 75.4%) than for all the control hays. Similarly, disappearance rates of NDF for crabgrass (overall range = 0.069 to 0.086 h(-1)) were more rapid (P < 0.001) than observed for bermudagrass and orchardgrass hays; however, NDF in alfalfa disappeared at a faster (P < 0.001) rate (0.107 h(-1)) than crabgrass. These results indicate that crabgrass offers greater effective ruminal degradability of DM and NDF than orchardgrass or alfalfa of moderate quality. More importantly, it potentially offers faster and more extensive ruminal disappearance than perennial warm-season grasses typically found throughout the southeastern United States, and it should likely support improved performance by ruminant livestock in this region.

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).

Common bermudagrass [Cynodon dactylon (L.) Pers.] was harvested from two producer sites (Latta and Stephens) with high soil-test P (286 and 153 ppm, respectively) to assess the effects of N fertilization on P uptake and potential removal in hay or silage. Ammonium nitrate was applied in split applications each year at rates totaling 0, 56, 112, 168, 224, 280, or 336 kg/ha of actual N. At the Stephens site in Yr 1, cumulative DM yield increased linearly (P 0.10) between concentration of P and N fertilization rate (overall mean = 0.40%), but concentrations of P declined in linear (P

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.

Common bermudagrass [Cynodon dactylon (L.) Pers.] growing on a poultry layer manure-amended site (layer manure was last applied in 1999) was fertilized with ammonium nitrate at four rates (0, 56, 112, and 168 kg N ha−1) at approximately 1 month before first and third harvests on 30 May and 18 August 2000 to evaluate forage concentrations of S and Mo, and concentrations and ruminal disappearance of Fe, Zn, and Cu. Five crossbred ruminally cannulated steers (422±21.0 kg BW) were used to evaluate ruminal disappearance of Fe, Zn, and Cu from these forages in situ in a randomized complete block design with a 2×4 (harvest date×N fertilization rate) factorial arrangement of treatments. Forage S concentrations decreased linearly (P=0.02) with increasing N application on both harvest dates, but Fe, Zn, Cu, and Mo concentrations did not differ (P≥0.24) across N fertilization rates. The intercepts for the regressions of S, Zn, Cu, and Mo concentrations on N fertilization rate were higher (P

Minerals are essential nutrients for animals as primordial elements for structural tissues and metabolic reactions. Forages are considered an important source of minerals for ruminants, but forage mineral concentrations may vary across the growing season due to several factors such as forage species and fertilization levels. Common bermudagrass [Cynodon dactylon (L.) Pers.] growing on a poultry layer manure-amended site was fertilized with ammonium nitrate at four rates (0, 56, 112, and 168 kg N/ha) approximately 1 month before the first and third harvests (30 May and 18 August 2000, respectively) to evaluate those effects on forage concentration and ruminal disappearance of Ca, P, Mg, and K. Five crossbred ruminally cannulated steers (422 ± 21.0 kg BW) were used to evaluate these forages in situ in a randomized complete block design with a 2 x 4 (harvest date x N fertilizationrate) factorial arrangement of treatments. Forage P content decreased (P < 0.01) with increasing N fertilization on 18 August, while forage Mg increased (P < 0.01) and forage Ca content tended (P = 0.08) to increase with increasing N fertilization on both harvest dates. Approximately, 992 g/kg of the K disappeared immediately (fraction A) from the bags compared with approximately 821, 718, and 476 g/kg of Mg, P, and Ca, respectively. Fraction A, fraction B (the fraction disappearing at a measurable rate), and effective ruminal disappearance of Ca, P, Mg, and K were affected by linear or quadratic interactions between N fertilization and harvest date. Effective P disappearance increased linearly (P < 0.05) on 30 May and decreased quadratically (P < 0.01).

Spontaneous heating reduces forage quality and nutrient digestibility in stored alfalfa ( Medicago sativa L.) and cool-season grasses. However, research describing the impact of spontaneous heating on disappearance kinetics of warm-season grasses is limited. Five crossbred ruminally cannulated steers were used in a randomized complete block design to determine the impact of spontaneous heating during the curing process on in situ disappearance kinetics of bermudagrass hay. Bermudagrass hays were baled at various moisture levels and bale densities that resulted in spontaneous heating that produced 5, 119, 201, 273, or 401 heating-degree days (HDD; >35 °C) during a 60-day storage period. Hays were evaluated for rumen dry matter (DM), neutral-detergent fiber (NDF), N, and neutral-detergent insoluble nitrogen (NDIN) disappearance kinetics. The immediately soluble DM fraction and effective ruminal DM disappearance generally decreased ( P P K d ) was faster ( P K d for NDF was faster ( P P K d for N was faster ( P P K d for NDIN was faster ( P P

Nutrient composition and in situ dry matter (DM) and neutral detergent fiber (NDF) degradation of bermudagrass [Cynodon dactylon (L) Pers.] may vary with different management and environmental factors. This study evaluated nutritional value and in situ degradation characteristics of DM and NDF for bermudagrass, a perennial, warm-season grass. Bermudagrass growing on a poultry layer—litter—amended site was fertilized with ammonium nitrate at four rates (0, 56, 112, and 168 kg N ha−1) on 28 April and 19 July 2000, then harvested on 10 May and 18 August 2000. Five crossbred ruminally-cannulated steers (422±21.0 kg body weight (BW)) were used in a randomized complete block design with a 2×4 (harvest date×N fertilization rate) factorial arrangement to determine in situ DM and NDF degradation kinetics. Quadratic relationships were detected between N fertilization rates and N concentration in the plant when harvested on 30 May (y=0.0001x2+0.009x+27; P 0.05) across N fertilization rates. The undegraded DM fraction (fraction C) declined (P

Limited information is available describing digestive kinetics of crude protein (CP) in stockpiled bermudagrass ( Cynodon dactylon (L.) Pers.) during late fall and early winter. ‘Greenfield’ bermudagrass was stockpiled at two sites following summer hay or pasture management, and samples were taken at 4-week intervals under caged exclosures (UNGRAZED) and outside exclosures (GRAZED) between 17 October 1997 and 9 January 1998. Forage samples were subsequently incubated in situ in five ruminally cannulated, crossbred steers to determine effects of fall harvest date and previous summer management on in situ degradation kinetics of forage CP. At the hay site, concentrations of total plant CP declined ( P −1 ) and 12 December (119.4 g kg −1 ), but concentrations of CP did not differ ( P >0.05) on the 17 October and 9 January harvest dates. From the pasture site, concentrations of total CP for UNGRAZED forages did not change ( P >0.05) throughout the trial. In situ degradation rates of CP from the hay site were not different ( P >0.05) for UNGRAZED forages on 17 October and 9 January (overall mean=0.056 h −1 ). The ruminal degradation of CP decreased ( P −1 CP between 14 November and 12 December, but did not change during the first and last sampling intervals. At the pasture site, rates of CP degradation increased ( P −1 ) and 9 January (0.080 h −1 ) due to the presence of immature, winter annual weeds. Similarly, the ruminal degradation of CP increased ( P −1 ) and 9 January (624 g kg −1 ) in response to winter annual weed presence. Ruminal availability of CP in stockpiled bermudagrass decreases as the dormant forage ages, but may be adequate to meet the minimum CP requirements of dry, pregnant beef cows.

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.

Wheat (Triticum aestivum L.), oat (Avena sativa L.) and rye (Secale cereale L.) were overseeded into a dormant bermudagrass (Cynodon dactylon (L.) Pers.) sod and harvested on six dates throughout the spring. Plant growth stage was documented for each forage on each harvest date, and harvested forages were subsequently evaluated for forage quality characteristics. Four ruminally cannulated steers were used to evaluate disappearance kinetics of nitrogen (N) by an in situ method. All forages had high concentrations of N (≥31.1 g kg−1 DM) throughout harvest dates in March. By 15 April, rye had reached a substantially more advanced growth stage than either wheat or oat. This trait, coupled with the concurrent taller growth habit, caused concentrations of N in rye to decline (P

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.

Limited information is available that describes the disappearance kinetics of bermudagrass (Cynodon dactylon L. Pers.) during fall and early winter. Five ruminally cannulated, crossbred steers (387 +/- 18.3 kg) were used to determine the effects of calendar date and previous summer management on the in situ degradation kinetics of DM and NDF for forage clipped from stockpiled 'Greenfield' bermudagrass pastures. Forage was stockpiled at two sites following summer hay or pasture management, and samples were taken outside (GRAZED) and under caged exclosures (UNGRAZED) at 4-wk intervals beginning October 17, 1997, and ending January 9, 1998. No effort was made to remove or avoid contaminate species. Concentrations of NDF increased (P0.001) to a maximum for UNGRAZED forages at the hay site between October 17 and December 12, but sampling date had no effect (P = 0.627) on concentrations of NDF at the pasture site. Concentrations of ADF and lignin increased (Por = 0.023) during at least one sampling interval in UNGRAZED forages at both sites. At the hay site, degradation rates of DM decreased (P0.001) by 0.013/h for UNGRAZED forage between October 17 and January 9, whereas the effective ruminal degradability of DM decreased (P0.001) by 33.5% during the same time period. Fractional degradation rates of NDF for UNGRAZED forages at the hay site decreased (P0.001) by 0.014/h between October 17 and November 14 but did not change (Por = 0.077) throughout the remainder of the study. The effective ruminal degradability of NDF decreased (P0.001) by 33.8% between the first and last sampling date. At the pasture site, sampling date did not affect (P = 0.458) rates of DM degradation, but the effective degradability of DM for UNGRAZED forages decreased (P = 0.001) by 19.0% from October 17 to December 12. Rates of NDF degradation for UNGRAZED forages did not differ (Por = 0.113) on the first three sampling dates, but the rate on January 9 was slower than that observed on October 17 (P = 0.025) and November 14 (P = 0.044). The effective degradability of NDF decreased (P0.001) by 19.2% between October 17 and December 12. These data indicate that stockpiled bermudagrass should be used during a limited window during the late fall; after this time, the nutritive value becomes very poor.

Wheat ( Triticum aestivum L.), oat ( Avena sativa L.), and rye ( Secale cereale L.) were overseeded into a dormant bermudagrass ( Cynodon dactylon (L.) Pers.) sod and harvested at 3-wk intervals throughout March, April, May, and early June. Plant growth stage was documented for each forage on each harvest date, and harvested forages were evaluated for forage quality characteristics. Degradation kinetics of DM and NDF for these forages were evaluated by the in situ method. Fractional degradation rates for DM and NDF in all three species were relatively rapid for vegetative forage (≥0.086h –1 ) but declined rapidly by the heading stage of development and stabilized thereafter. Forage quality declined and forages were more resistant to ruminal degradation as plants entered the reproductive stages of growth. Based on these findings, growth stage is an effective predictor of most characteristics of in situ DM and NDF disappearance. The relationships between these degradation parameters and growth stage were typically explained with quadratic or cubic models. Clearly, forage quality characteristics of overseeded rye deteriorated more rapidly with phenological development and growth stage than quality characteristics of overseeded wheat and oat grown in the same environment. For rye, this problem is further complicated by its accelerated phenological development. These factors combine to permit a very narrow harvest window in early spring, relative to the other cereal grains evaluated. Acceptable forage quality may persist for an extended period in wheat and oat; this suggests that producers wishing to utilize these forages may lengthen the harvest window by planting more than one species, either as a mixture or preferably in independent stands.

Background The potential for acid-detergent insoluble ash (ADIA), alkaline-peroxide lignin (APL), and acid-detergent lignin (ADL) to predict fecal output (FO) and dry matter digestibility (DMD) by cattle offered bermudagrass [Cynodon dactylon (L.) Pers.] hays of different qualities was evaluated. Eight ruminally cannulated cows (594 ± 35.5 kg) were allocated randomly to 4 hay diets: low (L), medium low (ML), medium high (MH), and high (H) crude protein (CP) concentration (79, 111, 131, and 164 g CP/kg on a DM basis, respectively). Diets were offered in 3 periods with 2 diet replicates per period and were rotated across cows between periods. Cows were individually fed 20 g DM/kg of body weight in equal feedings at 08:00 and 16:00 h for a 10-d adaptation followed by a 5-d total fecal collection. Actual DM intake (DMI), DMD, and FO were determined based on hay offered, ort, and feces excreted. These components were then analyzed for ADL, APL, and ADIA concentration to determine marker recovery and marker-based estimates of FO and DMD. Results Forage DMI was affected by diet (P = 0.02), and DMI from MH and H was greater (P