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PubMed1995

Effect of forage digestibility and type of concentrate on nutrient utilization by lactating dairy cattle.

Six lactating dairy cows were used in a three period, part balanced changeover design experiment to investigate the effects of forage digestibility and concentrate composition on the efficiency of nutrient utilization in lactating dairy cows. Six treatments comprising three forage regimens and two concentrate types (starch v. fibre) were examined in a 3 x 2 factorial design. The three forage regimens were high digestibility grass silage offered ad lib. (HA) or restricted to 6.5 kg dry matter/d (HR) and a low digestibility grass silage offered ad lib. (LA). Within each forage regimen animals were offered 10 kg/d of supplements containing either high-starch or high-fibre concentrations. Experimental periods lasted 28 d with a 10 d recording period, during which animal performance, ration digestibility and nitrogen and energy utilization were measured. Respiratory exchange measurements were made over a 72 h period using indirect open-circuit calorimetry. Throughout the experiment, there were no significant forage x concentrate interactions in any of the intake, production or nutrient utilization results. Milk yield was significantly influenced by forage regimen (24.1, 21.7 and 21.9 kg/d for HA, HR and LA respectively) and concentrate type (21.6 and 23.5 kg/d for high-starch and high-fibre respectively). Concentrate type also significantly influenced milk protein concentration (32.8 and 30.9 g/kg for high-starch and high-fibre respectively). Forage regimen significantly influenced the efficiency of utilization of metabolizable energy (ME) for milk production (k1) with values of 0.62, 0.64 and 0.59 for HA, HR and LA respectively. Concentrate type had no significant effect on ME intake, heat production or k1, although animals receiving the high-fibre concentrates synthesized proportionately 0.11 more milk energy per unit of available energy (ME intake--heat production) than those receiving the high-starch concentrates. Interpolation of the values obtained with the two high digestibility forage regimens indicated that at similar ME intakes there was a trend towards a higher k1 with the diet based on high digestibility silage, and this was in line with the higher metabolizability of the overall diet with this silage.

Animal Feed↗
PubMed2005

Foraging behaviour of Armillaria rhizomorph systems.

The foraging behaviour of Armillaria rhizomorph systems is poorly understood owing to their cryptic position within the soil. We investigated foraging in a homogeneous environment (i.e. agar), finding that rhizomorph systems of the more parasitic species, A. mellea, A. ostoyae, and A. tabescens, lacked melanin and the approximately cylindrical cord-like form observed in the field. In contrast, rhizomorph systems of the more saprotrophic species, A. calvescens, A. gallica, and A. sinapina, developed radially resembling those in the field. For the three saprotrophic Armillaria species, the number of rhizomorph tips, total rhizomorph length and total rhizomorph surface area were significantly positively correlated with increasing rhizomorph system diameter and elapsed time in two developmental tests. However, the fractal dimension (D), used as a measure of foraging intensity, was temporally invariable, suggesting that one component of foraging behaviour is innate. In a heterogeneous environment (i.e. sand) and in the absence of a potential nutrient source, we observed that rhizomorph systems of A. gallica most often developed asymmetrically. While rhizomorph foraging was unresponsive to the lateral placement of an uncolonised stem segment, we were able to demonstrate directional growth toward an uncolonised Quercus velutina stem segment placed above or below the colonised source stem segment. When neighboring rhizomorph systems were conspecific genets of A. gallica, we observed that the growth of one rhizomorph system was directed toward zones unoccupied by its neighbour. However, the foraging intensity of the neighbouring genets, as measured by fractal dimension (D), was unaffected by the proximity of a neighbour. When neighbouring rhizomorph systems represented different species (A. gallica and A. mellea), A. gallica rhizomorph systems produced more total length and more foraging tips but concentrated their rhizomorph production away from the neighbouring A. mellea genet. In contrast, A. mellea rhizomorph systems produced significantly more foraging tips per unit length, both overall and in the zone of confrontation with the neighbouring A. gallica genet. Our observations are consistent with field observations of territoriality among Armillaria genets, and provide evidence that rhizomorph systems of more parasitic Armillaria spp. are able to compete effectively with the larger rhizomorph systems of more saprotrophic Armillaria species.

Agar↗
PubMed2006

Influence of cultivation site on sesquiterpene lactone composition of forage chicory (Cichorium intybus L.).

The forage potential of chicory (Cichorium intybus L.) has not been realized in southern West Virginia (WV) because ruminants are reluctant to consume the herbage. Chicory contains bitter sesquiterpene lactones that can adversely impact palatability. This study was undertaken to determine whether sesquiterpene lactone concentrations in chicory grown in southern WV differ from those in chicory grown in central Pennsylvania (PA) where chicory is grazed readily. Herbage was collected in 1997 and 1998 from cultivars Grasslands Puna (Puna), INIA le Lacerta (Lacerta), and Forage Feast established at research sites near State College, PA, and Beckley, WV. The total concentration of sesquiterpene lactones in WV-grown cultivars was 0.58% (dry matter basis) in Puna, 0.59% in Lacerta, and 0.79% in Forage Feast in 1997 and ranged from 1.03 (Lacerta) to 1.52% (Forage Feast) in 1998. In PA-grown cultivars, sesquiterpene lactones represented 0.16 (Puna), 0.18 (Lacerta), and 0.27% (Forage Feast) of the forage dry matter in 1997 and ranged from 0.32 (Lacerta) to 0.55% (Forage Feast) in 1998. Concentrations of lactucin, lactucopicrin, and total sesquiterpene lactones in Forage Feast exceeded those in the other cultivars grown at the same site. The lowest concentrations of lactucopicrin and total sesquiterpene lactones observed among WV-grown cultivars were higher (2-fold or more) than the highest concentrations present in cultivars grown the same year in PA. Mineral analyses of soils from the two cultivation sites indicate that P availability may influence sesquiterpene lactone composition of chicory herbage. Results provide a foundation for future studies of environmental effects on sesquiterpene lactone composition and palatability of chicory herbage.

Animal Feed↗
PubMed2001

To walk or to fly? How birds choose among foraging modes.

We test the predictive value of the main energetic currencies used in foraging theory using starlings that choose between two foraging modes (walking versus flying). Walking is low-cost, low-yield, whereas flying is the opposite. We fixed experimentally, at 11 different values, the amount of flight required to get one food reward, and for each flight cost value, we titrated the amount of walking until the birds showed indifference between foraging modes. We then compared the indifference points to those predicted by gross rate of gain over time, net rate of gain over time, and the ratio of gain to expenditure (efficiency). The results for the choice between modes show strong qualitative and quantitative support for net rate of gain over time over the alternatives. However, the birds foraged for only a fraction of the available time, indicating that the choice between foraging and resting could not be explained by any of these currencies. We suggest that this discrepancy could be accounted for functionally because nonenergetic factors such as predation risk may differ between resting and foraging in any mode but may not differ much between foraging modes, hence releasing the choice between foraging modes from the influence of such factors. Alternatively, the discrepancy may be attributable to the use of predictable (rather than stochastic) ratios of effort per prey in our experiment, and it may thus be better understood with mechanistic rather than functional arguments.

Animals↗
PubMed2002

Recent advances in our understanding of risk-sensitive foraging preferences.

Many experiments have shown that foraging animals are sensitive to the riskiness, or variance, associated with alternative food sources. For example, when offered a choice of a constant feeding option that always offers three seeds, and a risky option that offers either no seeds or six seeds with equal probability, most animals tested will be either risk-averse or risk-prone, preferring either the fixed or variable option respectively. Whether animals are risk-averse or risk-prone appears to depend on a range of factors, including the energetic status of the forager, the type of variance associated with the feeding options and even the number of feeding options between which the animal is choosing. These behavioural phenomena have attracted much theoretical interest, and a range of different explanations have been suggested, some based on a consideration ofthe psychological mechanisms involved in decision making, and others on a consideration of the Darwinian fitness consequences of risk-averse or risk-prone behaviour for the forager. A brief review of the recent literature on risk-sensitive foraging will be presented, focusing on results from the two experimental systems with which I have been involved: wild rufous hummingbirds (Selasphorus rufus) foraging on artificial flowers; European starlings (Sturnus vulgaris) foraging in operant boxes in the laboratory. It will be argued that to understand the foraging decisions of animals account needs to be taken of both the psychological mechanisms underlying decision-making and the fitness consequences of different decisions for the forager.

Animals↗
PubMed2003

Integrating the roles of information and competitive ability on the spatial distribution of social foragers.

Understanding and predicting the spatial distribution of social foragers among patchily distributed resources is a problem that has been addressed with numerous approaches over the 30 yr since the ideal free distribution (IFD) was first introduced. The two main approaches involve perceptual constraints and unequal competitors. Here we present a model of social foragers choosing among resource patches. Each forager makes a probabilistic choice on the basis of the information acquired through past foraging experiences. Food acquisition is determined by the forager's competitive ability. This model predicts that perceptual constraints have a greater influence on the spatial distribution of foragers than unequal competitive abilities but that competitive ability plays an important role in determining an individual's information state and behavior. Better competitors have access to more information; consequently, we find that competitive abilities and perceptual constraints are integrated through the social environment occupied by individual foragers. Relative competitive abilities influence the forager's information state, and the ability to use information determines the resulting spatial distribution.

Animals↗
PubMed2003

Optimization, conflict, and nonoverlapping foraging ranges in ants.

An organism's foraging range depends on the behavior of neighbors, the dynamics of resources, and the availability of information. We use a well-studied population of the red harvester ant Pogonomyrmex barbatus to develop and independently parameterize models that include these three factors. The models solve for an allocation of foraging ants in the area around the nest in response to other colonies. We compare formulations that optimize at the colony or individual level and those that do or do not include costs of conflict. Model predictions were compared with data collected on ant time budgets and ant density. The strategy that optimizes at the colony level but neglects costs of conflict predicts unrealistic levels of overlap. In contrast, the strategy that optimizes at the individual level predicts realistic foraging ranges with or without inclusion of conflict costs. Both the individual model and the colony model that includes conflict costs show good quantitative agreement with data. Thus, an optimal foraging response to a combination of exploitation and interference competition can largely explain how individual foraging behavior creates the foraging range of a colony. Deviations between model predictions and data indicate that colonies might allocate a larger than optimal number of foragers to areas near boundaries between foraging ranges.

Animals↗
PubMed2004

Brood pheromone regulates foraging activity of honey bees (Hymenoptera: Apidae).

Brood pheromone modulated the foraging behavior of commercial honey bee, Apis mellifera L., colonies pollinating a 10-ha market garden of cucumber, Cucurbita pepo L., and zucchini, Cucumis saticus L., in Texas in late autumn. Six colonies were randomly selected to receive 2000 larval equivalents of brood pheromone and six received a blank control. The ratio of pollen to nonpollen foragers entering colonies was significantly greater in pheromone-treated colonies 1 h after treatment. Pheromone-treated foragers returned with pollen load weights that were significantly heavier than controls. Pollen returned by pheromone-treated foragers was 43% more likely to originate from the target crop. Number of pollen grains washed from the bodies of nonpollen foragers from pheromone-treated colonies was significantly greater than controls and the pollen was 54% more likely to originate from the target crop. Increasing the foraging stimulus environment with brood pheromone increased colony-level foraging and individual forager efforts. Brood pheromone is a promising technology for increasing the pollination activity and efficiency of commercial honey bee colonies.

Animals↗
PubMed2006

Green turtle (Chelonia mydas) foraging and nesting aggregations in the Caribbean and Atlantic: impact of currents and behavior on dispersal.

Although significant amounts of research have been dedicated to increasing the knowledge of the life history of green turtles (Chelonia mydas), large gaps exist in our understanding of juvenile migratory behavior. These gaps can be filled by genetic studies of foraging ground aggregations. Using mitochondrial DNA markers and Bayesian analyses, samples (n = 106) from a foraging aggregation in North Carolina indicated that animals from the east coast of the United States (54%) and Mexico (27%) dominate the composition with the remainder coming from other Caribbean and Atlantic nesting aggregations. These findings prompted a reanalysis of 4 regional foraging aggregations using Bayesian mixed stock analysis, analysis of molecular variance, and diversity measures. Significant regional population structure between northern and southern foraging aggregations in the Caribbean was detected (phiST = 0.27, P = 0.000) in addition to significant nesting aggregation structure (phiST = 0.87, P = 0.000). Haplotype diversity levels were highest at foraging aggregations located within the confluence of major current systems. These findings indicate that both currents and behavior have strong influences on the composition of foraging aggregations. In addition, our results provide evidence of juvenile homing to regional foraging grounds and highlight the difficulties of separating historical and current effects on recruitment patterns at foraging locations.

Animal Population Groups↗
PubMed2005

Effects of blue lupin (Lupinus angustifolius) in organic layer diets and supplementation with foraging material on egg production and some egg quality parameters.

Six groups of organically fed hens were studied for egg production, feed parameters, and egg quality from 20 to 31 wk of age. Treatments were 3 diets (0, 15, and 25% blue lupin) with or without supplements of foraging material (whole carrots and corn silage). Increased lupin content increased nonstarch polysaccharides content and reduced methionine content below the hens' requirement. Egg production at 31 wk was lower with the 25% lupin diet without (69%) and with foraging material (76%) compared with the other diets (approximately 90%). Egg weight was highest with the 0% lupin diet (64 g), and 15% lupin diet (60 g), whereas the 25% lupin diet without and with foraging material resulted in egg weights of 58 and 56 g, respectively. Feed intakes were approximately 113 g of diet/ hen per d and 113 g of supplement/hen per d in 0 and 15% lupin treatments, respectively. Feeding the 25% lupin diet significantly reduced diet intake to approximately 91 g, and increased supplement intake to 118 g for the treatment with foraging material. Eggs from treatments with foraging material had significantly higher sulfur-like aftertaste in sensory evaluation. Yolk color became significantly lighter and more yellow with lupin content, but darker and less greenish with foraging material. Increased lupin levels decreased albumen DM, whereas foraging material had no effect. Inclusion of 25% lupin in layer diets is only recommended when supplying some methionine source, as egg production and quality parameters are dramatically impaired. However, supplement of foraging material significantly improves egg production.

Animal Feed↗
PubMed2005

The three-dimensional flight of red-footed boobies: adaptations to foraging in a tropical environment?

In seabirds a broad variety of morphologies, flight styles and feeding methods exist as an adaptation to optimal foraging in contrasted marine environments for a wide variety of prey types. Because of the low productivity of tropical waters it is expected that specific flight and foraging techniques have been selected there, but very few data are available. By using five different types of high-precision miniaturized logger (global positioning systems, accelerometers, time depth recorders, activity recorders, altimeters) we studied the way a seabird is foraging over tropical waters. Red-footed boobies are foraging in the day, never foraging at night, probably as a result of predation risks. They make extensive use of wind conditions, flying preferentially with crosswinds at median speed of 38 km h(-1), reaching highest speeds with tail winds. They spent 66% of the foraging trip in flight, using a flap-glide flight, and gliding 68% of the flight. Travelling at low costs was regularly interrupted by extremely active foraging periods where birds are very frequently touching water for landing, plunge diving or surface diving (30 landings h(-1)). Dives were shallow (maximum 2.4 m) but frequent (4.5 dives h(-1)), most being plunge dives. While chasing for very mobile prey like flying fishes, boobies have adopted a very active and specific hunting behaviour, but the use of wind allows them to reduce travelling cost by their extensive use of gliding. During the foraging and travelling phases birds climb regularly to altitudes of 20-50 m to spot prey or congeners. During the final phase of the flight, they climb to high altitudes, up to 500 m, probably to avoid attacks by frigatebirds along the coasts. This study demonstrates the use by boobies of a series of very specific flight and activity patterns that have probably been selected as adaptations to the conditions of tropical waters.

Adaptation, Physiological↗
PubMed2006

Deep-diving foraging behaviour of sperm whales (Physeter macrocephalus).

1. Digital tags were used to describe diving and vocal behaviour of sperm whales during 198 complete and partial foraging dives made by 37 individual sperm whales in the Atlantic Ocean, the Gulf of Mexico and the Ligurian Sea. 2. The maximum depth of dive averaged by individual differed across the three regions and was 985 m (SD = 124.3), 644 m (123.4) and 827 m (60.3), respectively. An average dive cycle consisted of a 45 min (6.3) dive with a 9 min (3.0) surface interval, with no significant differences among regions. On average, whales spent greater than 72% of their time in foraging dive cycles. 3. Whales produced regular clicks for 81% (4.1) of a dive and 64% (14.6) of the descent phase. The occurrence of buzz vocalizations (also called 'creaks') as an indicator of the foraging phase of a dive showed no difference in mean prey capture attempts per dive between regions [18 buzzes/dive (7.6)]. Sperm whales descended a mean of 392 m (144) from the start of regular clicking to the first buzz, which supports the hypothesis that regular clicks function as a long-range biosonar. 4. There were no significant differences in the duration of the foraging phase [28 min (6.0)] or percentage of the dive duration in the foraging phase [62% (7.3)] between the three regions, with an overall average proportion of time spent actively encountering prey during dive cycles of 0.53 (0.05). Whales maintained their time in the foraging phase by decreasing transit time for deeper foraging dives. 5. Similarity in foraging behaviour in the three regions and high diving efficiencies suggest that the success of sperm whales as mesopelagic predators is due in part to long-range echolocation of deep prey patches, efficient locomotion and a large aerobic capacity during diving.

Acoustics↗
PubMed2000

Social wasp (Hymenoptera: Vespidae) foraging behavior.

Social wasps (Hymenoptera: Vespidae) forage for water, pulp, carbohydrates, and animal protein. When hunting, social wasps are opportunistic generalists and use a variety of mechanisms to locate and choose prey. Individual foragers are influenced by past foraging experience and by the presence of other foragers on resources. A forager's ability to learn odors and landmarks, which direct its return to foraging sites, and to associate cues such as odor or leaf damage with resource availability provide the behavioral foundation for facultative specialization by individual foragers. Social wasps, by virtue of their behavior and numbers, have a large impact on other organisms by consuming them directly. Indirect effects such as disruption of prey and resource depletion may also be important. Community-level impacts are particularly apparent when wasps feed upon clumped prey vulnerable to depredation by returning foragers, or when species with large, long-lived colonies are introduced into island communities. A clearer understanding of these relationships may provide insight into impacts of generalist predators on the evolution of their prey.

Animals↗
PubMed1989

The influence of time of day on the foraging behavior of the honeybee, Apis mellifera.

The honeybee time sense, or Zeitgedächtnis, is highly adaptive, allowing bees to synchronize their foraging behavior with the peak time of daily floral nectar rhythms. Each foraging group within the honeybee colony shows a high degree of fidelity to one species of flower. Across the day, the temporal accuracy of foraging visits to experimental feeding times varies considerably, being nearly exact for morning-trained foraging groups but becoming less so for foraging groups trained later in the day. The evidence gained in this study suggests that the diel change in accuracy exhibited by foraging groups, which persists after the removal of many potential environmental time cues, is an endogenously driven behavior pattern. Furthermore, it appears that individual bees are continuously and accurately aware of the time of day, but are programmed to forage with greater anticipation to late-day food sources. Therefore, two separate processes contributing to the honeybee time sense are implicated. The first varies with time of day and determines the amount of anticipatory activity directed toward the food source. The second process is invariant across the day and is involved with the individual forager's continuous, accurate awareness of time.

Animals↗
PubMed2005

Nutritional status influences socially regulated foraging ontogeny in honey bees.

In many social insects, including honey bees, worker energy reserve levels are correlated with task performance in the colony. Honey bee nest workers have abundant stored lipid and protein while foragers are depleted of these reserves; this depletion precedes the shift from nest work to foraging. The first objective of this study was to test the hypothesis that lipid depletion has a causal effect on the age at onset of foraging in honey bees (Apis mellifera L.). We found that bees treated with a fatty acid synthesis inhibitor (TOFA) were more likely to forage precociously. The second objective of this study was to determine whether there is a relationship between social interactions, nutritional state and behavioral maturation. Since older bees are known to inhibit the development of young bees into foragers, we asked whether this effect is mediated nutritionally via the passage of food from old to young bees. We found that bees reared in social isolation have low lipid stores, but social inhibition occurs in colonies in the field, whether young bees are starved or fed. These results indicate that although social interactions affect the nutritional status of young bees, social and nutritional factors act independently to influence age at onset of foraging. Our findings suggest that mechanisms linking internal nutritional physiology to foraging in solitary insects have been co-opted to regulate altruistic foraging in a social context.

Age Factors↗
PubMed1991

Nutrient utilization by sheep fed forage grown on soil treated with fluidized-bed combustion residue.

A mineral balance trial was conducted with 18 wether lambs fed sun-cured hay harvested from pastures located on a reclaimed strip-mined site. The following soil applications were made during each of 3 yr: 1) none, 2) dolomitic limestone and 3) fluidized-bed combustion residue (FBCR). Because FBCR had half the buffering capacity of limestone, it was applied at twice the rate of limestone. Apparent digestibility of hemicellulose was higher (P less than .05) for limestone-amended forage than for FBCR-amended forage (70.2 vs 67.0%), and apparent digestibility of cellulose was higher (P less than .05) for amended forages (66.7%) than for the control (63.9%). Apparent absorption and retention of N were similar among treatments, when expressed as a percentage of intake. Lambs fed control forage were in negative Ca balance, lower (P less than .01) than with amended forages. Apparent absorption and retention of Mg and Fe (g/d basis) were higher (P less than .05) for lambs on the limestone treatment than for lambs on the FBCR treatment. Apparent absorption of S was higher (P less than .01) for lambs on the FBCR treatment than for those on the limestone treatment. These differences were related to differences in mineral concentrations of the forages. Serum P was lower (P less than .05) for lambs fed FBCR-treated forage than for lambs fed limestone-treated forage (10.1 vs 12.9 mg/dl). Soil amendment with FBCR did not have deleterious effects on digestibility or mineral metabolism; in fact, it may have enhanced utilization of Ca and S and improved digestibility of some fiber components by lambs.

Animal Feed↗
PubMed1995

Plant compositional constituents affecting between-plant and animal species prediction of forage intake.

The purpose of the study was to identify plant compositional constituents that influence forage intake. Emphasis was put on the ratio in vitro digestibility of organic matter (IVDOM):NDF because preliminary work with cattle and a limited number of forages showed the ratio to account for more variation in intake than either IVDOM or NDF alone. The compositional constituents were tested in intake prediction models using local and published data (n = 302) on grass pastures, silages, hays, straws, legumes, grass-legume mixtures, and shrubs ingested by both browsing and grass-eating ruminants (goats, red deer, impala, blesbok, sheep, cattle, and blue wildebeest). In the local experiments, esophageally fistulated and fecal bag-harnessed animals were used to collect representative grazed forage samples from pastures and to determine OM excreted, respectively. Forage intake was calculated as OM excreted divided by (1-IVDOM). Intake of silages, hays, and straws was measured indoors in digestibility trials. Intakes among species were compared after scaling for size by BW raised to the power of .9. Major contributors to the variation in forage intake were ash, hemicellulose, IVDOM:NDF, ADL, and the interaction between DM content and, respectively, ash, N, and ADL. High tannin/phenol concentrations proved limiting to intake. The ratio of IVDOM:NDF accounted for 67% of the variation in forage intake if data for which the other constituents had an effect were omitted, and the equation, OMI, g.kg BW-.9.d-1 = 70-97e-.975(IVDOM:NDF), predicted intake across all forages and ruminant species with a Sy.x of 5.3 g.kg BW-.9.d-1 (CV = 15%). The ratio of IVDOM:NDF should be valuable as a relatively inexpensive and rapid method to screen forages and cultivars.

Animals↗
PubMed2001

Effects of calendar date and summer management on the in situ dry matter and fiber degradation of stockpiled forage from bermudagrass pastures.

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 (P < 0.001) 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 (P < or = 0.023) during at least one sampling interval in UNGRAZED forages at both sites. At the hay site, degradation rates of DM decreased (P < 0.001) by 0.013/h for UNGRAZED forage between October 17 and January 9, whereas the effective ruminal degradability of DM decreased (P < 0.001) by 33.5% during the same time period. Fractional degradation rates of NDF for UNGRAZED forages at the hay site decreased (P < 0.001) by 0.014/h between October 17 and November 14 but did not change (P > or = 0.077) throughout the remainder of the study. The effective ruminal degradability of NDF decreased (P < 0.001) 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 (P > or = 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 (P < 0.001) 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.

Animal Feed↗