Heterogeneous distribution of ungulates about the landscape can be a particularly vexing problem for resource managers. Although livestock preferences for leaves over stems among plants and patches of herbage are well documented, effects of senescent for- age (herbage supporting both green and cured materials) on cattle distribution and nutrition at pasture scales have not been investigated. Our primary objective was to determine the proportions of time cattle spent foraging within senescent and con- ditioned sectors (areas supporting only current season’s herbage) of pastures. Other endeavors included the following: comparing velocities of foraging cattle in conditioned and senescent sectors, determining diet quality of cattle confined to conditioned and senescent treatments, and quantifying levels of forage utilization by cattle in conditioned and senescent treatments. Global positioning system collars were used to track cattle movement and activity in treated crested wheatgrass (Agropyron desertorum [Fisher ex Link] Schultes) pastures. Over a 7-day trial, cattle were found in senescent and conditioned areas 41% and 59% of the time, respectively. When cattle were grazing, 32% of observations were in senescent sectors and 68% were in conditioned areas. With a decline in standing crop in the conditioned treatment, cattle switched to senescent herbage (73% of observations) on day 7. Standing crop was reduced by 13% to 40% in conditioned sectors and increased by 10% in senescent areas. Despite dispa- rities in the crude protein of standing crops in senescent (x= 6.5%) and conditioned (x= 11.3%) treatments, cattle confined to treatment harvested diets of similar quality (x= 13.6% CP) at turn-out. Cattle walked farther when making transitions between treatments, and walked farther each day as the trial progressed. A preference of foraging cattle for portions of pastures grazed (con- ditioned areas) during the previous growing season suggests that utilization patterns established by livestock are self-sustaining.

Global positioning systems (GPSs) enable continuous and automatic tracking of an animal's position. The value of such spatial-temporal information can be improved if the corresponding activity of the animal is known. We evaluated the potential of Lotek GPS collars to predict activity of beef cattle on extensive rangeland in 2 contrasting foraging environments. Collars were configured to record animal location at intervals of 20 minutes (United States) or 5 minutes (Israel), together with counts from 2 motion sensors. Synchronized field observations of collared cows were conducted in 1999 (United States) and in 2002 and 2003 (Israel). Grazing, traveling (without grazing), and resting activities were recorded as minutes out of 20 for each category (United States), or as a single category (Israel). For the US data, stepwise regression models of grazing, traveling, and resting time accounted for 74%-84% of the variation, on the basis of the motion sensor counts for the left-right axis and the distances between GPS fixes. Regression tree analysis of grazing time yielded a simple model (4 splits) that accounted for 85% of the variation. For the Israeli data, the misclassification rates obtained by discriminant analysis and classification tree analysis of animal activity were 14% and 12%, respectively. In both analyses, almost all grazing observations were correctly classified, but other activities were sometimes misclassified as grazing. Distance alone is a poor indicator of animal activity, but grazing, traveling, and resting activities of free-ranging cattle can be inferred with reasonable accuracy from data provided by Lotek GPS collars.

Research on Anderson and Scherzinger's hypothesis that spring cattle grazing can positively affect subsequent nutritional characteristics of grasses have generated mixed results. Our objectives were: 1) to evaluate fall/winter nutritional indices of bluebunch wheatgrass (Agropyron spicatum [Pursh] Scribn. Smith), Idaho fescue (Festuca idahoensis Elmer), and bottlebrush squirreltail (Sitanion hystrix (Nutt.) Smith) in ungrazed, lightly grazed (33% utilization), or heavily grazed (69% utilization) pastures stocked with cattle at the boot stage of growth; and 2) to quantify opportunity costs of applying those treatments on fall standing crop. Compared with ungrazed stands, light and heavy spring grazing decreased September standing crop by 32 and 67%, respectively. September/December crude protein (CP) among heavily grazed grasses (x̄ = 6.9%) exceeded ungrazed controls (x̄ = 3.9%) for 11 of 12 comparisons. Crude protein of lightly grazed grasses (x̄ = 5.2%) was higher than ungrazed controls for 6 of 12 comparisons. Herbage was more nutritious during the drier of the 2 years sampled. Among grazed treatments, fall/winter CP measures were highest for bottlebrush squirreltail (x̄ = 7.4%), intermediate for Idaho fescue (5.9%), and lowest for bluebunch wheatgrass (0=4.9%). In fall/winter, herbage was most digestible in heavily grazed paddocks (x̄ = 59%), intermediate in lightly grazed paddocks (x̄ = 53%), and least digestible in ungrazed areas (x̄ = 49%). Light and heavy spring cattle grazing can augment fall/winter forage quality of bluebunch wheatgrass, Idaho fescue, and bottlebrush squirreltail. Spring grazing reduces subsequent standing crop, but remaining forage will be nutritionally superior to herbage in ungrazed stands.

Due to its palatability and forage quality, antelope bitterbrush (Purshia tridentata Pursh DC) is a desirable shrub across western US rangelands. Because little information is available regarding grazing management of young bitterbrush, a study was undertaken to explore stocking pressure thresholds and quantify effects of light and heavy spring cattle grazing on shrub growth. Rates of browsing and trampling and forage availability were monitored over 3 years in southeast Oregon. Across years, 29% of bitterbrush endured trampling in light-grazing treatments, and 55% experienced trampling under heavy grazing. Linear models relating time and cattle density successfully explained (r(2) = 0.84-0.86) probabilities of bitterbrush being trampled. Forage utilization averaged 32% and 59% in lightly and heavily grazed units, and 14 and 62% of bitterbrush were browsed in lightly and heavily-grazed pastures, respectively. Cattle began browsing when herbaceous standing crop declined to 100-150 kg ha(-1). Browsing in heavily-grazed pastures reduced diameters of bitterbrush by 4.5 to 9.5 cm in 1998 and 1999, but shrub height was unaffected. Lightly-grazed stands exhibited a 50% greater increase in bitterbrush diameter, 30% greater height increment, and 8% longer twigs than shrubs in ungrazed pastures. At the end of the 1997 and 1998 growing seasons, bitterbrush in heavily-grazed pastures were 11 cm greater in diameter than ungrazed controls and equal to shrubs in lightly-grazed pastures. To stimulate bitterbrush growth, young stands can be lightly-grazed (30 to 40% utilization of herbaceous forage) by cattle when bitterbrush is flowering and accompanying grasses are in vegetative to late-boot stages of phenology.

Livestock and wildlife managers must be aware of the nutritional dynamics of forages to sustain satisfactory growth and reproduction of their animals and assure fair value for pasture. Despite a history of livestock grazing in the northern Great Basin, annual and seasonal mineral concentrations of many of the region's prominent grasses have not been measured. We addressed this problem with monthly sampling (April-November) of 7 cool-season grasses at 6 sites during 1992, a drier than average year (86% of mean precipitation), and 1993 when precipitation was 167% of average (255 mm). Grasses included: Poa sandbergii Vasey, Bromus tectorum L., Sitanion hystrix (Nutt.) Smith, Agropyron spicatum (Pursh) Scribn. & Smith, Festuca idahoensis Elmer, Stipa thurberiana Piper, and Elymus cinereus Scribn. & Merr. Phosphorus, K, Ca, Mg, Mn, Fe, Cu, Zn, and Na were assayed, and initial statistical analysis was a split-split-plot with main effects of species, years, and months and all possible interactions. For a preponderance of the minerals, (Zn and Na excluded) the 3-way year x month x species interactions were significant (P < 0.05) indicating that main effects did not function independently. Generally, mineral concentrations averaged about 41% higher among the grasses for the drier of the 2 years (1992). Copper, Zn, and Na concentrations were below required levels for beef cattle (9.9, 28.8, and 672 mg kg-1, respectively) among all the grasses for all sampling periods. Seasonally deficient minerals included Ca, Mg, P, K, and Mn. Calcium and Mn were largely deficient (< 3.2 and 1.15 g kg-1, respectively) for beef cattle early in the growing season with levels rising as grasses matured. Seasonal patterns of Mg were variable among the grasses, increasing in some as the season progressed, remaining stable among others, and declining with maturity in yet others. Phosphorus and K levels were typically adequate (> 1.94 and 5.76 g kg-1, respectively) for beef cattle early in the growing season and declined to deficient levels by July and August. Iron was of no concern, because concentrations were more than adequate for cattle (> 48 mg kg-1) among all the grasses for all seasons. While a mixed stand of forages can extend the period of adequate mineral nutrition for cattle in some instances, we suggest that a supplement be available season-long on northern Great Basin rangelands and that the formulation include at least Ca, Mg, P, K, Cu, Zn, Mn, and Na in available forms and proper ratios.

SUMMARY Livestock grazing of a northeastern Oregon riparian pasture was monitored using high- frequency GPS tracking of cattle and high-resolution aerial photography. Tracking collars recorded positions, velocity, date, and time at 1-sec intervals. Areas where animals rested and moved were identified and residence times calculated for various locations and plant communities in the pasture. Tracking collars performed well and data from 74 days of continuous 24-hour observation were compiled, more than 10 days of observation on 7 cows. Activity diagrams and daily travel distances were determined for each animal, as was preference for ecological sites. Maps that showed travel routes and stream crossing areas were also produced. Managerial implications of the collected information are discussed. found: "Traditional agriculture is probably the largest contributor to the decline of riparian areas… The primary effects of livestock grazing include the removal and trampling of vegetation, compaction of underlying soils, and dispersal of exotic plant species and pathogens. Grazing can also alter both hydrologic and fire disturbance regimes, accelerate erosion, and reduce plant or animal reproductive success and /or establishment of plants. Long-term cumulative effects of domestic livestock grazing involve changes in the structure, composition, and productivity of plants and animals at community, ecosystem, and landscape scales." Modern, rational grazing management systems of riparian areas have been developed and adopted by private ranches and federal and state agencies. These systems were created by university, USDA/Agricultural Research Service, Natural Resource Conservation Service, and Federal agency personnel and are designed to reduce impacts of livestock on critical environmental attributes of riparian systems, such as vegetation along the green line, streamside shrubs, and bank overhang that can negatively impact native plants, fish, and wildlife. Managerial systems typically adjust the timing and/or intensity of grazing such that cattle impacts are controlled while economic benefits to producers are maintained. Knowledge of animal distribution within the context of site preference and site accessibility is central to the development of these grazing management plans and most were developed by experienced managers. Today Geographic Information Systems (GIS) and Global Positioning Systems (GPS)

Several of the problems associated with grazing animals in extensive settings are related to their uneven patterns of use across the landscape. After fencing, water and salt are two of the most frequently used tools for affecting cattle distribution in extensive settings. Cattle are attracted to water in arid regions, but mixed results have been obtained with salt and mineral supplements. The goal of this study was to evaluate the efficacies of salt and water manipulations for affecting cattle distribution in large (>825ha) pastures. This was accomplished by fitting cattle with global positioning system (GPS) collars and monitoring their travels and activities in a three pasture, Latin-square design where water and salt shared a common location and water or salt were moved individually to distant areas. Mean distance of cattle from water (&xmacr;=1.16km) was unaffected by treatments (P=0.79) suggesting that cattle followed movements of water tanks. Distance traveled daily (&xmacr;=5.78km), time devoted to grazing (11.0h per day), time devoted to resting (10.1h per day), and the area (&xmacr;=325ha) of minimum convex polygons were also unaffected by treatment implying that cattle did not compensate for separated water and salting areas with increased travels or disruptions of habitual grazing and resting activities. Centers of activity for cattle shifted further (P=0.02) when water (&xmacr;=1.49km) was moved than when salt (&xmacr;=1.00km) was relocated. Mean distance of cattle from salt increased from 1.03km, when salt and water were together, to 1.73km (P=0.08) when salt and water were separated. This implied that cattle made less effort to remain near salt. Also, when water and salt were separated, cattle were found within 250m of water 354 times and close to salt only 38 times. Movement of drinking water to distant points in pastures was the most effective tool for altering cattle distribution. When cattle and salt were introduced to a new portion of a pasture, cattle used the new area for about 2 days, and then began drifting back toward previously used portions of the pasture. Manipulations of salting stations will not significantly rectify serious livestock distribution problems in extensive arid-land pastures.

Land, livestock, and wildlife managers need to understand the nutritional dynamics of forages to sustain adequate growth and reproduction of their animals and/or assure equitable payment for forages. Despite a long history of livestock grazing in the northern Great Basin, seasonal and annual nutritional dynamics of many of the region's prominent grasses have not been described. We addressed this issue via monthly sampling of 7 cool-season grasses at 6 sites during 1992, a drier than average year having 86% of mean precipitation, and 1993, when above average precipitation (167% of average) occurred. With high yields predicted in 1993 (1,257 kg ha(-1)), the period of adequate forage quality [crude protein (CP) greater than or equal to 7.5%] was 83 days. In addition grasses did not respond to 97 mm of July-August rain with renewed growth. During 1992, a growing season beginning with less than average moisture, grasses responded to midsummer (49 mm) and fall (69 mm) rains by maintaining greater than 7.5% CP for 185 days. A diversity of grasses expanded the period of adequate forage quality especially during the lower than average moisture year. Giant wildrye (Elymus cinereus Scribn. Merr.), a deeply rooted grass, supported high quality forage until mid August, but did not respond to late-season moisture. In contrast, shallow rooted grasses like bottlebrush squirreltail (Sitanion hystrix (Nutt.) Smith), Sandberg's bluegrass (Poa sandbergii Vasey), and the winter-annual cheatgrass (Bromus tectorum L.) responded to summer or fall moisture with herbage ranging from 10 to 16% CP, thereby supplying high quality late-season forage. With most precipitation occurring in the northern Great Basin during colder months, livestock or habitat managers can, with a fair degree of certainty, predict yields from their pastures before turnout. With abundant moisture, managers will see the rapid deterioration of forage quality that occurs when grasses advance through their reproductive stages of phenology and generate a wealth of reproductive stems. The quandary arrives, however, when moisture accumulations are less than optimum. Fewer reproductive tillers develop, and our results show that timely precipitation may elevate desirable nutrient characteristics and expand the duration of adequate livestock/wildlife nutrition in the region. More long-term research is needed to decipher the mechanisms governing growth and development of rangeland grasses and to assess risks of various stocking alternatives when managers face uncertain yield and forage quality issues.

Livestock trails frequently evolve in pastures when plant growth or establishment cannot keep pace with vegetation disturbance. In some instances, man-made trails are established in rangeland settings to encourage uniform use of forages or facilitate livestock passage through dense vegetation or across rugged terrain. A long-term assumption has been that livestock establish pathways of least resistance between frequented areas of their pastures, but this hypothesis has never been tested. We mapped cattle trails in three 800+ ha pastures with global positioning units. A geographic information system (GIS) helped quantify characteristics of trails and the landscape and was used to plot least-effort pathways between water sources and distant points on selected trails in the pastures. Characteristics of the cattle trails and least-effort pathways were compared to test the hypothesis that cattle develop least-effort routes of travel in rugged terrain. The mean slope of the three pastures was 13.5%, and the average slope of the topography traversed by the cattle trails was 8%. The slope of the trails was reduced to 5.2% by selection of cross-slope routes. When we compared the characteristics of 10 selected cattle trails and least-effort pathways generated by our GIS, the cattle trails were 11% shorter (P=0.046) than the least-effort pathways, and the topography traversed by cattle had a gradient about 1% less than the least-effort pathways (P=0.02). The slope of the selected trails (5.5%) and pathways (5.6%) were similar (P=0.74), however. Analyses of values extracted from cost surfaces indicated that, on the average, 183 units of effort were needed to traverse the trails and 170 units of effort expended to traverse the least-effort pathways (P=0.07). These data support the hypothesis that cattle establish least-effort routes between distant points in rugged terrain and suggest that GIS software may be useful in designing systems of livestock trails in extensive settings.

Because of its high palatability and sustained levels of forage quality, antelope bitterbrush (Purshia tridentata Pursh DC) is one of the most desired shrubs on western U.S. rangelands. Bitterbrush has decreased in abundance in many areas, and efforts to foster its restoration have met with limited success. Because little information is available regarding the grazing management of newly established stands of bitterbrush, this study was undertaken to: 1) determine the effects of early and late-season cattle grazing on bitterbrush, 2) determine when cattle were most likely to forage on these shrubs, and 3) relate use of shrubs to the quantity, quality, and phenology of accompanying herbaceous forages. Ungrazed (control), early-grazed, and dormant-grazed paddocks supporting 3(+) year old bitterbrush (randomized complete block design, N = 3) were monitored for 3 years to accomplish this task. When grasses were green and growing, cattle grazed about 6% of the shrubs per day. When grasses and forbs were dormant, about 13% of the shrubs were grazed each day. Rates of use of shrubs were not significantly (P > 0.05) correlated with amounts of accompanying herbage available (r(2) = 0.40), levels of forage utilization (r(2) = 0.00), stocking pressure (r2 = 0.00), crude protein (r(2) = 0.02) or neutral detergent fiber content (r(2) = 0.59) of accompanying forages, or digestibility of the forages as measured by in-vitro organic matter disappearance (IVOMD) (r(2) = 0.62). In stepwise regression analyses Julian date alone accounted for 92 % of the variation in rates of use of shrubs and the addition of IVOMD accounted for 98% of the variation. This suggested that bitterbrush was grazed more heavily as the growing season advanced and forage quality of the grasses declined. Shrub height, diameter, and volume were reduced by early grazing in 1 of 3 years when turn out was delayed until grasses were entering anthesis. Cattle grazing when grasses were dormant caused reductions in height, diameter, and volume of the shrubs in all 3 years. Rates of shrub mortality were unaffected by treatment. Bitterbrush in all treatments experienced significant reductions in height, diameter, and volume from wildlife use during the winters of 1993 and 1993 but not 1995. When trials were terminated, shrubs in early-prated paddocks exceeded (P < 0.10) their counterparts in the dormant grazed paddocks in height, diameter, and volume. Shrubs in early-treatments also exceeded ungrazed controls in diameter and volume. Early grazing of pastures either reduced competition or directly stimulated twig growth of the bitterbrush, If managers wish to conserve critical browse for wintering wildlife or enhance development of young bitterbrush, we suggest that pastures be grazed before the most prominent grasses reach anthesis. After grasses have cured, rates of use on bitterbrush by cattle may be 2 to 3 times higher than when accompanying forages were succulent and growing.

Cattle are often required to adapt to new forages when they are moved to new pasture. The objectives of this research were: (1) to determine how rapidly naive cattle express clearly defined preferences when they encounter a new array of forages, and (2) to compare their evolving forage preferences and grazing behavior with those of experienced cattle. Three naive and three experienced yearling-steers were grazed in experimental paddocks supporting equal numbers of eight different caespitose grasses, and the number of visits to plants and number of bites harvested were monitored. Experienced steers immediately began grazing preferred forages, and throughout the trials, 90% of their visits were made to the two preferred grasses, giant wildrye (Elymus cinereus Scribn. and Merr.), and `Nordan' crested wheatgrass (Agropyron desertorum (Fischer ex Link)Schultes). After the naive steers had sampled only nine individual plants, they selected the same two grasses as the experienced steers at significantly (P=0.05) higher frequencies than expected by chance. Diets of the naive steers, however, remained significantly different (P=0.001) from the experienced steers for the duration of the trials, so we could not determine the amount of exposure or time required for the selective patterns of the two treatments to approach parity. Across the 4-day trial, 97% of total bites by the experienced animals were from the two preferred grasses, while the naive animals took only 88% of their total bites from the same forages (P=0.001). Naive steers were also more likely to abandon a plant after harvesting a single-bite of forage (37%) than the experienced steers (19.5%). In approximately the same amount of time, naive steers harvested 21% fewer total bites than experienced animals, suggesting that naive animals were less efficient grazers. If naive cattle are introduced to an array of new forages, they may begin expressing dietary preferences paralleling those of indigenous animals within less than 5 min. Researchers, however, should not assume that naive cattle will provide an accurate depiction of the dietary composition of native stock, because naive cattle may sample a broader array of forages than their experienced counterparts and harvest fewer bites than experienced cattle from the preferred forages. Further research over more than 4 consecutive days will be required to determine the time necessary for `naive' animals to be considered `experienced'. These data also suggest that active cattle management may be focused on relatively few species even when pastures contain a heterogeneous mix of forages.

Although Thurber needlegrass (Stipa thurberiana Piper) is an important component of Palouse, sagebrush:steppe, and pine:forest rangelands, little is known of its qualitative and quantitative responses to defoliation. At 14-day intervals one of 7 cohorts of Thurber needlegrass plants was defoliated to a 2.5-cm stubble to describe initial growth rates, determine defoliation effects on subsequent regrowth accumulations, relate regrowth potential to available soil moisture, and determine the nutritional value of initial growth and regrowth for livestock. The study was conducted in 1985 and 1986 with a different group of plants used each year. Although crop-year precipitation for the 1985-86 treatment years was 77 and 111%, respectively, of the long term mean (25.2 cm), growth rates of tussocks were similar between years (P > 0.05). Seasonal yield of regrowth varied between years, however, and was well correlated (r2 = 0.76 to 0.80 P < 0.05) with soil moisture content when treatments were applied. Among 7 defoliation dates (24 April-17 July) only the first 5 yielded regrowth in 1985, and all produced regrowth in 1986. Among treatments regrowth averaged 22% of total herbage yield in 1985 and 50% of total yield in 1986. In both years total herbage accumulations were most suppressed (47-63% reduction) by defoliation during the early-boot stage of phenology. In 1985 when conditions were drier, any defoliation before mid-June depressed (P < 0.05) total herbage yield. Crude protein (CP) of needlegrass herbage was high (19-22%) when growth began in April but declined (P < 0.05) to marginal levels for cattle (6.7-7.7%) by mid-July. Regrowth harvested on 31 July ranged from 7 to 9% CP for the earliest (24 April) treatments and as high as 17% for the latest (17 July). Although Thurber needlegrass can produce highly nutritious regrowth for late-season use, managers face diminishing levels of regrowth as the initial cropping date is delayed later into the growing season. Managers contemplating 2-crop grazing regimes for Thurber needlegrass should base scheduling on plant phenology, soil moisture considerations and historic use rather than specific calendar dates. Further work is needed, however, to definitively determine Thurber needlegrass responses to long-term manipulative grazing regimes.

The objective of this research was to determine, on a seasonal basis, the relative preferences of cattle for 7 native grasses and crested wheatgrass (Agropyron desertorum (Fischer ex Link)Schultes), a long-used introduction in the Pacific Northwest, Methods involved observing forage selection processes of 3 steers in paddocks, where plants existed in equal densities and in rangeland pastures with variable forage composition. Design of paddock and pasture studies was a randomized-complete-block with 3 replications, 3 stages of phenology (vegetative, anthesis, and quiescent), and 8-11 forages. Dietary proportions as indexed by bite-counts changed (P < 0.01) with phenology and varied among species. Diets were more similar (P < 0.05) than forage composition between the 2 study areas (paddocks and native pastures), and became less similar (p < 0.05) as phenology of the grasses advanced from vegetative growth through anthesis and quiescence. Steers were selective grazers during vegetative and anthesis stages of phenology, and despite variations in herbage availability, 'Nordan' crested wheatgrass was the most prominent dietary component in paddocks and pastures. Variation in proportions of grasses in the diet was associated (P < 0.05) with measures of available forage in the paddocks (r = 0.46-0.89, (x) over bar = 0.72) but poorly associated with herbage composition in pastures (r = 0.41-0.02, (x) over bar = 0.12). Inconsistencies in rankings of relative preference indices and dietary proportions of grasses suggested that measures of herbage availability may confound the predictive utility of relative preference indites. More grasses were acceptable to cattle at quiescence, with crested wheatgrass ranging from 8-26% of the diet. We suggest that with proper management, interseedings of crested wheatgrass on native range may be used to lessen grazing demands previously borne by native perennials early in the grazing season.

An early focus on ungulate foraging behavior occurred in the 1940's as scientists began quantifying the activities of livestock and wildlife to address production goals. Interest resurfaced in the 1970's and continued as investigators pondered behavior related hypotheses at evolutionary, ecosystem, and plant/animal interface levels. Presently, many grazing land environmental concerns are related to the selective foraging habits of ungulates and their poor distribution about the landscape. These two facets of ungulate behavior serve as the impetus for many of today's research efforts. and scientists in the field need to develop a theoretical framework to address these problems. The theories of optimum foraging and adaptive rumen function were offered to explain evolutionary patterns of forego selection among herbivores, but they lack the specificity needed by range and pasture managers at relevant space and time scales. While post-ingestive feedback mechanisms cause aversions to toxic plants, and some species of herbivores have developed means of neutralizing harmful compounds, the mechanisms stimulating the development of forage preferences in the absence of aversive compounds are not clearly understood. Ungulates also exhibit selective patterns of spatial use about the landscape. In some environments where necessary resources (water, shade, forage. minerals, escape topography or cover) are scarcer areas of activity will be focused about these limiting elements. Many of the herding ungulates, however, repeatedly regraze certain areas and avoid other equally suitable portions of the landscape. Research suggests these habits elevate the animal's nutritional status by curtailing advances in plant phenology and removing the hindrances of cured forage from the grazed parches. Such a scenario increases landscape diversity and may enhance species richness and accelerate nutrient cycling in the grazed areas by maintaining vegetation in an earlier stage of succession. Recent investigations suggest that ungulates ran retain and use spatial memory to expedite foraging, and can associate shapes and colors with the presence or absence of food. These skills have been clearly demonstrated in small, well controlled environments, but patterns of behavior and distribution in extensive landscape settings are poorly understood. The recent advances in geographic information systems and global positioning systems will assist us greatly in our analyses of ungulate behavior at landscape levels of resolution. Pasture and landscape managers are beginning to recognize many of the innate habits and preferences of livestock though, and are exploiting these behaviors to affect plant succession, control weeds, and manipulate forage quality or structure of the plant community. There is much left to learn, but as we make inroads in these endeavors, the value of grazing animals can only increase.

Portable computers presently allow documentation of real-time grazing behavior under field conditions. Researchers are still challenged, however, with the task of selecting proper and easily recorded variables to test their hypotheses. The objective of this research was to examine relationships among variables describing grazing behavior and forage utilization by goats to identify the most easily monitored activity capable of accurately ranking their relative preferences among forages. Relationships were investigated in grassy paddocks and on native shrub/steppe rangeland. Variables recorded for each forage included: total visits, total bites, bites per visit, total grazing time, time per visit, and bite rate in both environments, and number of plants grazed, number of plants regrazed, number of regrazing events, percent utilization, grazed plant utilization, and number of plants utilized in the grassy paddocks. In grassy paddocks, with eight different forages available, total visits, total bites, total time, number of plants grazed, number of plants regrazed, and number of regrazing events were highly correlated (r ≥ 0.94 and P < 0.01) during both the boot and dormant stages of phonology. Rank correlation coefficients (rs) among forages with these variables averaged 0.96. Any of these six variables would probably give satisfactory ranking of relative preferences if the animal in question was confined to or elected to forage from a single life form (grass, forb, shrub, or tree). Utilization data were significantly (P < 0.01) but poorly correlated (mean r = 0.74) with total bites, total visits and total time. Correlations among grazing behavior variables were all statistically significant (P < 0.01) but much weaker in shrub/steppe vegetation where a variety of life forms were available (mean r = 0.45), Only total time versus total bites and bites per visit versus time per visit exhibited correlations of 0.94 or greater (P < 0.01). The poorer correlations obtained on rangelands were attributed to a wide array of foraging techniques used by the goats to graze the various grasses, forbs, shrubs, and trees. Total time was the only variable consistently correlated with total bites in both the grassy paddock and shrub/steppe pastures (mean r = 0.94). Monitoring of grazing time devoted to each forage could be more easily accomplished than the more attention demanding process of tallying individual bites. We suggest that adequate rankings of relative forage preference of goats could be obtained by a single observer recording grazing time expended on each forage.

We compared the forage preferences of steers grazing among 8 varieties of grasses at 2 stages of phenology on the Northern Great Basin Experimental Range near Burns, Ore. Varieties included: ‘Nordan (Agropyron desertorum (Fischer ex Link)Schultes) and ‘CD-II’ (A. desertorum X A. cristatum (L.) Gaertner) crested wheatgrass; ‘Magnar’ and ‘Trailhead’ Basin wildryes (Leymus cinereus (Scribner & Merrill) A. Liive); ‘Golda? bluebunch wheatgrass (Pseudoroegneria spicata (Pursh)A. Liive); ‘Bozoisky-Select’ Russian wildrye (Psathyrostachys junceus (Fischer) Nevski); ‘Bannock’ thickspike wheatgrass (Elymus lanceolatus ssp. lanceolatus (Scribner & J.G. Smith) Gould), and ‘Secar’ Snake River wheatgrass (proposed nomenclature Elymus lanceolatus ssp. wawawaiensis (Scribner & J.G. Smith) Gould). Three esophageal-Bstulated steers grazed each paddock, with 3 paddocks grazed at the boot stage of development, and 3 paddocks grazed after grasses entered quiescence. In boot-stage trials, steers were very selective and collectively harvested 53% of total bites from the preferred CD-II and Nordan. These crested wheatgrasses also ranked higher (P 0.95, P < 0.01) with total bites harvested from varieties and are probably adequate for ranking relative preferences of steers. By selectively grazing at both stages of phenology, cattle diets were hlgher in CP, P, and ADL than the standing crop. During boot-stage trials, diets were also higher in Ca and Mg than forage analyses would suggest Except for phosphorus, the nutritive content of all varieties was satisfactory for lactating beef cattle at both stages

The botanical composition of the diet of eight Spanish goats was studied on the Northern Great Basin Experimental Range during two stages of plant phenology (active growth in early July and cured forage in mid-August) to assess their potential for control of sagebrush (Artemisia tridentata subspp. wyomingensis Nutt.) and western juniper (Juniperus occidentalis Hook.) and the nutritional value of their diets on sagebrush steppe rangelands. Diets were quantified by documenting the number of visits to each species, the number of bites harvested and time expended grazing each forage over four consecutive days in each period, Forage chemical characteristics evaluated included: CP, NDF, ADF, ADL and IVDMD. Diet composition and forage quality indices varied significantly (P<0.05) with changes in plant phenology. Vegetation cover averaged 52% in the pasture and consisted of 36% grasses, 8% forbs, 7% shrubs and 0.6% trees. Available herbage (excluding woody plants) was 534 kg ha(-1) during active growth trials and 572 kg ha(-1) when forages had cured. When Forages were green goats acquired 28% of their total bites from grasses, 71% from forbs, 0.3% from shrubs and 0.9% from juniper trees. After forages had cured values were 35% from grasses, 56% from forbs, 0.1% from shrubs and 8.8% from juniper. The browsing of juniper (both foliage and bark), alter herbaceous forages had cured, was the only substantive use of woody plants. Sagebrush was only lightly used (0.2% of total bites) when herbaceous forages were actively growing. Available herbage was of relatively high quality during both trials. When forages were actively growing, CP of grasses ranged between 8.9-5.6%, forbs from 17.7-8.5%, sagebrush scored at 8.5%, juniper foliage at 8.1% and juniper bark at 3.2%. After herbaceous forages had cured, grass CPs ranged between 6.2 and 3.1%; forbs from 10.4 to 4.4%; shrubs were not sampled; and juniper foliage averaged 7.6%. Given the low levels of browsing exhibited by goats on sagebrush and juniper we see little opportunity for control of these woody plants when pastures provide a diverse (n = 25 species) array of readily available (534-572 kg ha(-1)) and nutritious forages and pastures are lightly stocked (0.63 goats ha(-1) month(-1)). We do need, however, to explore further their potential for control of these species under several other regimes. These include: extended trials on more deteriorated rangelands; trials during seasons or conditions where forage is limited and the animal's selective opportunity is restricted; and trials in high quality environments on newly established sagebrush and juniper seedlings.

Mature Angora goats were pastured in plots supporting eight selections of grasses used for rangeland reclamation in the northern Great Basin. The objectives were to establish the relative preferences of goats for these forages at two stages of phenology (late-boot and dormant) and relate selective preferences to forage production and quality attributes. Numbers of each selection visited, total bites harvested, and percent plant weight utilized characterized diets of goats. Forage attributes included herbage production, CP, and IVOMD. Crested wheatgrass selections (cultivars 'Nordan' and 'Hycrest II') were consistently ranked as preferred forages at both stages of phenology, with the two receiving 80+% of the grazing activity. Cultivars 'Magnar' and 'Trailhead' basin wildrye, 'Goldar' bluebunch wheatgrass, and 'Bozoisky' Russian wildrye were ranked as indifferently foraged upon, and a numbered selection (No. 9021076) of thick-spiked wheatgrass and the closely related cultivar 'Secar' Snake River wheatgrass ranked as avoided, Variation in herbage production among selections was significantly and positively correlated with visits to selections and total bites but not well enough to be an accurate predictor of selectivity. Indices of forage quality (CP and IVOMD) were not significantly correlated with selectivity. Adequate livestock performance can probably be attained on the preferred and indifferently ranked forages through mid-summer without supplementation. The two thick-spiked wheatgrasses, No, 9021076 and 'Secar' Snake River wheatgrass, are not recommended as forages for Angora goats.

Knowledge of an animal's tendencies, including their directional biases, can aid in design of handling facilities and enhance our understanding of livestock and livestock:environment interactions. Recent work suggests that goats consistently prefer to turn left in mazes. The objective of this research was to determine if free-ranging angora goats (Capra hircus) exhibit left- or right-hand tendencies when grazing in paddocks supporting randomized arrays of forages. This was accomplished during two 3-day sampling periods by compiling successive feeding station locations of individual goats as they grazed and evaluating frequencies of left, right, forward, and reverse movements. Analyses revealed no significant (P ⩾ 0.01) evidence of a left- or right-hand bias by either individuals or the sampled population of goats. Changes in direction, however, were not always independent or random events. In two instances, extended series of left- or right-turns occurred suggesting these data can at times be clustered (P ⩽ 0.01). Conversely, in four instances, animals systematically (P ⩽ 0.01) shifted between left- and right-hand turns as they grazed. While the potential for non-random turning behavior suggested that extended observations be used to quantify directional tendencies of free-ranging goats, there were no indications of left- or right-handed inclinations by the animals in unconfined conditions.

Residual stems or cured straw in caespitose grasses are frequently a detriment to utilization of herbage by both wild and domestic herbivores. Cattle alter their grazing methods and remove less forage from plants contaminated with old-growth material. The objective of this research was to establish the degree and persistence of cattle responses to low densities of cured seed stalks in tussocks of crested wheatgrass (Agropyron desertorum (Fisher ex Link) Schultes), as pasture resources were progressively depleted. This was researched by augmenting individual plants with densities of 0, 1, 2 or 3 cured seed stalks dm−2 basal area, and measuring the frequency and degree of utilization by cattle throughout a 6-day grazing trial. Cattle were less likely to graze and removed less material from plants as the density of cured stems increased. Frequency means indicated cattle responded to treatments differing by two or more stems. Utilization data suggested cattle were aware of just one cured stem in a tussock. Plants augmented with one, two and three cured stems were, respectively, 8%, 20% and 32% less likely to be grazed than control tussocks with no stems, and these same treatments had, respectively, 35%, 39% and 60% less material removed by cattle than controls. Livestock owners or land managers are encouraged to keep pastures free of cured straw or litter to facilitate more uniform and efficient use of forage by livestock or wildlife.