• A modified faecal harness for grazing goats on Mediterranean shrublands

      Yiakoulaki, M. D.; Nastis, A. S. (Society for Range Management, 1998-09-01)
      A modified faecal harness for goats was specially designed for grazing conditions in dense mediterranean shrublands and subsequently tested successfully for total faecal collection. The details of design and collection are presented.
    • Alpaca liveweight variations and fiber production in Mediterranean range of Chile

      Castellaro G., G.; García-Huidobro P de A, J.; Salinas, P. (Society for Range Management, 1998-09-01)
      A study of liveweight changes of alpaca adult males, females, and their progeny, was conducted through 3 seasons under continuous grazing on natural grasslands on the Mediterranean range of the Chilean Central Zone. Liveweight changes were positive and highest in spring (100 to 200 g day-1), moderate during winter (50 to 100 g day-1), and negative only at the end of summer and in fall (-110 to -150 g day-1). Weight gains of new born alpacas were greatest (110 to 150 g day-1) in the first 90 days after birth and then decreased slightly, reaching values of 75 g day-1 at 8.5 months old. Weight gains stabilized at 10 to 20 g day-1 at 3-years of age. The average annual fibre production was 1.57 and 236 kg in females and males, respectively; staple length varied between 8 and 10 cm.
    • Detecting channel morphology change in California's hardwood rangeland spring ecosystems

      Allen-Diaz, B.; Jackson, R. D.; Fehmi, J. S. (Society for Range Management, 1998-09-01)
      Permanent channel cross-sectional transects perpendicular to flow were used to estimate changes in spring and resultant creek channel morphology. Three cattle grazing treatments (none, light, and moderate) were applied to 2-5 ha pastures containing a perennial spring and resultant creek cohort for 5 years. Grazing effects on the total change in channel morphology were not detected, nor did our method detect channel morphology change over the 5 year study period. Ungrazed springs and creeks were observed to change more than grazed springs and creeks although these differences were not statistically significant. Observed, but not significant, change over time appears related to rainfall patterns. Permanent channel cross-sections, one of the currently recommended methods for monitoring livestock grazing impacts on stream channels, may not be adequate for detecting channel changes in low-flow spring/creek systems.
    • Forage selection by cattle on fescue prairie in summer or winter

      Willms, W. D.; Rode, L. M. (Society for Range Management, 1998-09-01)
      The rough fescue grasslands are important for livestock grazing as well as other values such as wildlife habitat, recreational opportunities, and watershed properties. The impact of livestock on these grasslands must be better understood in order to manage grazing for optimal use of the resource. A study was conducted from 1992 to 1994 on the rough fescue grassland near Stavely, Alberta, to determine forage selection by cattle in the winter and summer and the effect of canola supplementation on forage selection. Twelve 1.7-ha paddocks were stocked with 2 cows (Hereford) at 3.2 animal-units-months ha-1 in winter; canola supplements (0.0, 0.4, 0.8, and 1.2 kg animal-1 day-1) were applied in a randomized complete block design. Three additional 1.7-ha paddocks were similarly stocked but grazed in the summer with out canola supplements. Forage availability, utilization, and relative preference were estimated for 4 major plant species. In both winter and summer, rough fescue (Festuca campestris Rydb.) was utilized most (P < 0.05) and Idaho fescue (Festuca idahoensis Elmer) and smooth aster (Aster laevis L.) were utilized the least. Of total forage utilized, rough fescue and Parry oat grass (Danthonia parryi Scribn.) contributed about 90 and 9%, respectively, in winter and about 62 and 32%, respectively, in summer. In summer, Parry oat grass was utilized in proportion to its availability. Rough fescue was the preferred species in both winter and summer. Percent forage utilization in winter was not affected by supplementation with canola. The high preference for rough fescue appeared to be determined by the accessibility of the large tufted plants to cattle. This was particularly evident in winter when access to plants was impaired by snow cover. Successful winter grazing on these grasslands is enhanced with a large proportion of rough fescue plants in the stand.
    • Heated substrate and smoke: influence on seed emergence and plant growth

      Blank, R. R.; Young, J. A. (Society for Range Management, 1998-09-01)
      Combustion products of burning vegetation can increase seed germination of many species of fire-prone plant communities. We tested the influence of heating sagebrush (Artemisia tridentata Nutt.) subcanopy soil, aqueous extracts of artificially burned soil, and sagebrush smoke on the emergence of several range plant species of the sagebrush-steppe. In addition, test seeds were exposed to sagebrush smoke and aqueous slurries of artificially burned sagebrush subcanopy soil to determine their effect on plant growth. As compared to the control, substrates previously heated from 250 to 750 degrees C significantly (P less than or equal to 0.05) increased the emergence of Thurber's needlegrass [Achnatherum thurberianum (Piper) Barkworth] and needle-and-thread [Hesperostipa comata (Trin. & Rupr.) Barkworth]. Sagebrush smoke and aqueous slurries of artificially burned soil significantly increased the emergence of Sierra Nevada needlegrass [Achnatherum occidentalis (Thurber) Barkworth], Indian ricegrass [Achnatherum hymenoides (Roemer & Schultes) Barkworth], and antelope bitterbrush [Purshia tridentata (Pursh) DC.]. Rates of new leaf production and leaf elongation following treatment of seeds with the smoke of burning sagebrush were significantly greater for cheatgrass (Bromus tectorum L.), basin wildrye [Leymus cinereus (Sribner & Merr.) A. Löve], Idaho fescue (Festuca idahoensis Elmer ), Sierra Nevada needlegrass, and needle-and-thread as compared to the control. After 83 days of growth, smoke-treated seeds of basin wildrye and needle-and-thread produced significantly greater plant mass than their controls. Smoke treatment of certain seeds before sowing is potentially useful for range plant seedings.
    • Influence of abiotic and biotic factors in measuring and modeling soil erosion on rangelands: State of knowledge

      Weltz, M. A.; Kidwell, M. R.; Fox, H. D. (Society for Range Management, 1998-09-01)
      The first standardized soil erosion prediction equation used on rangelands was the Universal Soil Loss Eguation (USLE). The Revised Universal Soil Loss Equation (RUSLE) was developed to address deficiencies in the USLE by accounting for temporal changes in soil erodibility and plant factors which were not originally considered. Improvements were also made to the rainfall, length, slope, and management practice factors of the original USLE model. The Water Erosion Prediction Project (WEPP) model was developed to estimate soil erosion from single events, long-term soil loss from hillslopes, and sediment yield from small watersheds. Temporal changes in biomass, soil erodibility, and land management practices, and to a limited extent, spatial distribution of soil, vegetation, and land use are addressed in the WEPP model. To apply new process-based erosion prediction technology, basic research must be conducted to better model the interactions and feedback mechanisms of plant communities and landscape ecology. Thresholds at which accelerated soil erosion results in unstable plant communities must be identified. Research is needed to determine the confidence limits for erosion predictions generated by simulation models so that the probability of meeting specified soil loss values (kg ha-1 yr-1) for given management systems can be calculated at specific significance levels. As the technology for modeling soil erosion on rangelands has improved, limitations with the techniques of parameter estimation have been encountered. Improvements in model parameterization techniques and national databases that incorporate vegetation and soil variability are required before existing erosion prediction models can be implemented.
    • Mineral-salt supplement does not attenuate tall larkspur (Delphinium barbeyi) toxicosis in cattle

      Pfister, J. A.; Cheney, C. D.; Gardner, D. R.; Manners, G. D. (Society for Range Management, 1998-09-01)
      Severe livestock losses caused by tall larkspur (Delphinium spp.) consumption have caused many producers to try various preventative measures, including the use of mineral-salt supplementation. The objective of tbis study was to determine if additions or deletions of a mineral-salt supplement (Binn's #1 Alleviator) would alter the response (i.e., rate of nose pressing) of cattle to tall larkspur exposure. The dose response of 5 Jersey steers was examined by systematically adding 0.25 mg of mineral-salt/kg body weight, and comparing responses in the same steers without salt supplements. Steers were then run under a variable ratio (VR) reinforcement schedule and periodically dosed with tall larkspur at a level causing a significant decrease in responding without provoking overt signs of intoxication. Response rate with and without mineral-salt supplement was the major dependent variable; 3 to 5 "on-off" cycles were conducted for each subject. Steers reduced (P < 0.05) their rate of grain intake by 34% during operant sessions when larkspur was dosed compared to the previous non-dosed 3-day baseline. Rate of nose pressing was reduced (P < 0.01) on tall larkspur dose days by 28% vs. the 3-day non-dosed baseline. This reduction was indicative of the effects of the effects of subclinical larkspur intoxication on steers. On days when larkspur was dosed and animals were intoxicated, the addition of mineral did not alter (P > 0.1) grain intake (1.64 +/- 0.17 kg/session) compared to days when no mineral was given (1.76 +/- 0.13 kg/session). On larkspur dose days (i.e. when animals were intoxicated), the average response rates were 82.9 +/- 3.7 and 85.8 +/- 4.0 responses/min (P > 0.1) when off and on mineral, respectively. We concluded that mineral/salt supplementation had no effect on the response of steers to doses of tall larkspur that produced subclinical intoxication.
    • Pine needle consumption by cattle during winter in South Dakota

      Pfister, J. A.; Panter, K. E.; Gardner, D. R. (Society for Range Management, 1998-09-01)
      Pregnant cattle that consume ponderosa pine (Pinus ponderosa (Lawson) needles often abort. The objectives of these studies were to: 1) determine needle consumption by grazing cattle; 2) relate consumption in pen-fed and grazing cattle to weather variables; and 3) determine if needle temperature influenced consumption in pen-fed cattle. Trial 1 was conducted from 3 Dec. 1991 to 12 Feb. 1992 near Custer, S. Dak. Eight mature cows grazed a 9-ha pasture. Needle consumption was measured using bite counts H. and fecal analysis. The winter was mild, and cattle consumed few needles (< 2% of bites). Trial 2 was conducted in the same location from 5 January to 2 March 1993, using 6 pregnant cows kept in pens and 5 open cows grazing the pasture. The pen-fed cows were offered 1 kg of fresh pine needles daily; methods for grazing cattle were the same as in the previous trial. Further, the pen-fed cows were offered warm or cold green needles in 2 acceptability trials. Grazing cattle consumed an average of 20% of bites as pine needles. As snow depth increased, pine needle consumption increased, particularly from short (< 2 m tall) tree (P < 0.01). The percent of bites of green needles was related (r2 = 0.69) to minimum temperature and snow depth, with greater consumption at colder temperatures and at deeper snow depths. As snow depth increased, cattle reduced daily grazing time (P < 0.01); at colder temperatures, cattle also reduced grazing time (P < 0.05). Pen-fed cows ate 483 g pine needles/day (fresh weight), with no abortions occurring. Cattle preferred cold needles to warm needles (P < 0.05) in January, despite tree size; whereas, the opposite result was noted in February. We conclude that snow depth, reduced amounts of grazable forage, and cold ambient temperatures are crucial factors in consumption of ponderosa pine needles by grazing cattle.
    • Seasonal grazing impact on cryptogamic crusts in a cold desert ecosystem

      Memmott, K. L.; Anderson, V. J.; Monsen, S. B. (Society for Range Management, 1998-09-01)
      Since settlement, cattle grazing has been a major cause of soil disturbance in cold desert ecosystems. The objective of this study was to determine the impact of cattle grazing in different seasons on cryptogamic soil crusts. This study was conducted adjacent to the Brigham Young University Skaggs Research Ranch, near Malta, Ida. Five areas of a crested wheatgrass pasture each interplanted with shrubs were evaluated. Each of the 5 areas was subdivided into 4 paddocks; a control paddock remained ungrazed, while the other 3 paddocks were grazed in either spring, summer, or winter. Each of the 1.2-ha grazed paddocks was grazed annually in the same season for 2 consecutive years by 10 cows for 4 consecutive days. Percent of the soil surface covered by litter, vascular plant bases, and cryptogams was measured using a 10-pin, point sampling frame. Mosses were the main component of the cryptogamic soil crusts under all grazing treatments. Winter grazing had no effect on the moss component of the crusts while spring and summer grazing reduced mosses. While winter grazing had significantly less impact on the lichen component of crusts relative to spring and summer grazing, there was a 50% reduction relative to the control plots. Total cryptogamic cover in the control paddocks averaged 27.6%; winter grazed paddocks 27.4%; summer grazed paddocks 14.4%; and spring grazed paddocks 10.6%. Controlled winter grazing has minimal impact on the total cryptogamic plant cover that protect soil surfaces on cold desert range ecosystems.
    • Seasonal preferences of steers for prominent northern Great Basin grasses

      Cruz, R.; Ganskopp, D. (Society for Range Management, 1998-09-01)
      The objective of this research was to determine, on a seasonal basis, the relative preferences of cattle for 7 native grasses and d 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, average = 0.72) but poorly associated with herbage composition in pastures (r = 0.41-0.02, average = 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 indices. 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.
    • Seedling growth of intermountain perennial and weedy annual grasses

      Arredondo, J. T.; Jones, T. A.; Johnson, D. A. (Society for Range Management, 1998-09-01)
      Squirreltail [Elymus elymoides (Raf.) Swezey] is a native cool-season grass that has been observed to invade rangelands dominated by the weedy annual grasses, cheatgrass (Bromus tectorum L.) and medusahead wildrye [Taeniatherum caput-medusae (L.) (Nevski]. Our objective was to determine if growth characteristics could account for this squirreltail trait. We used growth analysis to examine differences in seedling growth and tissue allocation of 5 squirreltail entries, 2 long-lived perennial grasses ('Goldar' bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) A. Löve] and 'Hycrest' crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult. X A. cristatum (L.) Gaertn.]), cheatgrass, and medusahead wildrye. We monitored the 9 entries in a greenhouse for mean relative growth rate, net assimilation rate, leaf area ratio, specific leaf area, leaf weight ratio, root relative growth rate, specific root length, root-to-shoot dry-mass ratio, and root length-to-leaf area ratio beginning 10 days after sowing at 9 destructive harvests at 3-day intervals. Cheatgrass had high relative growth rate for both shoot and root. Only medusahead wildrye equalled the shoot relative growth rate of cheatgrass, and only Hycrest equalled its root relative growth rate. Cheatgrass seedlings were larger than squirreltail seedlings by 2 to 3 weeks after emergence. Few differences were detected among perennials and medusahead wildrye. Cheatgrass displayed the highest leaf area ratio and specific leaf area of the 9 entries but was similar to medusahead wildrye and Red Deer River squirreltail for specific root length. Growth characteristics cannot account for squirreltail's observed ability to invade annual grass stands. However, the combination of high specific leaf area and specific root length in squirreltail germplasm, as found in cheatgrass, may enhance squirreltail survival under competition with annual grasses, especially medusahead wildrye.
    • Simulated cattle fever tick infestations in rotational grazing systems

      Teel, P. D.; Grant, W. E.; Marin, S. L.; Stuth, J. W. (Society for Range Management, 1998-09-01)
      Prior simulation analysis of cattle fever tick population dynamics has indicated that fixed rotation, short duration grazing (SDG) systems could mediate the spread of ticks among pastures if rest periods were greater than 100 to 150 days. A question arose whether variable rotations with rest periods approaching 35-70 days could mediate the spread of ticks within these rapid, rotational grazing systems. An 8-pasture:1-herd extensive (26-34 days:182-238 days graze:rest) and intensive (5-10 days: 35-70 days graze:rest) short duration grazing system was simulated over a 2-year period after a spring and fall introduction of infestated animals using a model depicting both temporal and spatial processes involved in host-parasite-landscape interactions. The extensive SDG system was infested for 639 and 424 days for spring and fall introductions, respectively. The intensive SDG system was continuously infested throughout the 24-month simulation. Although the intensive SDG system was continuously reinfested, there were more frequent tick-free periods in the fall introduction than the spring introduction. These simulations indicate that rest periods exceeding 150 days are necessary to minimize the rate and extent of spread of ticks in variable rotational grazing systems. These considerations are pertinent to the goals of both control and eradication strategies.
    • Spring defoliation effects on bluebunch wheatgrass: I. Winter forage quality

      Clark, P. E.; Krueger, W. C.; Bryant, L. D.; Thomas, D. R. (Society for Range Management, 1998-09-01)
      The winter forage quality of bluebunch wheatgrass (Agropyron spicatum [Pursh] Scribn. &Smith) is generally inadequate for maintenance of wintering Rocky Mountain elk (Cervus elaphus nelsoni Bailey). Previous attempts to improve the winter forage quality of bluebunch wheatgrass by clipping and livestock grazing have achieved mixed results. We report crude protein (CP), (in vitro dry matter digestibility (IVDMD), and dry matter (DM) yield responses of bluebunch wheatgrass to 3 phenological stage/defoliation intensity treatment combinations. The study was conducted in 1993 and 1994 at 2 sites in the Blue Mountains of northeastern Oregon. Bluebunch wheatgrass was hand clipped 1 to a 7.6-cm stubble height in early June under 1 of 3 treatment combinations: 1) mid-boot/whole-plant clipped, 2) mid-boot/one-half of the plant's basal area clipped, and 3) inflorescence emergence/whole-plant clipped. Early November levels of CP and IVDMD were greater under all 3 treatments compared to an unclipped control. Mean forage quality improvement over the control was greatest in the inflorescence emergence treatment with an improvement of 1.3 percentage points for CP and 5.8 percentage points for IVDMD. Dry matter yield of the control exceeded that of all clipping treatments. Increases in forage quality resulting from forage conditioning treatments may be important to the viability of elk populations wintering on rangelands where forage quality, rather than quantity, is limiting.
    • Spring defoliation effects on bluebunch wheatgrass: II. Basal area

      Clark, P. E.; Krueger, W. C.; Bryant, L. D.; Thomas, D. R. (Society for Range Management, 1998-09-01)
      Spring livestock grazing has been suggested as a tool to improve winter forage quality of bluebunch wheatgrass (Agropyron spicatum [Pursh] Scribn. & Smith). Impacts on plant vigor and survival are important concerns associated with spring grazing. We report basal area change and mortality responses of bluebunch wheatgrass to 3 spring, 1 winter, and 3 spring + winter defoliation treatments. The study was conducted in l993 and 1994 at 2 sites in the Blue Mountains of northeastern Oregon. Basal area of individual plants was measured shortly after application of the spring treatments and again approximately 1 year after treatment. Clipping the entire basal area of bluebunch wheatgrass plants to a 7.6-cm stubble height during the mid-boot phenological stage and during the inflorescence emergence stage produced 7.0 and 7.8% declines in live basal area, respectively. Unclipped control plants and plants having only one-half their basal area clipped to a 7.6-cm stubble height during the mid-boot stage exhibited 5.2 and 18.6% increases in live basal area, respectively. Combining the mid-boot/half-plant treatment with an early winter clipping to a 2.5-cm stubble height reduced the positive live basal area response to 6.0%. No additional declines in live basal area relative to the spring-only treatments were detected for combinations of the early winter treatment with the mid-boot/whole plant treatment and the inflorescence emergence treatment. Experiment-wide plant mortality was only 0.2%. If managed for a moderate level of defoliation where a portion of the basal and of each bunchgrass plant is left undefoliated, livestock grazing during the boot stage should have little negative impact on the vigor and survival of bluebunch wheatgrass under environmental conditions similar to northeastern Oregon.
    • Technical note: A comparison of techniques for extracting monoterpenoids from Juniperus (Cupressaceae) species

      Owens, M. K.; Straka, E. J.; Carroll, C. J.; Taylor, C. A. (Society for Range Management, 1998-09-01)
      Concentration and composition of monoterpenoids in plant tissue affects a variety of environmental and ecological issues such as plant defenses, plant classification and phytotoxicity. Developing the techniques for extracting and estimating the concentration and composition of monoterpenoids must be species-specific because monoterpenoid storage location varies between species. Ashe juniper (Juniperus ashei Buchholz) and redberry juniper (J. pinchotti Sudw) are 2 co-occurring species which differ in palatability and preference. The objective of this study was to determine which of 2 common extraction techniques provided the best estimate of the concentration and composition of monoterpenoids in mature plant tissue. Two extraction techniques were tested by soaking crushed juniper needles in hexane solvent for 6, 12, 18 and 24 hours or by steam distilling samples for 2, 4, 6, or 8 hours. The extracts were analyzed by using 2 different analytical columns in separate gas chromatographs. The hexane solvent soak, regardless of time in the solvent yielded a lower total concentration and a decreased compositional diversity of monoterpenoids compared to the steam distillation technique. An 8-hour steam distillation yielded the greatest concentration and composition of monoterpenoids. Both types of analytical columns resulted in similar estimates of monoterpenoid concentrations and composition.
    • Technical Note: A rotary seed processor for removing pubescence from seed of prairie grasses

      Vogel, K. P.; Masters, R. A.; Callahan, P. J.; Grams, K. (Society for Range Management, 1998-09-01)
      Many of the perennial prairie grasses that are used in restoration plantings in the central Great Plains have seed appendages such as awns and pubescence that make seed now through planters difficult. We have developed a rotary seed processor that efficiently processes small breeder or experimental lots of seed that can then be easily planted with small plot cone planters or conventional planters. The processor consists of a metal cylinder that is lined with corrugated rubber and a rotating center shaft with rubber paddles. Processing can be controlled by varying shaft rotation speed and processing time. A top-opening, full length trap door allows for easy loading and the cylinder can be inverted to dump out processed seed. The processor has been used successfully for several years on big bluestem [Andropogon gerardii Vitman], indiangrass [Sorghastrum nutans (L) Nash], little bluestem [Schizachyrium scoparium (Michaux) Nash], prairie sand reed [Calamovilfa longifolia (Rook.) Scribner] , and blue grama [Bouteloua gracilis (Willd. ex Kunth) Lagascaex Griffiths] seed. By removing seed appendages and pubescence, seed bulk is reduced and seed density and flow ability are improved. The processing operation is relatively gentle and seed germination per unit weight of seed is improved.
    • Technical Note: Rainfall simulator runoff hydrograph analysis

      Frasier, G. W.; Weltz, M.; Weltz, L. (Society for Range Management, 1998-09-01)
      Rainfall simulators have been used more than 50 years to evaluate hydrologic parameters. The generated runoff hydrograph is a continuous integration of all factors that affect runoff flow. The complexity and interaction of site factors on runoff and infiltration processes makes it difficult to identify a single component of the hydrograph that accurately characterizes the entire runoff event. A technique was developed to separate the runoff hydrograph into segments representative of different portions of the flow event. Each segment grouping is analyzed for treatment and/or site factor differences or influences on the runoff. Comparing the treatment or site impacts on each hydrograph component allows a more detailed interpretation of the runoff and infiltration processes. This approach to runoff hydrograph analysis makes it possible to quantitatively assess differences in rainfall simulator runoff results and provide insight into why hydrographs may be similar or different.
    • Variations in nutritional quality and biomass production of semiarid grasslands

      Corona, M. E. P.; de Aldana, B. R. V.; Criado, B. G.; Ciudad, A. G. (Society for Range Management, 1998-09-01)
      The effect of the growing season and topographic zone on biomass production, protein content, cell content (CC), lignin, cellulose, hemicellulose, digestibility (DMD), and mineral element concentrations (P, K, Ca, Mg, Na, Mn, Fe, Cu, Zn) were studied in herbage samples collected from semiarid grasslands in Central Western Spain. Protein and mineral contents decreased as the growing season progressed whereas fibre properties tended to increase. Topographic gradient significantly affected peak biomass production, fibre properties, protein and mineral contents. Stepwise multiple regression showed that the prediction of biomass production on these areas was related to cellulose, Na, Fe, and Mg contents in the grassland community whereas fibre properties were mainly predicted by Ca, Na, and Cu. Principal component analysis indicated that the temporal evolution (component II) of the organic variables determined pasture quality whereas most of the variation in mineral content was related to the topographical gradient (component I). Some organic and inorganic parameters may cause deficiencies in cattle grazing en the upper and middle zones, mostly at the end of the growing season. The data suggest that information about the temporal and spatial variations of the production and nutritional quality of semiarid grassland is necessary for making correct management.