• 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.
    • 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.
    • 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.