• Viewpoint: Sample adequacy for point analysis depends on the objectives

      Ortiz, M.; Ames, M. H. (Society for Range Management, 1992-11-01)
      Editorial on "An evaluation of sample adequacy for point analysis of ground cover," Journal of Range Management, vol. 43, p. 545-549.
    • Vegetation differences in desert shrublands of western Utah's Pine Valley between 1933 and 1989

      Yorks, T. P.; West, N. E.; Capels, K. M. (Society for Range Management, 1992-11-01)
      Changes in rangeland vegetation integrate the consequences of livestock grazing intensity and possible climate change, as well as other factors. Because vegetation changes tend to be very slow in dry environments, observational time scales that exceed a human generation are needed to separate real trends from year-to-year, weather-driven variability. An exhaustive literature search for valid starting points within the Intermountain region revealed a unique quantitative study that was more than 50 years old. In 1933, vegetation along a 37-km transect in southern Pine Valley, Utah, was read from 19-m2 plots located every 42 m. The only intentional, local management treatment in the interim has been moderation of domestic livestock grazing pressure. During a period climatically and phenologically similar to the original study, we re-examined representative segments of this transect by a more detailed updating of the original "square-foot-density" method. We found that vegetation type boundaries and ecotones were little changed after 56 years. However, canopy cover was dramatically greater in 1989, in some cases by more than tenfold for several perennial grasses, and less so for shrubs. Substantially greater understory cover as a relative proportion of total plant cover occurred in 1989 in all vegetation types examined. Some of the observed positive shifts of dominance/diversity are contrary to widely accepted expectations in the literature.
    • Use of artificial mineral licks by white-tailed deer in Louisiana

      Schultz, S. R.; Johnson, M. K. (Society for Range Management, 1992-11-01)
      We examined white-tailed deer (Odocoileus virginianus) use of artificial mineral licks on 3 properties in southcentral Louisiana. High deer use of licks extended longer into summer and fall than reported for areas in more northern latitudes. Estimated monthly mineral consumption averaged 538.0 g/deer (SE = 70.8) and was associated with total moisture and crude protein reported for native plants on forest range in central Louisiana. Consumption from individual licks was positively associated with adjacent soil P concentration (P < 0.001).
    • Technical Note: An evaluation of 4 clovers and Italian ryegrass for white-tailed deer

      Johnson, M. K.; Schultz, S. R. (Society for Range Management, 1992-11-01)
      We evaluated winter weight gain of captive male white-tailed deer (Odocoileus virginianus) that grazed pastures of berseem (Trifolium alexandrinium L.), white (T. repens L.), crimson (T. incarnatum L.), or subterranean (T. subterraneum L.) clover their first winter and pastures of berseem, white, or crimson clover or Italian ryegrass (Lolium multiflorum Lam.) their second winter. Weight gains the first winter (14.7 +/- 0.7kg) did not differ (P>0.10) among the clovers. Bucks that grazed berseem, white, or crimson clover the second winter gained 3.0 +/- 0.5 kg, while bucks that grazed Italian ryegrass gained 0.9 +/- 0.9 kg.
    • Salinity effects on forage quality of Russian thistle

      Fowler, J. L.; Hageman, J. H.; Moore, K. J.; Suzukida, M.; Assadian, H.; Valenzuela, M. (Society for Range Management, 1992-11-01)
      Russian thistle (Salsola iberica Sennen and Pau), a common weed found on overgrazed rangelands, abandoned farmlands, and other disturbed sites in the western United States, is often grazed by livestock and in times of drought has been extensively harvested for hay. Much of the land where Russian thistle grows in the western United States has a salinity hazard. The purpose of this study was to determine the effects of salinity stress on forage quality of Russian thistle. Russian thistle plants were grown in a greenhouse in sand culture irrigated with salinized nutrient solutions (electrical conductivities of 1.3, 10.6, 19.5, 26.8, and 33.9 dS/m) prepared with NaCl and CaCl2 (2:1 molar ratio). Chemical indices of forage quality (total N, neutral detergent fiber, acid detergent fiber, acid detergent lignin, nitrate, and oxalates) at 2 growth stages (early flower and full flower) were determined. Forage quality of Russian thistle, as measured by total N and fiber constituents, improved with increasing salinity. Mineral ash content increased with salinity stress at both growth stages but was reduced slightly by increasing maturity. Nitrate levels increased at early flower but decreased at full flower with increasing salinity, whereas oxalate-levels at both growth stages were reduced by salinity. Neither component was of sufficient magnitude to be toxic to ruminants. These results indicate that salinity stress is not detrimental to forage quality of Russian thistle but tends to improve it.
    • Reply to Ortiz and Ames' Viewpoint: Sample adequacy for point analysis depends on the objectives

      Hofmann, L.; Ries, R. E. (Society for Range Management, 1992-11-01)
      Editorial reply to "Viewpoint: sample adequacy for point analysis depends on the objectives," Journal of Range Management, vol. 45, no. 6, p. 595.
    • Relationship of fire behavior to tallgrass prairie herbage production

      Bidwell, T. G.; Engle, D. M. (Society for Range Management, 1992-11-01)
      Little evidence has been found to relate fire intensity to herbaceous vegetation response. Our objective was to determine if components of post-fire herbaceous standing crop in a tallgrass prairie could be related to either fire behavior variables or to time-temperature relationships. We used canonical correlation to relate standard fire behavior variables (fireline intensity, rate of spread, and heat per unit area) and time-temperature relationships (degree seconds at 3 vertical strata) to post-fire components of the herbaceous standing crop of tallgrass prairie. Spring headfires and backfires were applied to 10 X 20-m plots on a moderately grazed, shallow prairie range site in good to excellent range condition. The first canonical correlation of the 3 fire behavior variables and the standing crop variables generally indicated a strong relationship between the 2 sets of variates. The canonical correlation between the degree seconds and standing crop sets of variates was slightly less than the canonical correlation between the fire behavior parameters and standing crop. Neither the fire behavior canonical variate nor the degree second canonical variate was strongly related to any single component of the June or August standing crop, but this study demonstrates that fire behavior is a factor affecting community herbaceous vegetation response to fire in tallgrass prairie.
    • Recent rates of mesquite establishment in the northern Chihuahuan Desert

      Gibbens, R. P.; Beck, R. F.; McNeely, R. P.; Herbel, C. H. (Society for Range Management, 1992-11-01)
      Honey mesquite (Prosopis glandulosa Torr. var. glandulosa populations continue to expand and become more dense, even on areas once "successfully" treated either with herbicides or by bulldozing in southern New Mexico. Areas treated from 1958-1964 for mesquite control on the USDA-ARS Jornada Experimental Range and the New Mexico State University College Ranch were sampled to determine mesquite density changes. On herbicide treated areas sampled in 1976 and again in 1988, mesquite densities increased 10% to 128% and had densities from 67 to 494 plants/ha. Two areas treated by either bulldozing or fenuron in 1959-60, and with original kills near 100%, had an average density of 377 plants/ha by 1988, with an establishment rate of 13.5 plants/ha/year. On the College Ranch, mesquite densities increased 11%, from 130 (1982) to 147 (1988) plants/ha. Only 19% of a cohort of mesquite seedlings which germinated in 1989 were still alive in May 1990. Even though only a small percentage of the mesquite that germinated survived into the second year, this is enough to change former grasslands into mesquite-dominated rangelands.
    • Range animal diet composition in southcentral Wyoming

      Ngugi, K. R.; Powell, J.; Hinds, F. C.; Olson, R. A. (Society for Range Management, 1992-11-01)
      Because of the ongoing controversy about shrub forage value for different ungulates and significance of the shrub communities for spring-fall grazing in southcentral Wyoming, the relative importance of various forage classes was determined by fecal analyses in the spring, summer, and fall diets of pronghorn (Antilocarpa americana Ord), mule deer (Odocoileus hemionus hemionus), elk (Cervus elaphus), cattle (Bos taurus), and domestic sheep (Ovis aries) in the mountain brush and Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young) plant communities. Mountain big sagebrush (A.t. ssp. vaseyana Rydb. Beetle) comprised 76% of pronghorn spring diets in the mountain brush plant community, and Wyoming big sagebrush comprised 91% of the pronghorn spring diets in the Wyoming big sagebrush plant community. Antelope bitterbrush (Purshia tridentata Pursh.) comprised about 80 to 90% of the pronghorn and deer summer and fill diets in the mountain brush plant community. Graminoids, primarily Bromus, Carex, Juncus, and Stipa spp., made up 80+% of elk, cattle, and sheep diets in either plant community. Forbs and shrubs other than sagebrush or bitterbrush were a minor component of either plant community and diets of any of the 5 kinds of animals. A shrub management program to maintain species diversity while increasing bitterbrush and graminoid production under common use grazing by both browsers and grazers is recommended for this area.
    • Mechanical rejuvenation to dampen seasonal variation in chemical composition of browse

      Reynolds, J. P.; Fulbright, T. E.; Beasom, S. L. (Society for Range Management, 1992-11-01)
      Nutritional quality of range plants eaten by white-tailed deer (Odocoileus virginianus Raf.) in southern Texas is lowest during summer and fall. Nutritional quality of shrub regrowth is typically elevated for several months following top growth removal. We tested a strategy to temper the summer-fall decline in nutritional quality of guajillo (Acacia berlandieri Benth.) and blackbrush acacia (A. rigidula Benth.) by roller chopping separate, adjacent portions of the habitat each year during early July. Parallel strips of brush 40-m wide and about 1.6 km-long were roller chopped during 1986-87 in a pattern of alternating roller-chopped and nontreated strips. Leaves and twig tips of nontreated plants and of regrowth from roller-chopped plants were collected bimonthly and analyzed for crude protein (CP) and in vitro organic matter digestibility (IVOMD). Crude protein of guajillo leaves and stems was higher for regrowth than for nontreated plants for 6 and 8 months, respectively, after roller chopping in 1987, and IVOMD of leaves increased for 2 months. The CP of blackbrush leaves from regrowth was higher than CP of leaves from nontreated plants for 6 months after roller chopping in 1987 but IVOMD temporarily decreased. Roller chopping in early July may temporarily increase CP of guajillo browse during the late summer and early fall nutritional stress period, but it is not a promising method for rejuvenation of blackbrush browse.
    • Lehmann lovegrass live component biomass and chemical composition

      Cox, J. R. (Society for Range Management, 1992-11-01)
      Lehmann lovegrass (Eragrostis lehmanniana Nees), a perennial bunchgrass from southern Africa, is replacing native grasses in Arizona. After the invasion, biomass production and quality may change. This study was conducted to determine the production and chemical composition of live Lehmann lovegrass leaves, culms, and seedheads during wet and dry years. During 3 years, green leaf biomass peaked at 78 +/- 14 g m-2 (mean +/- SE) in early August, green culms peaked at 103 +/- 21 g m-2 in mid October, and green seedheads peaked at 18 +/- 12 g m-2 in mid August. Leaf and culm growth peaks correspond with low crude protein (2.5%) and moderate phosphorus (0.23-0.25%) levels while seedhead growth peaks correspond with high crude protein (7-10%) and moderate phosphorus (0.19-0.29%) levels. There were no crude protein and phosphorus peaks in green culms. In Lehmann lovegrass forage, crude protein should meet animal requirements for about half the year while phosphorus should be adequate throughout the year. In native forages, crude protein is adequate throughout the year because animals selectively graze forbs, grasses, and shrubs but phosphorus does not meet animal requirements except in mid-summer.
    • Influence of saline water on intake, digesta kinetics, and serum profiles of steers

      Kattnig, R. M.; Pordomingo, A. J.; Schneberger, A. G.; Duff, G. C.; Wallace, J. D. (Society for Range Management, 1992-11-01)
      Nine yearling Holstein steers (avg weight 234 kg) were used to evaluate the influence of water salinity on feed and water intake, as well as several ruminal and serum characteristics. The ruminally cannulated steers were individually fed low-quality mixed hay simulating a range diet. Steers were assigned randomly to receive either control (C) water containing 350 ppm total dissolved solids (TDS) or a treated water (HS) containing 2,300 ppm TDS. The experiment included a 14-day adjustment period and a 15-day measurement period. High-saline water did not affect (P = 0.18) feed or water intake, although there was a tendency for greater consumption of both feed and water in HS steers. The HS steers had slower (P = 0.10) particulate passage rates and longer (P = 0.06) rumen retention times on day 1 of the measurement period, indicating possible differences in particle density and (or) particle size. On day 1, undigested dry matter (DM) fill was greater (P = 0.05) in HS steers compared with C (80.7 vs 61.5 g/kg BW); similar trends occurred on day 8. The HS steers also had greater (P = 0.02) rumen fluid volumes, but similar (P = 0.45) fluid dilution rates compared with C steers. No in situ DM disappearance differences were detected (P greater than or equal to 0.38) at incubation times ranging from 12 to 72 hours. No clinical or sub-clinical toxicological symptoms were observed in HS compared with C steers. This study suggests that cattle can ingest saline water containing 2,300 ppm TDS on a short-term basis with no adverse effects.
    • Forb and shrub effects on ruminal fermentation in cattle

      Arthun, D.; Holechek, J. L.; Wallace, J. D.; Gaylean, M. L.; Cardenas, M. (Society for Range Management, 1992-11-01)
      One experiment involving steers fed low-quality grass diets singly and mixed with native forbs, native shrubs, or alfalfa (Medicago sativa L.) was conducted to compare the influence of these diets on ruminal fermentation. Native forbs used in our study were a 50:50 mixture of scarlet globemallow (Sphaeralcea coccinea Nutt.) and leatherleaf croton (Croton pottsii Lam.); native shrubs were a 50:50 mixture of fourwing saltbush (Atriplex canescens [Pursh.]) and mountain mahogany (Cercocarpus montanus Raf.). Neither passage rate of indigestible neutral detergent fiber nor fluid passage rate differed (P > .10) among the 4 diets. Ruminal pH did not differ (P > .10) among diets, and ruminal ammonia concentrations differed (P < .10) inconsistently among diets, depending on time after feeding. Likewise, total ruminal volatile fatty acid (VFA) concentrations did not differ (P > .10) among diets. Except for butyrate [less (P < .05) with alfalfa], proportions of individual VFA showed little difference among diets. Based on these data, adding forbs or shrubs with low-quality forage diets appears to elicit few changes in ruminal digests kinetics and fermentation patterns compared to including alfalfa hay.
    • Emergence and seedling survival of caldén in the semiarid region of Argentina

      Peláez, D. V.; Bóo, R. M.; Elia, O. R. (Society for Range Management, 1992-11-01)
      Caldén (Prosopis caldenia Burk.) is one of the woody species that is increasing in abundance due to poor grazing management in the semiarid region of central Argentina. The objectives of this work were to evaluate emergence and seedling survival of caldén under grazed-low herbaceous foliar cover, and ungrazed-intermediate and ungrazed-high herbaceous foliar cover. Seedling emergence was recorded weekly after 3 planting dates: October 1987, September 1988, and October 1989. Seedling survival was recorded every 2 weeks until all seedlings died. Precipitation, soil water potential, and soil temperature were monitored during the study period. Since caldén only reproduces from seeds, optimal conditions for germination under different controlled photoperiod and temperature regimes were also studied. In the laboratory, greatest germination of freshly harvested unscarified seeds occurred at a diurnally alternating temperature regime of 15 and 30 degrees C with light provided for 9 hours. Lead germination occurred at 15 degrees C and continuous darkness. Acid scarification significantly increased germination percentage and germination rate. Unscarified seeds incubated in light exhibited a lower rate of germination than scarified seeds under all temperatures. In the field, soil water availability was usually similar among the 3 experimental conditions. Soil temperature was only occasionally higher in the grazed-low herbaceous cover site. Only for 1987 data, emergence was greater on the grazed area with relatively low herbaceous foliar cover and similar within the ungrazed area. Treatment effect was very little on seedling survival, being lower in the grazed area for only 2 evaluation dates in 1989. Regardless of treatment the emerged seedlings survived 40 days on the average. The highest caldén seedling mortality was always coincident with higher soil temperature and lower soil water availability.
    • Clipping frequency and intensity effects of big bluestem yield, quality, and persistence

      Forwood, J. R.; Magai, M. M. (Society for Range Management, 1992-11-01)
      This study was initiated to determine the effects of defoliation frequency (based on amount of growth present), intensity, and length of grazing season on quantity and quality of big bluestem (Andropogon gerardi Vitman) in the Southern corn belt and to provide further data regarding the reasons for rapid quality decline of warm-season grasses. Three clipping frequencies (when plants reached heights of 30, 41, 51 cm) at 2 intensities (stubble heights of 10 and 20 cm) were imposed on established plots of pure big bluestem (cv. Kaw). Harvest season length was studied by terminating clipping on 15 August and 15 September as 2 separate treatments. Two years of data indicated that big bluestem regrows insufficiently after 15 August to warrant additional harvests under the imposed managements. Prolonged regrowth and leaving a short stubble of 10 cm resulted in greatest yield. Short stubble led to greater reductions in nonstructural carbohydrates, but did not damage the stand compared to pre-study measurements. Nonstructural carbohydrate levels and stand composition improved with taller stubble. In vitro dry matter digestibility and crude protein were higher on treatments clipped to leave a 10-cm stubble. The greatest proportion of leaves resulted from treatments where a 20-cm stubble remained. These results agree with studies indicating that leaf maturity is more responsible for lower quality forage than is the amount of stem material present in the stand. Our results indicate heavy use can be more safely accomplished in the Southern corn belt than for areas to the west because big bluestem can be more intensively defoliated in the Southern corn belt (10-cm) than that recommended for other areas (20 to 40 cm).
    • Cattle diets in tall forb communities on mountain rangelands

      Ralphs, M. H.; Pfister, J. A. (Society for Range Management, 1992-11-01)
      Thirteen grazing studies have recently documented diet botanical composition of cattle in tall forb plant communities on mountain rangelands. In forb-dominated plant communities, cattle selected forbs in proportion to their availability, (46 to 83% of their diets). In grass-dominated communities, forbs comprise only 11 to 32% of diets. On a landscape scale cattle preferred and spent proportionally more time grazing in forb-dominated communities. Taken together, these studies indicate that cattle have a wide acceptability for forage classes and can effectively utilize forb-dominated high mountain rangelands.
    • Bunchgrass basal area affects selection of plants by cattle

      Ganskopp, D.; Rose, J. (Society for Range Management, 1992-11-01)
      Cattle are selective foragers in response to several plant attributes. We tested hypotheses that caespitose plants of various basal areas were equally susceptible to herbivory and were defoliated with equal intensity by cattle. Five-hundred crested wheatgrass (Agropryon desertorum (Fischer ex Link) Schultes) plants, distributed among 10 basal area classes, were monitored for frequency and level of utilization after approximately 74% of all plants in pastures were grazed by cattle. Plants with < 25-cm2 basal area were less likely, and plants between 65 and 105-cm2 more likely to be grazed than other classes. Ninety-one percent of the 65 to 85-cm2 basal area plants were defoliated, while only 48% of those < 2 .5 cm2 were grazed. The fact that mid-size plants occurred least often but were defoliated most often lends further credence to the selective grazing hypothesis. Less frequent use by cattle of plants < 2 5-cm2 basal area may enhance chances of seedling establishment and survival of smaller established plants or remnants of deteriorating tufts. Among grazed plants, however, smaller plants endured higher utilization by weight than the overall population. Utilization was equal among other size classes. Because forage yield per unit of basal area declined as plant size increased, cattle probably forage most efficiently by selecting bite-size plants. Researchers using single plants, tiller, or leaves as experimental units should note that varying sized tufts are not equally likely to be defoliated, and plants less than 25-cm2 basal area may receive greater than average levels of utilization from free-ranging cattle under light to moderate utilization levels. These aspects of livestock grazing behavior and research objectives should be considered in selection of experimental units.
    • Bobwhite habitat use under short duration and deferred-rotation grazing

      Wilkins, R. N.; Swank, W. G. (Society for Range Management, 1992-11-01)
      A study was conducted in the South Texas Plains to contrast the short-term impacts of short duration grazing (SDG) and deferred-rotation grazing (DG) systems on habitats for northern bobwhites (Colinus virginianus). Foliar cover, species richness, and structural attributes of the vegetation were compared at radio-location sites (quail-used) and sites along random transects (available) within and between the 2 grazing systems. Quail-used sites were characterized by increased species richness, forb cover, and bare ground and decreased plant height and litter accumulations. Principal components analysis revealed that available sites on the SDG during the fall and winter were scored higher along a habitat gradient which had greater species richness and forb cover combined with diminished litter accumulations. This habitat gradient explained 41% of the variation in the ground layer variables. In addition, mark-recapture studies suggested positive population responses on the SDG during the first year following its initiation. Short-term improvements in bobwhite habitats may be realized by initiating SDG on some semiarid rangelands.
    • Adverse effects of pine needles on aspects of digestive performance in cattle

      Pfister, J. A.; Adams, D. C.; Wiedmeier, R. D.; Cates, R. G. (Society for Range Management, 1992-11-01)
      Pine needles from ponderosa pine (Pinus ponderosa Lawson) consumed by cows during winter can cause abortions. Our study determined the nutritional impact of pine needles given to steers intraruminally. In Trial 1, 12 steers were given either grass hay alone (CONT), 15% pine needles (15PN), or 30% pine needles (30PN) substituted for hay, as fed basis. In Trial 2, a 4 X 4 Latin square design was used with 4 steers. Treatments were: (1) control-grass hay alone (CONT); (2) grass hay plus 454 g/day of cottonseed meal (CSM); (3) pine needles substituted for 40% (as fed basis) of the hay (PN); and (4) pine needles (40%) plus 454 g/day of CSM (PNCSM). In Trial 1, dry matter intake (DMI), fecal N, and DM digestibility were not affected by either 15PN or 30PN. N intake and N digestibility were reduced (P < 0.07) by 30PN. Fluid dilution rate (FDR) and fluid outflow rate (FOR) were depressed (P = 0.10) by 30PN. Total VFA and ruminal ammonia-N also were depressed by 30PN. In Trial 2, the PN treatment adversely affected DMI, N intake, and all digestibility coefficients, and elevated fecal N. FDR, FOR, and turnover time (TOT) were reduced by 40% PN. Total VFA were increased by PN, while ammonia-N concentrations were reduced. Cottonseed meal had few effects on rumen variables, and there were no CSM X PN interactions. We conclude that pine needles severely affect cattle nutrition, particularly N intake and digestibility and fluid rate of passage. Cottonseed meal, at 1 kg/day, does not ameliorate the adverse effects of pine needles. Fifteen to 30% pine needles in cattle diets appears to be the threshold level for toxic effects on ruminal fermentation.