Journal of Range Management, Volume 48, Number 2 (March 1995)
http://hdl.handle.net/10150/635505
2024-03-28T07:55:27ZJournal of Range Management, Volume 48, Number 2 (March 1995)
http://hdl.handle.net/10150/650550
Journal of Range Management, Volume 48, Number 2 (March 1995)
Complete digitized issue.
1995-03-01T00:00:00ZViewpoint: The rangeland condition concept and range science's search for identity: A systems viewpoint
http://hdl.handle.net/10150/644502
Viewpoint: The rangeland condition concept and range science's search for identity: A systems viewpoint
Scarnecchia, D. L.
This paper analyzes the rangeland condition concept, and discusses how the search for a general concept has been part of the larger search for the identity of range science. It distinguishes between the concept and the assessment of rangeland condition, and distinguishes between the concept and ecological theories used in condition assessment. It proposes a general condition concept of modular character in which different ecological theories and field data are interchangeable components applied locally on appropriate, specific areas. It discusses past distinctions between range management and range science, implores the development of range management science, and discusses efforts needed in research, education, and administration to pursue its development. It interprets past and current events related to range science, including the advent of rangeland health, and discusses their relationships to range science's unfulfilled development as a management science. The paper encourages systematic design of concepts needed to allow range science to fulfill its philosophical potential as a management science.
1995-03-01T00:00:00ZSupplement and forage effects on fecal output estimates from an intra-ruminal marker device
http://hdl.handle.net/10150/644477
Supplement and forage effects on fecal output estimates from an intra-ruminal marker device
Hollingsworth, K. J.; Adams, D. C.; Klopfenstein, T. J.; Lamb, J. B.; Villalobos, G.
Three experiments were conducted to evaluate effects of supplemental protein and forage on marker estimated fecal output using an intraruminal continuous release marker device in grazing steers. In experiment 1, twelve steers were assigned to 3 treatments and fecal collections were made during a 6-day period in December 1990 and again in February 1991. Treatments were: 1) range forage only, 2) range forage + 0.32 kg protein/day from a 70% soybean meal - 30% wheat pellet, and 3) range forage + 0.32 kg crude protein/day from 15.1% meadow hay. Fecal output estimates derived from the marker device were similar (P > 0.10) for all treatments and both periods. Fecal estimates derived from the marker device were greater (P < 0.01) than fecal output from total fecal collection (3.5 kg/day vs 2.7 kg/day); the correlation between estimates from fecal collection and the marker device was 0.85. In experiment 2, ten steers were assigned to treatments 1 and 2 of experiment 1 during December 1991. Fecal output derived from the marker device was similar (P > 0.10) for the 2 supplement treatments. Fecal output estimates were greater (P < 0.10) for the marker device than fecal collection (1.80 kg/day vs 11.63 kg/day); the correlation between estimates from the marker device and total collection was 0.94. In experiment 3, fecal output was derived from the marker device during three 5 day collection periods. Steers grazed upland range in July (green immature forage) and September (cured mature forage) and grazed subirrigated meadow (immature regrowth) in October. Fecal output estimates from the marker device were different (P < 0.05) between collection periods, (e.g., forage sources). When compared to total fecal collection, the marker device underestimated fecal output on range in July (P < 0.01, 2.1 kg/day vs 2.5 kg/day) and on meadow in October (P < 0.01, 2.6 kg/day vs 3.5 kg/day). Correlations between the marker device and fecal collection were 0.93 in July and 0.99 in October, respectively. Estimates from the marker device and total fecal collection were similar (P > 0.10; r = 0.93) on range in September. Protein supplements had no effect on fecal estimates derived from chromic oxide released from a marker device, but the marker estimates were affected by forage source. Correlation between fecal collection and the marker method is high; however, total fecal collection should be used to correct fecal output derived by the marker device for each forage source.
1995-03-01T00:00:00ZSpotted knapweed seed viability after passing through sheep and mule deer
http://hdl.handle.net/10150/644473
Spotted knapweed seed viability after passing through sheep and mule deer
Wallander, R. T.; Olson, B. E.; Lacey, J. R.
Spotted knapweed (Centaurea maculosa Lam.), an introduced perennial plant, has invaded large areas of rangeland in the northwestern United States. Grazing animals may disseminate the weed by transporting seeds in their digestive system and depositing them in their feces. In this study percent viability and emergence of spotted knapweed seeds that passed through mule deer (Odocoileus hemionus hemionus) and sheep (Ovis aries) were determined. Percent viability included seeds that germinated and seeds that tested positive with tetrazolium. In the first trial, we pulse dosed 3 mule deer and 4 ewes with 5,000 spotted knapweed seeds each. Seed recovered from manure collected daily for 10 (days after dosing was tested for percent viability. We recovered 11% of the knapweed seeds from the 3 mule deer, and 4% from the sheep. Based on high variability in (0 to 26%) percent viability of recovered seed, we thought that our drying the manure at a 50 degrees C may have killed some of the spotted knapweed embryos. To determine if drying at 50 degrees C affected viability, we pulse dosed 41 rams with 5,000 spotted knapweed seeds each in a second trial. One subsample of manure was washed the same day to recover seeds and then dried at 35 degrees C, a second subsample was dried at d 50 degrees C, washed, and then dried at 35 degrees C. We recovered 17% of the spotted knapweed seeds from the 4 rams. No viable seeds were recovered from manure heated at 50 degrees C, and no viable seeds were recovered more than 2 days after dosing. Percent viability of seeds recovered from manure dried at 35 degrees C ranged from 0 to 22%. In both trials, percent viability of recovered seeds was lower compared with seeds that did not pass through animals. Sheep and mule deer can ingest, transport, and disseminate viable seeds of spotted knapweed in their feces.
1995-03-01T00:00:00Z