• An Updated Procedure for Cecal Cannulation in Sheep and Cattle

      Caton, J. S.; Krysl, L. J.; Freeman, A. S.; Ruttle, J. L.; Branine, M. E. (Society for Range Management, 1987-07-01)
      Fifteen cattle (236-500 kg) and 38 sheep (36-55 kg) were fitted with 2 types of indwelling cecal cannulae. Cannulae were made of either clear silicone or plastic tubing. The surgery was conducted in a one-step procedure that involved pharmaceuticals and equipment that were readily available. Results indicated a success rate of 67% (33% failure due to inability to locate the cecum at the time of surgery) in cattle and 100% in sheep. Both cannula types tested were acceptable, but the cannula made from plastic tubing was more desirable because it was less bulky, more durable, and easier to construct. Animals fitted with cecal cannulae appeared to be healthy and to have normal life spans.
    • Allelopathic Effects of Kochia on Blue Grama

      Karachi, M.; Pieper, R. D. (Society for Range Management, 1987-07-01)
      The allelopathic effects of kochia aqueous extracts found in kochia (Kochia scoparia L. Roth.) on seed germination and seedling growth of blue grama (Bouteloua gracilis [H.B.K.] Lag.) were studied in laboratory experiments. Extracts were from regrowth, whole tops, leaves, and stems, representing the vegetative and reproductive phenologies. Inhibition of seed germination did not occur. However, seedling radicle and shoot growth were significantly (P<0.05) affected. Inhibition declined significantly with concentrations of the solutions and advancing phenological stage. Similarly, hot water extracts inhibited growth more than cold water extracts. The data suggest possible inhibitory effects of kochia litter under field conditions, but detailed studies are lacking.
    • A New Sticky Trap for Monitoring Seed Rain in Grasslands

      Huenneke, L. F.; Graham, C. (Society for Range Management, 1987-07-01)
      The use of an inexpensive, commercially available device as a sticky trap for capturing dispersing seeds in the field is described. Trap performance in capturing seeds under various conditions is evaluated. The traps perform well in capturing small, lightweight seeds, particularly those with awns or ornamentation, as would be typical of many grassland plant species. The adhesive surface of the traps retains its effectiveness when moist, and in the hot, dusty conditions of the field. However, the traps have poor rates of capture for certain seed types, and for seeds dropped from considerable heights. These limitations of performance, which are probably shared with other types of sticky traps for seeds, must be considered when sticky traps are used to evaluate seed rain.
    • A Dynamic Programming Application for Short-Term Grazing Management Decisions

      Rodriguez, A.; Roath, L. R. (Society for Range Management, 1987-07-01)
      This study emphasizes short-term management decisions that are made in a yearling cattle operation in northeastern Colorado. Empirical equations describing forage and animal growth were coupled with marketing and supplementation alternatives. Four cases were modeled with high and low stocking densities and partial or total sales strategies. Net present value of yearling steer sales were maximized using dynamic programming. Early sale of cattle was an economically favorable alternative because of decreasing daily gains toward the end of the grazing season (September-October) and decreasing steer prices. Supplementation during September-October was also profitable to offset the decreasing trend in average daily gain caused by declining forage quality. Under the high stocking density and partial sales strategy, early sales regulated standing crop left at the end of the grazing season. Under the low stocking density and partial sales strategy, early sales partially offset net return losses for those animals that had to be sold at the traditional marketing date. The total sales strategy favored sales of livestock 2 weeks before traditional marketing under low and high stocking density and partial sales strategy. Net present values per pasture were slightly larger for the total sales strategy than the partial sales strategy using both low and high stocking densities.
    • 14- Vs. 42-Paddock Rotational Grazing: Forage Quality

      Heitschmidt, R. K.; Dowhower, S. L.; Walker, J. W. (Society for Range Management, 1987-07-01)
      Research was initiated at the Texas Experimental Ranch in 1981 to quantify the effects of 2 livestock densities on forage quality in a rotational grazing (RG) treatment. Livestock densities evaluated were equivalent to 14 and 42-paddock RG treatments. Baseline data were collected in 1981 from 3 adjacent 30-ha paddocks in a 465-ha, 14-paddock, cell designed RG treatment stocked at a rate of 3.6 ha/cow/year. Near the beginning of the 1982 growing season the center paddock was subdivided into three, 10-ha paddocks to establish the RG-42 treatment. Herbage standing crop was harvested before and after each grazing event during the 40-month period, separated by species or species group into live and dead tissue, and each fraction analyzed for percentage crude protein (CP) and organic matter digestibility (OMD). Livestock density had minimial effect on forage quality. Live tissue was of higher quality than senesced tissue regardless of plant species. Increases and decreases in overall quality during grazing periods were positively associated with rates of plant growth. Number of periods when forage quality increased or decreased during grazing and magnitude of change were unaffected by treatment. Lack of significant treatment effects on forage quality is attributed to the general absence of significant treatment effects on forage production, species composition, and live/dead ratios.