• Research Observation: Chemical repellants to reduce grazing intensity on reclaimed sites

      Osko, T. J.; Hardin, R. T.; Young, B. A. (Society for Range Management, 1993-09-01)
      Revegetation of disturbed rangelands in western Canada is severely impeded by cattle grazing. Fencing to protect emergent vegetation is costly and restricts animal movement. Chemically repelling cattle from emergent vegetation may provide a convenient and economical alternative to fencing. This study determined whether certain repellents could reduce grazing intensity on vegetation to which they were applied compared to untreated vegetation. Canopy measurements were used to compare grazing intensity. Three trials were conducted on reclaimed land within the Aspen Parkland region of central Alberta. Time since reclamation was over 10 years in Trial A, 2 years in Trial B, and 3 weeks in Trial C. Pregnant mares' urine, Hinder® (150 mg ml-1 ammonium soaps), Skoot® (120 mg mi-1 tetramethylthiuram disulfide), and Deer-Away Big Game Repellent® (37% putrescent egg solids) were evaluated. Two concentrations of each repellent were sprayed onto 1 X 3-m treatment plots randomized within blocks replicated 4 to 6 times. Plot canopies were measured either by gently resting a sheet of plastic laminate over the canopy, or by lowering a sliding bar attached perpendicularly to a meter stick until it contacted the uppermost leaves of the canopy, and recording the height of the sheet or bar above the soil surface. Canopies of plots treated with Big Game Repellent® were taller than control plot canopies on each measurement date in all trials, indicating grazing was reduced. Big Game Repellent® plots were also generally taller than plots treated with other repellents. Canopies of plots treated with pregnant mares' urine, Hinder®, and Skoot® generally did not differ from control plots, nor did they differ from each other in any trial. Low repellent concentrations did not reduce grazing in any trial, but high concentrations reduced grazing in all trials. Repellent effectiveness was not permanent since all canopy measurements became shorter with time. Big Game Repellent® was effective in reducing grazing intensity by cattle, but practical use of repellents for grazing management requires further investigation.
    • Seasonal grazing of locoweeds by cattle in northeastern New Mexico

      Ralphs, M. H.; Graham, D.; Molyneux, R. J.; James, L. F. (Society for Range Management, 1993-09-01)
      Locoweed poisoning generally occurs in early spring. We evaluated cattle grazing of woolly locoweed (Astragalus mollissimus var. mollissimus Torr.) at Gladstone, N.M., and of white locoweed (Oxytropis sericea Nutt. ex T&G) at Capulin, N.M., through the spring and into early summer as the phenological development of warm-season grasses progressed from dormancy to rapid growth. Diets of 8 mature cows were quantified by bite count at each location. Cattle initially rejected woolly locoweed at Gladstone, even though it was the only green forage available in late March and early April. Gladstone cattle were then restricted to a small 7-ha pasture where high grazing pressure and limited feed forced them to graze woolly locoweed (41% of bites). When these cows returned to a larger pasture of unlimited forage availability, they continued eating woolly locoweed (23% of bites). At Capulin, cattle with a history of eating locoweed (loco-eaters) consumed more white locoweed (23% of bites) thin cattle without a history of eating locoweed (6% of bites) during the April grazing period. When warm-season grasses started rapid growth and locoweed matured in June, cattle ceased grazing both locoweed species.
    • Viewpoint: "Invisible colleges" and citation clusters in stocking rate research

      Hart, R. H. (Society for Range Management, 1993-09-01)
      Research on the response of livestock gain to stocking rate tends to cluster into 5 "invisible colleges", represented by 5 citation networks which only occasionally intersect. Each college is built around a paradigm of the stocking rate-gain response as developed in 2 key papers sharing 1 or more authors. Researchers tend to cite the paradigm developed by authors in their field of research or in their geographic area. Therefore conficting pardigms have existed side-by-side for decades, an unusual occurrence in most fields of science. Research is needed to critically evaluate the empirical and conceptual soundness of these paradigms.