Grazing management affects nutrient intake by steers grazing tallgrass prairie
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CitationMcCollum, F. T., & Gillen, R. L. (1998). Grazing management affects nutrient intake by steers grazing tallgrass prairie. Journal of Range Management, 51(1), 69-72.
PublisherSociety for Range Management
JournalJournal of Range Management
AbstractIndicators of nutrient intake were compared for beef steers grazing tallgrass prairie managed with continuous grazing or 8-paddock short-duration grazing. Two replicates of each grazing system were evaluated during the 2 year study. Stocking rates for the grazing systems were similar in both years. Within each treatment replicate, 3 steers fitted with ruminal and duodenal cannulae grazed for the entire grazing season (late April through late September) with larger groups of intact steers. Rest periods for the 8-paddock cells were lengthened as the season progressed and forage accumulation rate slowed. Trials occurred in early June and early August in year 1 and early July and early September in year 2. Flow of organic matter and nitrogen at the duodenum, fecal nitrogen concentration, and fecal output were used as indicators of nutritional status. Chromic oxide was used as a flow marker. Flow of organic matter, total nitrogen, and microbial nitrogen at the duodenum in addition to fecal output were lower (P < 0.04) with short-duration grazing and indicate that forage intake and digestible organic matter intake were depressed in steers on the short-duration grazing treatment. Forage digestible organic matter intake, estimated from microbial protein flow, was 19.3% lower (P < 0.03) on short-duration grazing. Fecal nitrogen concentration was higher (P < 0.03) for steers under continuous grazing. Diet crude protein estimated from fecal nitrogen was 24.4 g kg-1 organic matter higher for continuous grazing. These results suggest that both diet nutrient composition and intake were depressed in steers in the short-duration grazing treatment. These observations partially explain the lower weight gains and higher end-of-season residual standing vegetation noted with short-duration grazing in concurrent grazing trials on these rangelands.
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Grazing systems, stocking rates, and cattle behavior in southeastern WyomingHepworth, K. W.; Test, P. S.; Hart, R. H.; Waggoner, J. W.; Smith, M. A. (Society for Range Management, 1991-05-01)Grazing systems and stocking rates are used to influence livestock grazing behavior with the intent of improving livestock and vegetation performance. In 1982, a study was initiated to determine effects of continuous, rotationally deferred, and short-duration rotation grazing and moderate and heavy stocking rates on steer gains, range vegetation, and distance traveled by and activity patterns of steers. Steers were observed from dawn to dark on 12 dates during 1983, 1984, and 1985, and activity recorded every 15 minutes. Eight steers per treatment (system X stocking rate combination) per date were observed in 1983 and 1984, and 10 per treatment in 1985. In 1984 and 1985, map locations of all steers were recorded at the same times as activity, and distance traveled summed from distances between successive map locations. In 1984, activity of 3 steers per treatment was electronically monitored during darkness. Steers grazed approximately 8.6 hr per day during daylight and 1.6 hr during darkness. Steers grazed an average of 8.9 hr/day during daylight under moderate vs 8.1 hr under heavy stocking, but stocking rate interacted with date in 1984 and grazing system in 1985. Steers traveled farther under continuous than under short-duration rotation grazing at both stocking rates in 1984, but only at the high stocking rate in 1985. Steers had to travel farther to water in the continuous pastures, and may have had to cover a greater area in an effort to select a more desirable diet, particularly under heavy stocking. These differences were not reflected in differences in gain among stocking rates or grazing systems.
Grazing systems, pasture size, and cattle grazing behavior, distribution and gainsHart, R. H.; Bissio, J.; Samuel, M. J.; Waggoner, J. W. (Society for Range Management, 1993-01-01)Reduced pasture size and distance to water may be responsible for the alleged benefits of intensive time-controlled rotation grazing systems. We compared cattle gains, activity, distance traveled, and forage utilization on a time-controlled rotation system with eight 24-ha pastures, on two 24-ha pastures grazed continuously (season-long), and on a 207-ha pasture grazed continuously, all stocked at the same rate. Utilization on the 207-ha pasture, but not on the 24-ha pastures, declined with distance from water. At distances greater than 3 km from water in the 207-ha pasture, utilization was significantly less than on adjacent 24-ha pastures, at distances of 1.0 to 1.6 km from water. Cows on the 207-ha pasture travelled farther (6.1 km/day) than cows on the 24-ha rotation pastures (4.2 km/day), which traveled farther than cows on the 24-ha continuously grazed pastures (3.2 km/day). Grazing system, range site, slope, and weather had minimal effects on cow activity patterns. Gains of cows and calves were less on the 207-ha pasture (0.24 and 0.77 kg/day, respectively) than on the 24-ha rotation pastures or 24-ha continuously grazed pastures (0.42 and 0.89 kg/da, respectively), with no differences between the latter. Calculated "hoof action" on the rotation pastures was less than that demonstrated to increase seed burial and seedling emergence. Intensive rotation grazing systems are unlikely to benefit animal performance unless they reduce pasture size and distance to water below previous levels, decreasing travel distance and increasing uniformity of grazing.