• Forage selection by cattle on fescue prairie in summer or winter

      Willms, W. D.; Rode, L. M. (Society for Range Management, 1998-09-01)
      The rough fescue grasslands are important for livestock grazing as well as other values such as wildlife habitat, recreational opportunities, and watershed properties. The impact of livestock on these grasslands must be better understood in order to manage grazing for optimal use of the resource. A study was conducted from 1992 to 1994 on the rough fescue grassland near Stavely, Alberta, to determine forage selection by cattle in the winter and summer and the effect of canola supplementation on forage selection. Twelve 1.7-ha paddocks were stocked with 2 cows (Hereford) at 3.2 animal-units-months ha-1 in winter; canola supplements (0.0, 0.4, 0.8, and 1.2 kg animal-1 day-1) were applied in a randomized complete block design. Three additional 1.7-ha paddocks were similarly stocked but grazed in the summer with out canola supplements. Forage availability, utilization, and relative preference were estimated for 4 major plant species. In both winter and summer, rough fescue (Festuca campestris Rydb.) was utilized most (P < 0.05) and Idaho fescue (Festuca idahoensis Elmer) and smooth aster (Aster laevis L.) were utilized the least. Of total forage utilized, rough fescue and Parry oat grass (Danthonia parryi Scribn.) contributed about 90 and 9%, respectively, in winter and about 62 and 32%, respectively, in summer. In summer, Parry oat grass was utilized in proportion to its availability. Rough fescue was the preferred species in both winter and summer. Percent forage utilization in winter was not affected by supplementation with canola. The high preference for rough fescue appeared to be determined by the accessibility of the large tufted plants to cattle. This was particularly evident in winter when access to plants was impaired by snow cover. Successful winter grazing on these grasslands is enhanced with a large proportion of rough fescue plants in the stand.
    • Pine needle consumption by cattle during winter in South Dakota

      Pfister, J. A.; Panter, K. E.; Gardner, D. R. (Society for Range Management, 1998-09-01)
      Pregnant cattle that consume ponderosa pine (Pinus ponderosa (Lawson) needles often abort. The objectives of these studies were to: 1) determine needle consumption by grazing cattle; 2) relate consumption in pen-fed and grazing cattle to weather variables; and 3) determine if needle temperature influenced consumption in pen-fed cattle. Trial 1 was conducted from 3 Dec. 1991 to 12 Feb. 1992 near Custer, S. Dak. Eight mature cows grazed a 9-ha pasture. Needle consumption was measured using bite counts H. and fecal analysis. The winter was mild, and cattle consumed few needles (< 2% of bites). Trial 2 was conducted in the same location from 5 January to 2 March 1993, using 6 pregnant cows kept in pens and 5 open cows grazing the pasture. The pen-fed cows were offered 1 kg of fresh pine needles daily; methods for grazing cattle were the same as in the previous trial. Further, the pen-fed cows were offered warm or cold green needles in 2 acceptability trials. Grazing cattle consumed an average of 20% of bites as pine needles. As snow depth increased, pine needle consumption increased, particularly from short (< 2 m tall) tree (P < 0.01). The percent of bites of green needles was related (r2 = 0.69) to minimum temperature and snow depth, with greater consumption at colder temperatures and at deeper snow depths. As snow depth increased, cattle reduced daily grazing time (P < 0.01); at colder temperatures, cattle also reduced grazing time (P < 0.05). Pen-fed cows ate 483 g pine needles/day (fresh weight), with no abortions occurring. Cattle preferred cold needles to warm needles (P < 0.05) in January, despite tree size; whereas, the opposite result was noted in February. We conclude that snow depth, reduced amounts of grazable forage, and cold ambient temperatures are crucial factors in consumption of ponderosa pine needles by grazing cattle.
    • Seasonal preferences of steers for prominent northern Great Basin grasses

      Cruz, R.; Ganskopp, D. (Society for Range Management, 1998-09-01)
      The objective of this research was to determine, on a seasonal basis, the relative preferences of cattle for 7 native grasses and d crested wheatgrass (Agropyron desertorum (Fischer ex Link)Schultes), a long-used introduction in the Pacific Northwest. Methods involved observing forage selection processes of 3 steers in paddocks, where plants existed in equal densities and in rangeland pastures with variable forage composition. Design of paddock and pasture studies was a randomized-complete-block with 3 replications, 3 stages of phenology (vegetative, anthesis, and quiescent), and 8-11 forages. Dietary proportions as indexed by bite-counts changed (P < 0.01) with phenology and varied among species. Diets were more similar (P < 0.05) than forage composition between the 2 study areas (paddocks and native pastures), and became less similar (p < 0.05) as phenology of the grasses advanced from vegetative growth through anthesis and quiescence. Steers were selective grazers during vegetative and anthesis stages of phenology, and despite variations in herbage availability, 'Nordan' crested wheatgrass was the most prominent dietary component in paddocks and pastures. Variation in proportions of grasses in the diet was associated (P < 0.05) with measures of available forage in the paddocks (r = 0.46-0.89, average = 0.72) but poorly associated with herbage composition in pastures (r = 0.41-0.02, average = 0.12). Inconsistencies in rankings of relative preference indices and dietary proportions of grasses suggested that measures of herbage availability may confound the predictive utility of relative preference indices. More grasses were acceptable to cattle at quiescence, with crested wheatgrass ranging from 8-26% of the diet. We suggest that with proper management, interseedings of crested wheatgrass on native range may be used to lessen grazing demands previously borne by native perennials early in the grazing season.