The objective of this study was to test the combined effect of offstream water and trace mineral salt on cattle distribution in a riparian meadow and its adjacent uplands. From July 15 to August 26, 1996 and 1997, three treatments were each randomly assigned to one pasture in each of three blocks. Sixty cow/calf pairs were then randomly allotted to the grazed pastures. The treatments included 1) stream access and access to offstream water and trace-mineral salt (off-stream), 2) stream access and no access to offstream water or trace-mineral salt (no-offstream), and 3) ungrazed control. The response of cattle was measured through visual observations of cattle distribution, grazing activity and travel distance, cow/calf performance, and fecal deposit distribution. Distribution patterns of the cattle, measured as the distance of cattle from the stream, was characterized by a time of day x treatment x time in grazing period x year interaction (P < 0.05). No-offstream cattle began the day further from the stream than offstream cattle but consistently moved closer to the stream after the morning grazing period (0600 to 0900). Differences in distribution patterns between the two treatments were more pronounced early in the grazing period than late in the grazing period. Grazing activity, fecal deposit distribution, and travel distance of cattle were not affected by the presence of offstream water and trace-mineral salt. Cows and calves with offstream water and trace-mineral salt gained 11.5 kg and 0.14 kg/d more, respectively, than no-offstream cows and calves averaged across years (P < 0.05). Overall, cattle distribution patterns and cow/calf performance were influenced by the presence of offstream water and trace-mineral salt. Changes in distribution were most pronounced early in the grazing season.

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Two digestion trials, using 20 ram lambs (Experiment 1) and 8 cows (Experiment 2) provided ad libitum access to mature prairie grass hay, were conducted to evaluate controlled release intraruminal chromic oxide boluses and alkaline hydrogen peroxide lignin as markers for estimating forage intake by the fecal output/indigestibility ratio. A soybean meal and 3 urea based supplements were fed to lambs in Experiment 1. For both experiments, daily fecal output was weighed and sampled for 6 days (Experiment 1) and 5 days (Experiment 2) beginning 7 days after oral administration of CrzOJ controlled release boluses. Rectal fecal grab samples were also collected at 1000 daily and at 4-hour intervals on day 4 of collections for Experiment 2. For both experiments CrzO, excretion rates based on total collections were used to evaluate CrzO, controlled release boluses and alkaline hydrogen peroxide lignin predictive value in place of manufacturer's stated release rate. In experiment 1, fecal CrzOJ output was 224 mglday + 3.9 compared to the manufacturer's stated release rate of 201 mg CqOJlday. Fecal alkaline hydrogen peroxide lignin recovery was 97.8% + 1.9. Samples composited over the 6-day collection period predicted fecal output, apparent dry matter digestibility, and dry matter intake similar (p = 44, .15 and 55; respectively) to actual values. Supplemental treatment and dry matter intake had no effect (P 1 .38) on daily fecal Crz03 output or alkaline hydrogen peroxide lignin recovery. In Experiment 2, fecal Crz03 was 1,662 mg/day + 63 compared to the manufacturer's stated release rate of 1,505 mg CrzOl/day. Fecal alkaline hydrogen peroxide lignin recovery was 95.9 % + 7. Using 5-day composited samples, predicted fecal output, dry matter digestibility, and dry matter intake were similar (p = .49, .21 and .49; respectively) to actual values. Increasing the number of daily grab samples increased R2 values between actual and predicted fecal output and dry matter digestibility. Fecal grab samples and total fecal collection samples provided a similar relationship (R'=.71) between actual and predicted dry matter intake when each were composited over 5 days. Time of day did not affect fecal Cr203 or alkaline hydrogen peroxide lignin concentrations. These results suggest that grab samples collected Published with the approval of the Director of the South Dakota Agr. Exp. Sta. as Publ. No. 2631 of the Journal Series. Manuscript received 1 Sept. 93. 418 once daily on 5 consecutive days can be used to predict fecal output when Cr,O, controlled release boluses are used. Although recoveries of fecal alkaline hydrogen peroxide lignhr were near 100% in these experiments, digestibility estimates using this internal marker were variable and adversely influenced predictions of dry matter intake.

To quantify the effects of season of use on beef cattle distribution relative to the riparian area, 52 cow/calf pairs were used to evaluate 1) early summer grazing (mid-June to mid-July), and 2) late summer grazing (mid-August to mid-September) during the summers of 1998 and 1999. Within a block, cow/calf pairs used during early summer were also used during late summer grazing periods. Pastures were stocked to achieve 50% utilization of herbaceous vegetation after a 28-day grazing trial. Livestock location and ambient air temperature were recorded hourly during two, 4-day periods in each season of use. Locations were transcribed to a geographical information system for the study area. Ocular vegetation utilization estimates, forage quality, and fecal deposits within 1-m of the stream were recorded post-grazing. During early summer, cattle were further from the stream (P < 0.01) than late summer, averaging 161 and 99-m, respectively. Cows were observed closer (P < 0.01) to the stream when ambient air temperatures were higher. Fecal deposits within 1-m of the stream were similar (P = 0.13) following early and late summer grazing. Forage quality varied (P < 0.01) between seasons, with early summer forages having lower dry matter, greater crude protein, lower fiber, and greater in situ dry matter disappearance compared with late summer forages. Utilization of riparian vegetation was lower and use of upland vegetation greater during early summer than late summer (P < 0.05). In summary, season of use affected cattle distribution relative to the riparian area, with late summer pastures having more concentrated use of riparian vegetation.

Livestock grazing in riparian areas is an important management issue on both private and public lands. A study was initiated in northeastern Oregon to evaluate the economic and ecological impacts of different cattle management practices on riparian areas. The effect of off-stream water and salt on livestock distribution and subsequent impact on riparian use, water quality, and livestock production was evaluated. A multi-period bioeconomic linear programming model is used to evaluate the long-term economic feasibility of this management practice with a riparian utilization restriction of 35% for a 300 cow-calf operation. The utilization restriction resulted in economically optimal herd sizes 10% smaller than the baseline herd size. With the management practice, cattle were distributed more evenly, consumed more upland forage before maximum riparian utilization was reached, and gained more weight. The economic impacts of these outcomes were increased with expected annual net returns to the ranch for the project ranging between $4,500 and $11,000 depending on cattle prices and precipitation levels.