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David Davis
21262 Genoa Road
Linneus, MO 64653
Phone: 660 895-5121
FAX: 660 895=5122
Email: DavisDK@missouri.edu

Forage Availability

No quadrats were clipped on any treatments in 2000 and all forage availability estimates for the final year were predicted from the height:yield equations in Table 5. Because of the low accuracy of the equations for bulk yield in continuously grazed pastures, only green forage dry matter yield is presented for 2000 (Figures 10, 11, 12,& 13). From June through September, rotational grazing resulted in significantly more green forage available/acre at all stocking rates compared to continuous grazing. Accumulated dead material in continuously grazed pastures resulting from uncontrolled growth during spring reduced the percentage of green forage available. It is difficult to explain the lack of animal response to rotational grazing management in this study in light of such prominent differences in forage availability and potential quality.

Figure 10. Green forage dry matter yield in 2000 by month for continuously and rotationally grazed pastures at 300 lb liveweight/acre stocking rate.

Figure 11. Green forage dry matter yield in 2000 by month for continuously and rotationally grazed pastures at 600 lb liveweight/acre stocking rate.

Figure 12. Green forage dry matter yield in 2000 by month for continuously and rotationally grazed pastures at 900 lb liveweight/acre stocking rate.

Figure 13. Green forage dry matter yield in 2000 by month for continuously and rotationally grazed pastures at 1200 lb liveweight/acre stocking rate.

Over the five-year course of the study, rotational grazing consistently maintained a higher level of green forage availability at every stocking rate. At the lowest stocking rate, bulk herbage mass tended to be slightly higher for continuously grazed pastures compared to rotational grazing, while green forage dry matter yield was significantly greater for rotational grazing (Figures 14 & 15). At both 600 and 900 lb liveweight/acre stocking rates, bulk herbage mass were similar for continuous and rotational grazing while green forage yield was significantly greater for rotational grazing (Figures 16, 17, 18, & 19). At 1200 lb liveweight/acre stocking rate, bulk herbage mass was greater late in the season for rotational grazing and green forage dry matter yield was significantly greater for rotational grazing throughout most of the grazing season (Figures 20 & 21).

Figure 14. Five-year mean bulk forage yield for continuously and rotationally grazed pastures at 300 lb liveweight/acre stocking rate.

Figure 15. Five-year mean green forage yield for continuously and rotationally grazed pastures at 300 lb liveweight/acre stocking rate.

Figure 16. Five-year mean bulk forage yield for continuously and rotationally grazed pastures at 600 lb liveweight/acre stocking rate.

Figure 17. Five-year mean green forage yield for continuously and rotationally grazed pastures at 600 lb liveweight/acre stocking rate.

Figure 18. Five-year mean bulk forage yield for continuously and rotationally grazed pastures at 900 lb liveweight/acre stocking rate.

Figure 19. Five-year mean green forage yield for continuously and rotationally grazed pastures at 900 lb liveweight/acre stocking rate.

Figure 20. Five-year mean bulk forage yield for continuously and rotationally grazed pastures at 1200 lb liveweight/acre stocking rate.

Figure 14. Five-year mean bulk green yield for continuously and rotationally grazed pastures at 1200 lb liveweight/acre stocking rate.

Green forage yield is a much greater determinant of voluntary forage intake by grazing animals than is total herbage mass. Low stocking rates tend to result in significantly higher percentage of dead material in the sward. At all stocking rates, continuously grazed pastures tended to have more dead material present in the sward early and late in the grazing season while levels were similar between continuous and rotational grazing in the middle part of the grazing season (Figures 22, 23, 24, & 25). The corresponding pattern of higher yield of green forage early and late in the grazing season for rotationally grazed pastures and similar levels at midseason was apparent in the preceding figures illustrating forage yield. 

Figure 22. Four-year mean percent dead material in sward of continuously and rotationally grazed pastures at 300 lb liveweight/acre stocking rate.

Figure 23. Four-year mean percent dead material in sward of continuously and rotationally grazed pastures at 600 lb liveweight/acre stocking rate.

Figure 24. Four-year mean percent dead material in sward of continuously and rotationally grazed pastures at 900 lb liveweight/acre stocking rate.

Figure 25. Four-year mean percent dead material in sward of continuously and rotationally grazed pastures at 1200 lb liveweight/acre stocking rate.

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