Evaluation of an herbage-based method for adjusting short duration grazing periods
1990
Mosley, J.C. | Dahl, B.E.
Livestock nutrition and performance under short duration grazing (SDG) possibly could be enhanced by incorporating flexible grazing periods (i.e., varying the number of days a pasture is grazed without interruption). This study evaluated a method that used available herbage as an indicator for adjusting length of grazing periods for SDG on rangeland. A controlled grazing trial was conducted using four simulated six-pasture SDG systems on sand shinnery oak (Quercus havardii) rangeland on the Rolling Plains of Texas. There were four grazing cycles during the five-month grazing season. Each system was variably stocked with four tester steers and up to five additional grazer steers. Steers in two of the systems were rotated between pastures according to a fixed, seven-day grazing period (control). Steers grazing the remaining two systems were rotated independently according to available herbage (flexible rotation). Available herbage was determined at the beginning of each pasture's grazing period by clipping current annual herbaceous growth within 0.4-m2 (4.8-ft2) quadrats. Grazing periods for flexible rotations varied from 0-14 days. Herbage crude protein, herbage digestibility, herbage moisture content, available herbage, and animal gain were not improved (P > 0.10) by rotating steers flexibly according to available herbage when compared to rotating steers every seven days. Therefore, our technique using available herbage to adjust grazing periods for SDG was not advantageous under conditions of this study.
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