Will current rotational grazing management recommendations suit future intensive pastoral systems?

Authors

  • Danny Donaghy Massey University
  • Racheal Bryant Lincoln University
  • Lydia Cranston Massey University
  • Michael Egan Teagasc
  • Wendy Griffiths DairyNZ
  • Jane Kay DairyNZ
  • Keith Pembleton University of Southern Queensland
  • Katherine Tozer AgResearch

DOI:

https://doi.org/10.33584/rps.17.2021.3464

Keywords:

diverse pastures, grazing principles, grazing rotation, leaf regrowth stage, post-grazing residual

Abstract

This review aimed to determine whether current grazing management practices will suit future intensive rotationally grazed pastoral systems. A review of literature on grazing management recommendations found that there was good agreement on the ‘principles’ required for optimal grazing management. While these management practices have stood the test of time, it is concluded that shifts in external pressures (e.g., climate, plant selection and breeding, system intensification) compared to the period when farm-level grazing recommendations were first developed, may necessitate a rethink of current grazing recommendations. Examples include greater pasture masses (e.g., around 4000 kg dry matter (DM)/ha vs. the recommended range of 2600 to 3200 kg DM/ha) where short-rotation (annual, biennial) and tetraploid ryegrasses are sown, provided a consistent post-grazing residual can be maintained (possibly between 40- and 70- mm height). Milder winters and the use of ryegrass cultivars with higher growth rates in late winter/early spring may necessitate either lower target pasture covers at calving or shorter rotation lengths during winter. Longer grazing rotations (well beyond the 3-leaf stage, i.e., equivalent to deferred grazing) can be recommended for select paddocks from mid-spring into summer, to increase seasonal resilience across the farm. Longer residuals (even up to 70 mm - i.e., almost double the recommended height) might improve plant survival during periods of high stress (e.g., heatwaves, droughts). Lastly, diverse species pastures may require specific management to suit dominant species other than perennial ryegrass.

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Published

2021-09-17

Issue

Section

Resilient Pastures Symposium 2021