Dairy NZ

In cases of flooding pasture will fall into one of four groups:

• Flooded and silted but little or no ponding. 
• • Pasture is green and growing but with some contamination
  • Pre-graze top if weather is suitable 
  • Provides increased intake, increased bite rate, possibly more time for cows to lie down - important in stressed cows, especially with soft or tender feet 
  • Get rid of rubbish grass and sets paddock up for re-growth next rotation
• Pasture brown and dying but dry grass predominates
• • Some green, some rotting ie roots may still be alive 
  • In winter pasture is likely to survive submersion for long periods - up to 2 weeks even 
  •  Graze as above
  • This is low energy grass that needs compensation but is still useful for bulk dry matter and fibre
• Predominantly slimy rotting grass, plant is dying. 
• • Don't graze as this is poor feed quality and can depress rumen function
  • No real effective fibre
• Buried in silt
• • no use what so ever.

If ash cover is your issue:

• Physical presence of ash will decrease palatability and blown dust many cause respiratory problems.  Grass will grow through 15mm of ash
• Pasture will have a strong smell due to sulphur dioxide.  This will increase acidity of pasture
• Ash in water will increase acidity and occasionally will be toxic if fluoride concentrations are high.  More of a problem in puddles but also water troughs.