Nutritional Impacts of the Wet Weather

September 8, 2017

Nutritional Impacts of the Wet Weather

As we navigate another period of wet weather, there are some key points which we must keep in mind as we head into the new season. When grass gets covered in soil and dirt it leaves deposits of Ash and specific metals which can cause problems. Any pastures that have flooded or had lying water, need to be aware of the following:

Mineral Lock Up:
  • High Iron – binds copper making it unavailable to the cow, may effect production, will reduce conception rates.
  • High Sulphur – as above when it links with molybdenum.
    • Promotes organic sources to improve bioavailability.
  • High Potassium – binds magnesium causing staggers.
  • High Aluminium – binds phosphorus which may effect production and fertility.
Forage Quality (this will be a key one):
  • Clostridia gets into the silage through soil and dirt contamination.
  • This will increase nutrient and dry matter losses.
  • Protein and digestibility will be reduced.
  • Can only be stopped by reducing pH as quickly as possible i.e. front end fermentation.
Early Lactation Performance:
  • This happened last spring, the wet weather reduced pasture intakes, farmers will not argue with this.
  • 15kg pasture dry matter intake at 20% DM = 75kg fresh weight = will be achieved.
  • 15kg pasture dry matter intake at 12% DM = 125kg fresh weight = not going to happen!
  • If intakes drop, energy drops, that effects milk production and fertility.
  • All they can do about it is either feed more higher DM forage (maize silage) or increase energy density = rumen protected fat.
  • Lower dry matters means lower water intakes and therefore lower mineral inclusions when applied through the water, keep a check of this.

This could all have serious effects on performance for the coming season so please discuss these risks with your clients, to summarise:

  • Consider mineral availability, organic sources may be needed due to high heavy metals and antagonisms (mineral bind).
  • Consider forage quality, clostridia will be high, fast pH drop is the only answer.
  • Consider energy in early lactation, be realistic about pasture intakes.
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About the Author

Nadine Olsen
Ruminant and Forage Technical Services Manager
BSc, MSc(Hons), BMS(Hons) Nadine is a Board Member and Vice Chairperson for New Zealand Young Farmers. Her Master’s Thesis examined genetic and nutritional factors affecting Read More

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Beef, Dairy, Deer, Forage