Grass grazed down to the ground

Is this too low to make cows eat down to?

I was told off by Aussie grazing guru Frank Tyndall when we met on a dairy farm in Kent recently – for extolling the virtues of the New Zealand system which ‘forces’ dairy cows to graze down to the ground before moving to the next paddock.

He believes that grazing this hard is detrimental to both grass growth and cow performance.

While many UK farmers have successfully adopted NZ ways, Frank thinks there is a middle, less extreme path that would produce more milk from grazed grass.

He suggests that lack of access to ‘cheap’ cereals and years of low milk prices drove the Kiwis to produce as much milk from grass, with a primary focus on production per hectare rather than production per cow.

Don’t ignore cow efficiency

Frank urges farmers not to ignore cow performance. More grass in the diet usually lowers the average feed cost, yes – but it often lowers milk yield per cow and hence cow efficiency.

Grazing too short also slows growth and reduces the amount of grass that will actually grow in future – with a great danger of exhausting the individual plants.

And we shouldn’t get hooked up on utilisation. 90% utilisation of an 8 tonne crop gives 7.2 tonne consumed; 70% utilisation of a 12 tonne crop (produced by allowing a longer rest period between grazings) means 8.4 tonnes has been eaten.

Grazing too short also restricts intakes – there is just not enough material for the cows to get a good biteful. 70% utilisation is more likely to sustain 8,000 litres per cow – 90% utilisation only 6,000 litres a cow.

Grass has to be wasted to some extent if high cow efficiency is to be achieved. If residue builds up, mow it. Not wasting any grass means farmers are probably wasting the potential within the cow.

Frank also disputes the usefulness of measuring swards and grazing wedges – saying this historical information is not helpful in planning the rotation ahead…

but we’ll leave that for another post!

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