Mild weather helps grass growth rates (no surplus’ yet though)

The mild weather has kept grass growth rates above demand, but there are no surplus’ on most farms as yet.

There are a few farms with cover/LU now over 200kg which is heading towards a surplus.

However, the change in weather towards the end of this week is likely to set growth rates back somewhat.

Advice

Once you have completed a grass walk, check the growth rates for your farm and look at the forecast, then estimate what growth will be for the coming week.

Example

A farm stocked at 4LU/ha, with a demand of 68 (17kg/LU), a growth rate of 40 and an average farm cover (AFC) of 840, the cover/LU will be 210kg.

If we estimate that growth rate will drop to 40kg for the coming week, owing to lower air temperatures, we can subtract the growth rate from our demand to calculate what change in AFC this would equate to.

Going on the example above, then 28kg more grass will be consumed/ha/day than we are growing. Over one week, we would be eating into our farm cover by 196kg (7 days x 28kg).

This would result in cover/LU dropping to 160kg by next week. Therefore, while a cover/LU above 180kg is considered high, if growth rates drop, this cover will be required.

The grass demand and severity of the weather change will dictate how much ‘extra’ grass must be kept on the platform.

If growth rates were to continue as is, target cover/LU should be between 160-180kg.

Non- quota era

With quotas now gone, there will have to be a disciplined approach to grass management to maintain milk solids output and maximise conception rates.

Chasing milk yield and leaving a residual of 300kg in the paddock will undoubtedly increase performance in the short term, but the long term effects of high residuals are extremely costly as we reduce grass utilisation, energy content and digestibility in the subsequent rotations.

We must be efficient – allocate grass correctly based on how much the herd is eating per day now that they are peaking intake. In expanding or expanded herds, it is difficult to judge by eye what size of break cows require owing to a huge difference in demand from previous years.

While we have to ensure cows are supplemented with magnesium (30-40g/day), feeding extra meal to drive output will simply increase our cost base.

Grass quality on well managed farms will be 12ME, or 1.0UFL. The majority of concentrates are higher in energy on a dry matter basis, but not on a fresh weight basis.

That is, grass is 1.0UFL, whereas a lot of meal rations will be closer to 0.95, therefore lower in energy. By increasing meal therefore, we are having a direct substitution effect.

In a high yielding herd where cows peak intakes are greater than 18kg DM, meal supplementation may be necessary to meet intake requirements.

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