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Independent.ie

Sunday 23 September 2018

Advice: This is not a year to be carrying any passengers on the milking platform

Mary Kinston

As I sit basking in the Kerry sunshine writing this column, I realise there are many of you wishing that this period of dry weather would end.

When you consider that some places haven't had rain for almost two months and that one tonne/ha of grass growth requires 20-25mm of rain we will need significant rainfall to avoid a crisis.

Here are some possible grazing/forage management options if the dry spell continues indefinitely.

Extend Rotation Length to 26-30 days

The first step in dry conditions, as soon as it is obvious that pasture growth rates are declining or for recovery, is to lengthen the rotation length from around 20 days (1/20th of the farm) to 30 days (1/30th) to reduce the amount of area grazed each day by the herd.

Lengthening the rotation to 30 days will reduce the amount of pasture eaten on a daily basis, which will lengthen the limited supply.

This will reduce the decline in the average pasture cover and allows each paddock more time for recovery and regrowth, especially once the rain is received.

While some paddocks may be unsightly with seed heads and stemmy pasture, resist the urge in this rotation to top or pre-mow prior to grazing as this will hinder grass growth and recovery until adequate rain has been received.

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Supplements - high energy and 16pc crude protein

In drought conditions, cows need high or increased levels of supplementation as grass growth declines.

While this is hard on feed bills, especially after having fed well over 500kg per cow during the wet spring, meal or concentrates should be your first option.

Pasture quality will also decline because it increases in fibre, so both pasture quantity and quality will limit intake and milk production.

However, to get high responses to supplement, it's imperative that the available pasture is eaten and not wasted.

Leaving poor grazing residuals (less than 4cm) will only reduce pasture quality further and this will rot away once rain is received.

Meal should be fed potentially up to 7kg before forage is introduced.

Your stocking rate and financial position need to be considered. Give due consideration to all other options before relying solely on purchased feed to fill the gap, especially if you are under pressure for winter feed. The use of winter feed reserves is the last resort.

When choosing a supplement, it needs to be primarily high-energy content and secondly 16pc crude protein to support mid-lactation.

If high levels of concentrate feeding are required, consider the use of a nut over a coarse mix, and provide the cows with ample water.

If your water system is under pressure, then provide water in the yards after milking to reduce the demand on the troughs in the paddock.

Consider removing and selling off all known culls as soon as possible.

If dry conditions are prolonged and continue throughout July, scanning to determine cows in-calf, culling empties and drying off high SCC or lame cows will be the next option. It's definitely not the year for carrying any passengers on a farm.

Fertilisers

In a dry summer, the biggest response to supplement and fertiliser is after the rain comes.

This is because there is pasture decay and it takes a while for pastures to recover and grass growth to increase.

A simple rule of thumb for now is: if it's green and growing go, if it's brown, dry and crunchy, no!

A number of farmers have questioned the use of nitrogen fertiliser in dry conditions.

While the application of nitrogen is important in summer to promote high-quality pasture, tillering and ryegrass persistence, it needs to be applied before the soil moisture is limiting grass growth.

Otherwise the plant won't get any of the available nutrients. If the farm is moisture-stressed there's no point applying fertiliser until after substantial rain of greater than 25mm has been received.

Once substantial rain has fallen, note that while there is a considerable pool of nitrogen already in the soil, responses to nitrogen fertiliser still occur.

Applying 30-40 units of nitrogen fertiliser after rain will give pasture plants immediate access to some N, while the soil processes recover with improved moisture levels. Continue to hold a grazing rotation of ideally 26-30 days once rain is received.

For those farms that have yet to feel a real impact of the dry conditions on grass growth, apply nitrogen (CAN rather than urea) before the soil moisture becomes limiting.

It helps the perennial ryegrass plant convert from producing seed heads to high-quality leaf, by promoting vegetative tiller growth.

Finally, while prolonged dry conditions may be hard to bear due to its impact on feed supply, realise that it is actually doing some good for soil structures.

Wet holes have finally dried up and where cracks are appearing, mother nature is helping the soil is doing its own drainage work.

Mary Kinston is a discussion group facilitator and consultant, and farms with her husband in Co Kerry

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