Farm Ireland

Saturday 18 November 2017

Avoiding damage to pasture is the key to surviving this awful deluge

Mary Kinston

After a slight increase in soil temperature in the middle of last month, I wrote about how hopeful I was that we had turned a corner.

I naively thought that just one good week would see the challenging times behind us. It certainly lifted farmers' moods and optimism was high, with growth rates of around 100kg DM/ha/day quite common.

It's now only seven weeks later and both cows and farmers are once again struggling, this time with deluges of rain and prolonged wet conditions. Combined with the falls in milk price, 2012 is certainly becoming an emotional, feed and financial roller coaster.

Most farmers are experiencing a free-fall of milk production per cow, loss of body condition score, poor grass quality, low pasture covers, yellowing pastures and poor grass growth rates. In places, this has been compounded by a bid throughout June to aid pasture quality by topping and pre-mowing a large amount of the grazing area, combined with short rotation lengths.

A number of farmers have resorted to supplementing the cows heavily and a common question has been how quickly can you feed silage after ensiling?

When pasture is ensiled, its sugars are converted into lactic acid by bacteria. It's the lactic acid that pickles the pasture and preserves it. Lower dry matter (wetter) silage actually ensiles quicker than high dry matter crops but has a greater risk of being low quality.

Also, crops with higher sugar content will also ensile quicker. Generally crops of 20pc DM take around 8-14 days and 30pc DM take 14-21 days, so generally two weeks is enough.

Another common question is whether there is any benefit, either immediate or long-term, by feeding concentrates in wet weather conditions.

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The impact of grass dry matter on cow intake varies depending on which piece of research you consider. A study in 1998 (Peyraud and Astigarrage) suggested that every 4pc fall in DM below a critical level of 18pc would reduce intake by 1kg of DM.

Another piece in 1992 (Van Vuuren) determined that a fall in DM from 22pc to 14pc reduced pasture intake from 16.8kgDM to 13.3kgDM/cow. Since 2009, anecdotal evidence would suggest that offering 1-2kg/cow in a period of prolonged (weeks rather than days) wet conditions may be beneficial for both cow intake and milk production.

If you are feeding concentrate, opt for a high energy ration and for cows in mid-lactation aim for a protein content of 16pc.


The key to surviving a wet spell is to avoid pasture damage. On-off grazing, where the cows spend a short period (3-4 hours) in a paddock, is very effective.

Taking cows in and out of different gateways will reduce the damage caused, and start grazing from the back of the paddock using spur roadways. Keep blocks as square as possible instead of strip grazing.

Higher pasture covers will provide better physical protection against poaching. The optimum is a cover of 12-15cm which is generally a pre-grazing cover of greater than 1,000kg DM/ha. If your pre-grazing covers are less than this, cows are likely to benefit from a forage supplement.

Longer rotations are also preferable, such as 22-28 days, but keep reviewing your situation to be ready to alter this to suit any change in grazing conditions.

Pasture utilisation will fall, as the crushing, bruising and burial of pasture in the mud will make it unpalatable and difficult to eat. Your feed wedge and feed budget will have to accommodate higher residuals and this will potentially reduce pasture quality in subsequent grazings.

Other management strategies to consider are the reduction of stock numbers to improve the feeding of the milking herd. Consider removing dry stock such as calves and bulls after 12 weeks of mating, identify culls and empties by scanning and milk recording, and remove these if the wet spell continues.

Give enough attention to other stock classes, especially weanlings, which will suffer, especially if they have nowhere dry to lie.

Review your financial position. Update your budget and cash-flow to determine how much money is available to spend on extra inputs with an aim to confine the financial damage to one year.

You may have to consider some corrective management. Lastly, go and check out your farming friends, neighbours and discussion groups, and talk about your challenges as tough conditions can make you feel very isolated when the likelihood is that you are all in the same boat together.

Dr Mary Kinston is a Kerry-based farm consultant. Email:

Indo Farming