You can’t manage what you don’t measure

During the Irish Grassland Association (IGA) dairy conference, on Wednesday, January 6, Dr. Deirdre Hennessy, a Teagasc grassland research officer based in Moorepark, Fermoy, Co. Cork, spoke about grass measuring as a tool to off-set the requirement to reduce nitrogen (N) usage on farms by 20%.

Dr. Hennessy said: ”Along with incorporating white clover into swards, measuring grass to budget for the short term can allow you to predict surpluses and deficits, rather than feeding concentrates once a shortage has already occurred.

”Using a system to record the data is the most efficient way to manage grass. Grass measuring will allow you target paddocks that require fertiliser, based off growth rates.”

Also Read: Establishing white clover in grass swards

Methods of Measuring Grass

You can’t manage what you don’t measure! Grazed grass is the cheapest animal feed available to Irish farmers. In order to manage it successfully, it needs to be measured – this should help to improve farm profitability.

Grass can be measured in kg DM/ha (dry matter per hectare) or in cm. According to Teagasc, every 1cm has approximately 250kg DM/ha for cattle farms or 350kg DM/ha for sheep farms (mixed cattle and sheep farms are around 300kg DM/ha).

Teagasc uses 4cm residuals when estimating grass covers as that is the height animals should graze to, so if the sward height on a cattle farm is 10cm then 10-4 = 6cm or 1,500kg DM/ha which should be grazed.

The main points when measuring are to get a good representation of the paddock’s grass cover and measure at least once per week during the grass growing season.