26 April 1996

Spring management vital to harvest highest profits

Management of grass in spring is critical. In the first of a series of articles NZ consultant Mark Blackwell discusses what is needed. Spring grass is also the subject of the first report from the Irish Grassland Associations 50th anniversary conference, held in Limerick last week.

WHAT is happening to pasture in spring? Management at this time is critical to maximising profit. It is a balancing act with good observation and sound judgement the keys.

As soil temperatures rise, and days get longer, pasture growth increases. It is now limited by grazing management rather than the cold. The most important decision a producer makes is the choice of stocking rates relative to the farms carrying capacity. In the UK this is modified by how many hours a day cows are out on grass. This time spent grazing limits dry matter intakes from pasture.

Concentrates feeding will also reduce pasture consumption. Both these factors determine a cows feed demand (dry matter a hectare a day). Management revolves around how much pasture there is on the farm, how frequently it is grazed and what grazing residuals are left after grazing.

Pasture damage by cows when grazing in wet conditions can reduce spring growth and must be avoided. One critical skill to learn is pasture assessment. In New Zealand pasture is expressed in terms of DM/ha. In reality producers usually make an estimate of pasture by eye appraisal and seldom with the aid of a rising plate meter.

For best results it pays to pursue certain pasture targets, such as the amount of on-farm feed cover and the speed of rotation at critical times. Targets will depend on the individual farm.

Aim for a minimum and maximum amount of pasture cover on the farm leading into the period of most rapid growth.

A minimum is required to have sufficient leaf area in the pasture to efficiently capture sunlight. We also need a certain amount of feed to provide a high proportion of the cows daily feed directly from pasture. A surplus is also needed on the farm so silage can be taken while not depriving cows of pasture in the process. Aim to harvest grass that is over 90% leaf.

A maximum target is needed to avoid pasture waste by leaving too much behind after grazing and losing it through decay. &#42

NZ consultant Mark Blackwell says management of pasture at this time is critical to profit.