13 December 1996

Measuring grass cover key to extending season

Extending the grazing season into late autumn and early spring cuts milk production costs. But success depends on measuring grass cover every week. Jessica Buss reports

EXTENDING grazing until late December is cutting production costs for Co Kerry milk producers Noel and Lori Fitzgerald.

They started extending the grazing season three years ago on the 29ha (72 acres) of cow grazing at their 97ha (240-acre) farm at Killeny, Castlegory.

"Cows stay out until mid-December, we no longer feed autumn concentrates, and last year the fresh calvers went out from February 15 for a quick bite," explains Mr Fitzgerald. He calves 70% of his 80-cow herd – currently dry, as this years quota is filled – in February.

"When we first started trying to grow more grass we still paid for fertiliser and silage-making. Now we are gaining confidence and reducing our reliance on silage and fertiliser, restricting nitrogen when the grass is growing away," he says.

Each year 8-10t freshweight of silage has been made, but he estimates that 3-5t of silage should be sufficient now.

There are no silage fields but most paddocks are cut through the year. "We dont have set silage cutting dates, but harvest when the summer rotation speeds up and the extra grass is there," says Mr Fitzgerald. The key to managing extended grazing is measuring grass cover every week, he reckons. This helps to plan grazing by giving an estimate of daily grass growth. Mrs Fitzgerald expects that weekly plate meter measurements will give a good picture of daily grass growth in three years time.

In early November growth rate was 30-35kg DM/ ha a day. This growth was underestimated, so the grass cover on the farm is 2800kg/ha instead of 2200kg/ha, the target for the end of the grazing season. Currently cows are not grazing fast enough to reduce the cover to 2200kg/ha by December 20 and so youngstock will now come on to the cow grazing area.

Grazing consultant Paul Bird (right) suggests Neal and Lori Fitzgerald graze their dry cows until the average grass cover is 2200kg/ha, then stop.


&#8226 Good access needed.

&#8226 Measure grass cover frequently.

&#8226 Leave a wedge of grass cover.

&#8226 Stop grazing at an average cover of 2200kg/ha.