8 October 1999

Ascientific approach to cow grazing

TAKING a more scientific approach to grazing will allow Irish producers to make more of grass in cow diets.

This means having enough quality grass, said Cork-based Teagasc dairy adviser Ger McMahon at the Irish Ploughing Championships.

"Producers should calculate grass budgets and walk their farms. By walking your land you can see whats coming ahead in terms of grass cover, because growth rates vary during the season."

He wasnt, however, advocating a grass only feeding policy, as this simply didnt work in Ireland. A flexible approach to feeding is required.

"When it becomes wet, dont be afraid to supplement cows diets with concentrates sooner rather than later."

Wet weather – which the Irish have suffered during the last month – means dry matters in grass fall and utilisation becomes poor. "You need to allocate larger grass areas to cows when this is the case, and offer a higher dry matter forage alternative as well."

He said there were some useful grass management targets for producers to use this autumn.

To ensure a full grazing season from mid-February to mid-November next year, aim to have an average grass cover of 400kg/DM/ha (measurement taken above 6 cm sward height) by the time of closing paddocks in late November, advised Mr McMahon.

"Dont be tempted to graze too late in to winter as this will reduce early spring growth," he warned.

Begin your last rotation on 8-10 Nov. Fields closed first will be the first grazed in the spring. But ensure grass covers taken in to winter are less than 2000kg DM/ha – covers above this increase winter kill leaving bare patches in grass, he said.

"A good target is to have the grass cover in your best paddock at 800-900kg/DM/ha, which should leave your average about 400 kg/DM/ha."