20 November 1998

ROTATIONAL GRAZING FORMULA PAYS OFF

HIGH quality grass, and plenty of it, is available for extended grazing on one Hants farm. Care is needed to avoid carrying too much grass over winter for quality spring grazing.

Martin Bazeley hosted his local BGS discussion group at Hipley Barn Farm, Southwick, where he started rotational grazing and back fencing just one year ago.

The 210-cow herd had 127ha (314 acres) available for grazing, but the systems success means this area has recently been reduced by 24ha (60 acres) for reseeding and cereal cropping.

Managing grazing to ensure drier paddocks have enough cover for an early turnout, but avoiding excessive grass cover being carried on any field over winter, is the challenge now facing Mr Bazeley.

"Milkers are grazing in two groups, 90 fresh calvers less than five weeks calved and 68 late lactation cows. Stale cows graze paddocks after fresh calvers, then dry cows follow stales to clean out paddocks."

Late lactation cows are still grazing day and night without concentrates, said Mr Bazeley. Fresh calvers are supplemented with 3kg maize gluten, 1kg soya and 4-5kg DM silage. Concentrates can only be trough-fed with forage.

"Calved cows came in at night on Sept 10, but since then it has rained and grass growth has been phenomenal," he said.

Fertiliser has been reduced with a single summer application in mid-July. Mr Bazeley applied a dressing in late September to some grazing paddocks to encourage growth.

BGS grazing consultant Paul Bird estimated Hipley Barn Farms average cover at 2200-2300kg DM/ha, ideal for extended grazing. But cover must be reduced to 2000kg DM/ha by the end of October, with no paddock having a cover above 2500kg DM/ha. High cover results in more mature grass producing dead material in the sward and poorer grass for early spring grazing.

Mr Bird calculated cows are eating an average of 11kgDM of grass. This is about half their total DM intake because some are dry, while fresh calvers are receiving some silage. They are stocked at 2.8 cows/ha (1.1/acre) and so remove 30kg DM/ha of grass a day. This means at a grass growth rate of 30kg DM/ha average farm cover would be maintained.

To ensure covers would reduce and decide whether applying more fertiliser was wise, Mr Bird suggested calculating a more detailed grazing budget, estimating grazing days possible in each field over the next six weeks, allowing for some grass growth.

Martin Bazeley: Now convinced that extended rotational grazing works.