Timing the end of grazing

13 October 2000

Timing the end of grazing

By Marianne Curtis

LEAVING enough grass to ensure rapid spring re-growth must be the priority of dairy producers as autumn wears on.

How long grazing can continue is dependent on how much grass remains in paddocks, says MDC grazing consultant Carol Gibson. "At this time of year, once paddocks have been grazed, they shouldnt be grazed again before turnout."

Producers who have built cover up to 2600kg DM/ha in preparation for autumn grazing will need to slow grazing rounds to ensure pastures are grazed sufficiently, she says.

"Cows will be going into long grass which needs to be grazed down to 1700kg DM/ha, so aim for a grazing rotation of 40-60 days."

At housing, average pasture cover across the farm should be 1800-2000kg DM/ha. "Spring grazing takes priority when pasture cover is at this level. If grass is grazed too short, it will fail to grow in spring," says Miss Gibson.

But continuing to apply nitrogen until late October will assist spring growth. "Soil temperatures are still warm enough for nitrogen applications to be effective. Apply 25kg/ha as cows finish grazing each paddock."

Allocating cows with sufficient grass for a 24-hour period only, will minimise poaching damage, she says. "Back-fencing is essential otherwise spring grass growth will be compromised and poaching risk will increase."

However, minimal poaching is acceptable and slight surface muddiness shouldnt cause concern, she adds. "Keep cows out only while they are grazing; if they finish grazing after three hours then bring them in."

Spring calvers should be able to cope without supplementation but a close eye must be kept on condition score. "Cows which have worked hard over the grazing season can be on the light side. Aim to dry off any animal under condition score two either now or in the near future.

"Also, when production drops below 10-11 litres a day, consider once a day milking which saves time and improves condition score," advises Miss Gibson.

For autumn calvers in early lactation, building high levels of cover for autumn grazing is less critical than for spring calvers. "Aim for an average cover of 2300kg across the farm. Cows should be able to produce 15-18 litres of milk from autumn grass, with the remainder coming from concentrate supplementation."

Many autumn calving herds should aim to house by the end of October to prepare cows for service, she suggests. &#42

AUTUMNGRAZING

&#8226 Leave enough grass for spring growth.

&#8226 Apply nitrogen until late October.

&#8226 Back-fence to avoid poaching.