AFTER five years of rotational grazing one New York state milk producer believes his cows have harvested greater amounts of higher quality feed through grazing than he ever achieved by tractor and machine.
Lewis Shuttles 190-cow herd at the 170ha (420 acre) Lew-Lin Farm, Ithaca, New York state, started grazing his cows five years ago. Previously, cows only went out for exercise and were milked three-times-a-day, averaging 10,150 litres a cow.
"Feed and labour costs with confinement feeding were high. It was taking too much time and the payback wasnt there. So we divided some of the hay fields into 3.6-acre paddocks and seeded down some of the corn fields to cocksfoot grass and clover. In the first year we had 110 acres for grazing."
Cows averaged 8165 litres in first two years of rotational grazing, when milked twice-a-day. Feed costs were reduced by about 50% when the cows were grazing, and less labour was needed to care for the cows. Mr Shuttle also noted improvements in the cows feet.
Since then grazing management has been fine tuned, he explained. This has included installing water pipes to all paddocks which increased yields by about one litre a cow a day and giving cows fresh grass every 12 hours instead of every 24 hours. Yields are now 9270 litres a cow on twice-a-day milking and the herd still calves all year round.
"When there is too much grass in a paddock for 12 hours, we run a break wire through it, the wire then is moved at 11am or after the afternoon milking. Moving this wire is like sweeping feed up to cows in the barn, encouraging higher intakes and driving up milk yield," said Mr Shuttle.
Paddocks are rotated every 10-14 days in spring and every 14-21 days in summer depending on rainfall and grass growth. (Rotations are shorter than in the UK because grass growth peaks higher, but can also be very low during a drought because the summer temperatures are higher.)
Mr Shuttle aimed to keep grass between 20 and 25cm (8 and 10in) high for grazing, and a group of dry cows follows the cows to clean up any remaining grass. Cows can graze from the end of April until late October.
A mixed ration of shell corn, maize silage and protein concentrate is fed before cows go out to grass. In May and June when grass growth peaks, only 30-40% of the ration fed in winter is offered to cows. Ration ingredients remain almost in the same proportions as the winter diet.
When it is very hot cows come in to eat their mixed ration at 11am, before milking at 2pm, and stay in until after milking when it has cooled down.
Heifers are also grazed, going out to grass from eight months old until calving. They are supplemented with maize silage and hay in winter.
Mr Shuttle has also tried drilling perennial ryegrass seeds with clover, which makes a good high protein feed. He is now considering using more ryegrass in swards, but has found some varieties are not winter hardy enough and suffer from aggressive grazing.
Feed costs are reduced by 50% when cows are grazing, says Lewis Shuttle.