Dairy special: Can early turnout help ease forage shortages and improve grass usage?

Benefits of early grazing

MR Van Barneveld says turning cows out early will deliver several notable benefits to the herd:

• Up to one tonne dry matter per hectare (0.4t/acre) can be gained in grass growth during the course of the year if cows are turned out in February as the grazing encourages grass growth
• If grass is left too long before grazing it will tiller higher up the stem, thus reducing its leafy content. Ideally grass should be grazed down to 4cm
• If grazing begins later, grass covers are likely to exceed 3,000kg/hectare (1,214kg/acre) and a higher density of cows is needed to graze it off, which increases risk of soil damage and reduces usage

GRAZING PLANNING

FARMERS should start planning ahead for spring grazing rotation in autumn, Mr Van Barneveld says.

He advises farmers to consider the following:

--- It is important to graze covers down to the optimum height in autumn in preparation for spring turnout. The aim should be leaving an average farm pasture cover of about 2,100kg dry matter (DM) per hectare (850kg DM/acre) and no covers should exceed 2,800kg DM/ha (1,133kg DM/acre).

Spring covers should be no more than 3,000kg DM/ha (1,214kg DM/acre).

--- Turnout onto covers of about 2,500kg DM/ha (1,011kg DM/acre) as this is the optimum sward height. This will ‘train’ the cows to graze the shorter covers. If they are moved onto longer grass later in the season they will have learned from their early season experience to graze it back to the optimum height.

--- Lower covers recover from grazing more quickly, so this is another reason why they should be grazed first in preference to longer swards, so the first grazed paddocks recover quickly for the transition to the second grazing rotation.

--- Cows do most damage to grassland when walking in and out, so it is preferable to graze fewer cows to ensure they can consume their target DM intake, which should be a minimum of 6kg DM/cow per grazing. Once the grass is growing and covers have increased in height, more cows can be turned out.

--- Ideally turnout freshly calved cows first as their appetites have not yet kicked in so they will be able to gain sufficient DM intakes from grazing.

--- Planning for the first grazing rotation so covers are grazed down appropriately will ensure the grazing platform is set up for optimum quality for the rest of the season.

IN THE FIELD: TRE IFAN, BRYNSIENCYN, ANGLESEY

RICHARD Rogers farms in partnership with Rhys Williams and Gethin Roberts at Tre Ifan, Anglesey. The farm was originally home to a large herd of suckler cows and a commercial sheep flock, but in 2015 the suckler herd was sold to make way for a spring calving, grass-based dairy herd.

In 2017, the sheep were also sold. Mr Roberts says the grassland management principles at Tre Ifan were already well established from 2012 when they adopted a rotational grazing system to finish Friesian steers.

“We cut and weigh the grass weekly through summer and every four weeks through winter to monitor growth and covers across the grazing platform.

We start planning ahead to the spring grazing season in autumn and keep good grass on the drier land ready for early turnout.

Calving

“This year, the grass has continued to grow exceptionally well throughout winter, averaging 8kg dry matter [DM] per hectare per day.”

Cows begin calving on February 7, so the first group is turned out from February 9 most years.

“This year, covers were about 2,700kg DM per hectare compared to last year’s figure of 2,300kg DM/ha. The aim is for 7-8kg of DM per cow per day from grass in February,” Mr Roberts says.

He anticipates ground conditions to be almost ideal this year, but when weather is less accommodating, they adopt a system of ‘on-off grazing’, which he says works well.

He adds: “If the paddocks are wet we will turn the cows out for three hours after milking. During this time they will eat 80-90 per cent of their required intakes and then we meet the deficit by feeding good quality silage back in the cubicles and supplement with concentrate fed in the parlour.

“Because they come in full from grazing, we find they do not eat much silage once inside. Plus, when they are outside they do very little damage to the ground as they are too busy eating,” Mr Roberts adds.

Waiting until the soil temperature exceeds 7degC and ground conditions are suitable means fertiliser is generally applied at the end February or early March, according to Mr Roberts.

Rotation

Grazing will be managed in accordance with the spring grazing planner through February and March. By April 1, the first grazing rotation will be concluded, calving will be nearly finished and almost all cows are turned out night and day.

FERTILISER AND EARLY GRAZING

MR Van Barneveld urges farmers not to be too concerned about applying early nitrogen before grazing, pointing out it is the management of grass which has far more influence on grass growth than fertiliser applications.

“If you do not apply fertiliser to grass before you graze it, you may lose almost nothing.

Growth rates

“Nitrogen is only an accelerator of grass growth, so to stimulate grass growth in the first place, it is vital to graze it. We have run trials which show nitrogen applied to grass which is not mown or grazed will not affect growth rates noticeably in late winter.”

Mr Van Barneveld’s tips for applying nitrogen in late winter:

• At temperatures below 8degC, applying more than 20kg per hectare (8kg/acre) may lead to unacceptable losses of nitrogen to the environment. As grass is growing at very low rates, it will use as little as 0.1kg N/ha/day (0.04kg N/acre/day)
• Rye-grass does not grow until soil temperatures exceed 6degC
• Urea fertiliser needs temperatures above 5degC to convert to plant available ammonia
• If the soil temperature is 2degC or below and soil moisture levels are high, between 70-80 per cent of the nutritional value of fertiliser may be lost
• For a minimum return on investment, aim to achieve at least 5kg dry matter of grass for every 1kg of nitrogen applied