Using the dairy cow to make the most of your grazed grass.

GrassCheckGB participant, Andrew Brewer, hopes to graze his 600 dairy cows for 365 days of the year to maximise the use of grass on his coastal Cornish farm.

While much of the dairy farming community is preparing to bring (or has brought) cows in for the winter, Andrew Brewer, who farms at Ennis Barton near Newquay in Cornwall, is setting up his next grazing round.

With the aim of grazing his 600 autumn calvers for 365 days a year, his November round will involve feeding roughly 100th of the grazing platform every day.

Grazing some 190 hectares (470 acres) in total, this means 1.9ha (4.7ac) will be allocated to the herd each day. The opening covers will be roughly 3,000kg dry matter per hectare; they will be grazed down to 1,500kg DM/ha, supplying each cow with just under 5kg of dry matter intake (DMI) per day.

“We reckon on grazed grass supplying roughly 30 per cent of their daily DMI at this time of year,” says Mr Brewer. “Just under two hectares feeds all 600 head, but they will consume it in around three hours.”

This means the farm operates a system of ‘on-off’ grazing through the winter, usually turning cows out after morning milking and bringing them in around lunchtime. They will then self-feed grass silage and receive a smattering of concentrates in the parlour, bringing the total DMI to an average 17kg per head per day.

The upshot is that the herd of New Zealand Friesians x Jerseys yields around 5,500kg at 4.7 per cent fat and 3.6 per cent protein (305 days). This is achieved from a ration comprising a simple combination of grazed and conserved grass and just 700kg concentrates per cow per year.

The grazing round through winter will last for 100 days, meaning the cows will have returned to their early November paddock by 10 February.

During that time, they will also have grazed a small field of fodder beet, which will be sufficient to keep grazing going through the winter months.

“This helps keep the cows full during the winter, and if they are full, they will be happy,” he says.

Good grazing management throughout the whole season ensures the cows at Ennis Barton are entering winter in good condition, which is critical to their ongoing success as insemination of the tight block-calving herd also takes place.

“They are in far better condition now than they were last autumn as they’ve had a great summer, a drier autumn, and autumn grass utilisation has been better than last year,” he says.

“This is critical as we start breeding, which is probably the most important three-week period of the year,” he says. “We want the cows to be in optimum condition, with minimal lameness and other problems and body condition scores of 2.75 to 3.

“I’m happy they are meeting this BCS target, with very few cows outside that range,” he says, remarking that the target dates for calving are a nine-week block from early August to 1 October, with Hereford bulls sweeping up after the main insemination period.

Despite the good autumn conditions, the 2020 grass growing season was marred by the drought in spring, which has hit the annual dry matter yield per hectare.

This has been monitored through Mr Brewer’s participation in GrassCheckGB, an industry, academic and levy board collaboration designed to help British farmers improve their grassland management.

“Our grass dry matter per hectare has so far been 10.7 t which compares with 12.1 t for the same period in 2019,” he says.

This is typical of the situation across the UK, according to Dr Kathryn Huson, a research scientist with the Agri-Food and Bioscience Institute (AFBI), a partner in the scheme.

She says: “Undoubtedly the weather in 2020 has had an impact on grass production. Grazing yields from the 50 farms in the GrassCheckGB network are, on average, 1.4t DM/ha below figures recorded in 2019.

“This is due to lower grass growth rates in April to June, when extremely dry conditions were seen across the country. Last year GCGB farms saw average yields of 11.0t DM/ha whereas this year the overall average is just 9.5t.”

She says building flexibility into the system is key to making the most from grass in any year.

Mr Brewer concurs and says that closely monitoring grass production through the GrassCheckGB project has ensured the greatest utilisation is achieved of the highest quality grass.

He says: “The timing of silage making depends entirely on the season, but we expect to shut ground for silage in March or April and are prepared to cut at any time.

“We generally cut very early and have a light crop to maintain the quality of grazing through the season,” he says. “Whenever we have a surplus we will cut, which is likely to be every 28 to 30 days.”

For the future he says he will drive both quality and production from his swards by regularly monitoring their performance and working on the bottom 10 per cent of the farm.

As with his cutting regime, reseeding is undertaken according to performance rather than date, and some of the oldest swards on the farm are also the most productive.

“We retain our leys for as long as they are productive, and some of our most productive are more than 20 years old – effectively permanent pasture,” he says. “Some of our top 10 per cent have never been reseeded; I feel that if it’s producing well, why would you destroy it.”

In the long term, he will continue to check soil compaction along with pH, phosphate and potash, and sward lift where necessary using a Sumo GLS.

“It’s so important that farmers are involved with projects like GrassCheckGB,” he says. “Farmers can help researchers by bringing practical knowledge and researchers can help us as farmers.

“We now consider ourselves to be grass farmers more than we’re cow farmers – we utilise the cow to utilise the grass we grow.”