Grass quality is absolutely critical to the Calver family’s business. As artisan cheesemakers in Somerset, they produce unpasteurised cheeses including Cheddar, ricotta and Caerphilly; the taste of which is influenced by the cows’ diet.
The Calver family are artisan cheesemakers. Richard Calver, who manages the farming side of the business, says: “When we were grazing the cows day and night we found the flavours of the cheese were more variable as the weather changed, so we now house them overnight with a buffer feed to improve consistency. We’re supplying a high-end market, so flavour and consistency are absolutely vital.”
Mr Calver has two dairies at Westcombe Farm, near Shepton Mallet; one milking 180 cows and one with 200 cows. Until recently they were all pedigree Friesian, although there is now a small herd of pedigree Ayrshires as well.
“We calve at two years old, from June to January, and house the cows over winter from November until around mid-April,” he explains. The cows then graze rotationally over summer, moving to fresh pasture about once-a-week.
“The grazing leys are located close to the dairies, with further off fields in an arable/ silage rotation or permanent pasture which is grazed by the youngstock. We’re on quite wet land here, so the ground doesn’t lend itself to intensive grazing.”
Although the cows start the season grazing a relatively small area around the dairy, they move to some silage fields after the first cut and then out again after the second and third cuts, until they end up grazing most of the farm.
The farm has around 40 hectares of wheat for crimping, 73ha of maize, and 200ha of grazing and silage leys with some steep permanent pasture.
“We plant wheat after maize and then reseed about 40ha of grassland each year – as we cut the wheat early for crimping we can establish the grass behind it at the end of August,” says Mr Calver.
When it comes to choosing grass varieties for silage, agronomist Keith Hallett, of Pearce Seeds, recommends high-quality, high-yielding Italian rye-grasses. A typical mix will include a hybrid Italian rye-grass. A 13kg mix will also include 4kg of red clover to fix atmospheric nitrogen and provide protein in the diet.
Grazing leys comprise high sugar diploid perennials.
“These varieties have more leaf and less stem, so although yield will be lower quality is higher and they are longer lasting,” says Mr Hallett. “Although we didn’t use any white clover this year due to a problem with docks, we usually add about 1kg in a 15kg seed mix.”
The key to preventing weeds in new leys is to get the grass established and to tackle weeds at an early stage, says Mr Hallett. “If you allow weeds to get their roots down and go to seed you’ll be fighting a losing battle.”
He recommends spraying new leys with fluroxypyr and Lupo (a mix of MCPA and 2,4-D) to control chickweed, thistles, buttercups, docks, ragwort and nettles.
“The problem with new leys is that stronger herbicides can check young grass – and the presence of clover will complicate weed control programmes as it limits your herbicide choice.”
Amidosulfuron is one of the few herbicides which can safely be used on clover leys, he adds. “In older pasture I’d recommend a 2,4-D and dicamba mix, which has stronger action against docks and ragwort – but it can’t be used on clover.”
Mr Calver usually reseeds his silage leys every two to three years, with grazing leys down for between five and nine years, depending on condition.
“We like to have quite a lot of variety in the longer term leys as it can really influence the flavour of the milk.”
He typically takes three cuts of silage, and last year tried to cut earlier and more regularly to boost quality. “We took the first cut at the start of May but then it rained solidly for six weeks, so the second cut was later than we’d have liked,” he explains.
He uses a contractor with a self-propelled forage harvester but relies on farm labour for all the other forage jobs. “We have a few different silage clamps, so we can keep the first and second cuts separate.”
Although he aims for about 30% dry matter, last year it was almost 39%, with metabolisable energy of 12.1MJ/kg, a D Value of 67 and protein of 13.5%. “Yield was about 16 tonnes/hectare fresh weight for first cut and 11t/ha for second cut.”
Mr Calver feeds the winter ration and summer buffer feed through a mixer wagon, using grass and maize silage in equal volumes on a dry matter basis, plus soya, sugar beet, rape meal and crimped wheat.
“We also chop straw and hay and mix it into both the milking and transition diet; it improves the butterfat and protein content of the milk enormously,” he says. “The mixer wagon cut it a bit too long – using a straw chopper is better, and the hay definitely influences the flavour of the milk.”
Milk yields average 8,600 litres in the older unit and 9,200 litres in the newer unit, with protein and butterfat at 3.3% and 4.2%, respectively. Milk from forage averages around 3,500 litres.
“I built the older unit 34 years ago and the newer one five years go – we’ve learnt a lot in that time,” says Mr Calver.
He visited other cutting- edge dairy farms and copied the best of their designs. “The new unit is light and airy, with wide passageways and plenty of space – we definitely get higher dry matter intakes as a result.”
Mr Calver and his son Tom, who runs the cheesemaking side of the business, believe happy cows make better cheese, and they handle the milk equally carefully. “We don’t like to shake it about, so we have slow, gentle milk pumps and fill the bulk tanks from the bottom.”
The cows are housed on sand cubicles, and Mr Calver spreads the slurry throughout the growing season. “We’re not in a Nitrate Vulnerable Zone, so we get on as early as conditions allow in January. We use a contractor and are hoping to start injecting it rather than using a splash plate,” he says.
He then applies 60-75kg/ ha of ammonium nitrate to the grazing leys two or three times over the season, with silage ground getting 87-100kg/ ha after each cut. “We don’t need to apply any phosphate or potash because that’s supplied through the slurry.”
The main weed problems on-farm are docks and chickweed, with bracken on the steep permanent pasture. “We spot spray docks, and are busy tackling the bracken now,” says Mr Calver. “We were in a stewardship scheme which meant we had to delay grazing, so bracken really got a foothold. Now we’re out of the scheme we’re spraying it manually and then using a remote controlled vehicle to flail it, as it’s too steep to access with any other machine.”
The best time to spray grassland is when the weeds are actively growing in spring, at the rosette stage, says Mr Hallett. “Once the weeds are established you’ll probably have to spray for two seasons running because as quickly as you kill one generation the next seeds are growing.”
Docks, chickweed and dandelions can also be controlled by grazing grass down harder – as can crown rust, which was prevalent over autumn due to the warm and wet conditions. The warm autumn also resulted in rapid proliferation of chickweed in established leys.
“It can quickly swamp grassland so I would spray it with fluroxypyr up to October, with a 2,4-D, dicamba and MCPA mix if there’s no clover to protect.”
Farmers could boost their dry grass yields by 18% – and extend the grazing or cutting season – by applying SmartGrass, a natural growth promoter containing gibberellic acid. According to Dick Dyason, technical manager at Nufarm UK, rye-grass requires gibberellic acid to grow: It aids cell division; speeding up growth rates and boosting yields, and is a limiting factor for regrowth following cutting or grazing.
Chris Knowles produces milk from grass with spring-calving cows at Trink Farm, St Ives, Cornwall, and has benefited from extending his earlier grazing.
“Our farm is surrounded by water so it is slow to warm up in spring, so any boost to early season growth is important,” he says. “We graze the cows in rotation from mid-February, so need the pastures which are grazed early to be ready for grazing again in April.”
Mr Knowles takes weekly plate meter readings to monitor the grass growth and usually aims for 2,800kg DM/ ha before grazing.
“Last spring I applied SmartGrass on April 18 to half a pasture three days after removing the cows, leaving the other half untreated,” he explains. “On the treated area the threshold of 2,800kg DM/ha was achieved seven days earlier than the untreated. This growth boost means I can bring the early grazed paddocks back into the grazing rotation sooner.”
Mr Dyason adds: “In one trial where we sprayed pasture with gibberellic acid, the subsequent silage yield was 55% greater by weight, and although there is an increase in bulk there is no reduction in nutritional values.”
It is important to apply the growth promoter within three to five days of grazing or cutting, and to make sure the grass is then grazed or cut at the optimum time afterwards, warns Mr Dyason. This may mean making a subsequent silage cut up to a week earlier than normal. “Once rye-grass has three leaves it’s reached its optimum growth stage – when it grows a fourth leaf it will drop the first one off, so you’re getting more stalk and less quality. There’s no point increasing yields and speeding growth rates if you’re not going to reap the benefits.”
It is also important to ensure the grass has sufficient nutrients and moisture to fuel that extra growth rate and yield, or they will become limiting factors themselves.
It is important farmers understand the real cost of weeds, warns Mr Hallett. “Docks and nettles can shade out grass, leaving bare patches where more weeds can germinate. If grass silage is worth £25/t, and good pasture is yielding 29t/ha fresh weight, weeds can reduce to 17t/ha and lower the quality. That will cost you nearly £310/ha, compared to a reseed cost of £250/ha.”
In permanent pasture which cannot be reseeded, Mr Hallett suggests keeping the grasses healthy through good fertiliser management. “Docks and thistles scavenge for nitrogen, so once the grass has used the nutrients in the upper levels of the soil the weeds will take it from lower down, making the weeds stronger and the grass weaker. If you keep your grass healthy, and top it up with productive grasses when you have poached or bare patches, that will prevent weeds from growing up.”
Weeds are also an indication of a problem in the grassland. “Rushes indicate poor drainage, and chickweed thrives in poached areas, for example,” Mr Hallett explains. “You need to look at the whole picture, not just at the herbicide choice.”