Mowing grass before allowing the cows to graze it might sound like unnecessary work, but a farmer in Devon has found it has boosted peak yields from forage by 40 per cent. Jane Brown reports.
Maximising milk from forage is a sure-fire way to boost efficiencies at minimal cost, and pre-mowing seems to offer a relatively quick and easy way to boost grass intake.
At Brinsabach Farm, South Brentor, Devon, Bill Batten has been pre-mowing for about six years, and is delighted with the results.
“I was always trying to get more milk from grass, and went to a DairyCo talk about making the most of spring grass, which got me thinking about how to replicate spring grass all-year-round,” he says.
“I thought we could do it by continually cutting it. We could not get the highest intakes with grazing – a cow would eat 17kg by herself, but with pre-mowing that increased to 23kg. As a result, peak yields from forage increased from 25 litres to 35 litres a day.”
Before making the change, Bill would add concentrate feed for cows milking more than 25 litres a day in summer if it was dry, or above 15-20 litres if it was wet. That is now reserved for cows milking more than 35 litres.
“However, it has been difficult this spring – I have had to revert to more conventional feeding as we had used all the best silage and the cold weather meant we had a real lack of grass,” he says.
“We have had to feed a lot more concentrate than normal.
Another impact of the cold spring has been all the grass has grown at once.
“We usually have a wedge of grass ahead of us but we have lost that, so some has gone to seed – we have had to take more out for silage than normal.”
Bill and his son John measure grass growth by eye, and graze cows rotationally, shutting up any paddocks for silage if the grass gets ahead of them.
“We will usually cut once-a-day: at busy times you can cut enough for two days but you really want it as fresh as possible,” says Bill. Typically, he will cut the grass when it reaches 3,000kg/hectare or 1,215kg/acre (of dry matter, leaving 1,700kg/ha or 687kg/acre residual for rapid regrowth).
“It takes about half-an-hour each day with a 90hp tractor and seven-foot mower, plus the diesel.”
The pair use electric fencing to strip graze the paddocks, moving it four times a day to encourage the cows to get up and graze again.
John says: “They get fresh grass after milking in the morning and evening, again at midday and in the late evening. If we gave them the full amount they would walk over it and waste it; we want them to be motivated to get up and eat again even if they are not hungry – it is like going back for dessert.”
Another benefit of mowing the grass is the cows eat all of it: the energy-rich top and the fibre-rich base.
“They are not selective like they would be when grazing.” And an unexpected boost has been the impact on weeds, says Bill.
“Nettles and thistles are a thing of the past, although docks are the bane of my life.”
Typically, the Battens do not start mowing until after the first or second grazing, as there is not sufficient grass to warrant it.
“But we do cut whatever the weather, and can cope with grass wich is grown a bit too far – something you would not really graze,” says Bill.
Youngstock are also treated to pre-mown pasture, and each paddock gets 35 units of urea/acre after every grazing, providing rain is forecast.
“We then test the soil and top up with potash and phosphate in autumn. We house the cows on sea sand in cubicles over winter, and spread that on the land so there is no need for lime as it keeps the pH high.”
Perhaps surprisingly for farmers so reliant on forage, the family haven not reseeded any of their pasture since the 1960s.
“We were in an Environmentally Sensitive Area for 20 years on the improved permanent pasture tier, so could not reseed,” says Bill.
“We are no longer in the scheme but I am not sure we want to reseed. We have got mixed species and a thicker sward than reseeded leys – and I have read high intakes of high sugar grasses can increase the risk of acidosis.”
In a trial carried out by Mole Valley Farmers on a field not reseeded since World War Two, grass yields in May totalled 3,500kg DM/ha (1,414kg DM/acre), dropping to just over 2,000kg DM/ha (810kg DM/acre) per month over the summer months and 1,760kg DM/HA (710kg DM/acre) in September.
“If we add in 1,500kg for the shoulders of the year it brings the total to a very respectable 13,900kg,” says Bill.
Protein content ranged from 11.4 to 22.4 per cent, with metabolisable energy at 11.3-11.5MJ.
The fields are left to regrow for a month before being grazed again.
“Typically we will cut 12ha of silage here and then buy-in some bales which we remove the net from and put into the clamp – it is more efficient to transport that way,” he adds.
“We are constantly adding to the silage pit; as we are spring calving the cows are usually in late lactation by the time they are eating it. However, we want to be as self-sufficient as possible so may reduce cow numbers a bit so we do no need to buy-in silage.”
Bill houses the cows over winter, feeding them just silage if it is good enough quality, and adding in soya hulls or rolled maize if necessary.
“We use feeders so there is no need to push it up, but we keep them clean and fresh; our whole system is geared to maximising forage intake, which is what everyone does over winter, but very few seem to focus on in summer.”
"Having such low input costs is certainly helping us enormously"- Bill Batten
The farm also has self-locking yokes which Bill uses to feed a mineral blend each day – 0.5kg gives them all the minerals they need.
“The yokes are also really useful for vaccinating, AI, tail painting and so on.”
He dries off the cows for two months before calving, which runs from early February to mid-June.
“It would be nice to have a tighter block but on a small farm we just can not afford that luxury as it is very wasteful – even if you have a conception rate of 60 per cent you are still going to be losing cows.”
The cows are typically housed from about mid-November and are turned out again after calving.
“We snatch the calves to protect against Johne’s and to stop the cow bonding with the calf,” says Bill. “We milk the cow as soon as she’s licked the calf dry and then feed it the colostrum.”
Calves are housed and fed whole milk until weaning at six to eight weeks of age, after which they are turned out.
“We keep our own replacements and sell others to a local calf rearer,” he says.
Heifers calve at two years old, and all the females are artificially inseminated, with no bulls kept on the farm.
Although the herd was originally British Friesian, Bill has crossed the cows with New Zealand Friesian and Norwegian Reds, with Fleckvieh being trialled as a third cross. On average the cows yield 6,403 litres at 4.26 per cent fat and 3.47 per cent protein. The calving index is 380 days, and in 2014 Bill spent £23.90/cow on concentrates (2015 accounts are not yet prepared).
“Before we started mowing we were using one-tonne of concentrates per cow – in 2014 it was 100kg although that was a very good year – on average it would be about 200kg,” he says. “The milk quality has not changed, and we do not get any displaced abomasums or other concentrate-related problems.”
At a time of very low milk prices, having such a low-input system really pays dividends.
“Our profit halved in 2015 because of lower milk prices, but it remained a profit,” says Bill.
Although the herd output is lower than average, the variable costs in 2014 were £362 per cow compared to a UK average of £928 for mainly Friesian/Holstein herds, according to the Farm Business Survey, to which Bill contributed. That put his gross margin at £1,427/cow compared to an average of £1,170/cow.
Supporting nearly three families – Bill, John and his sister Susannah, who does the herd records and milking – on such a small farm is a tall order, but one this system is helping to deliver.
“Like anyone else we are not going to make a lot this year but having such low input costs is certainly helping us enormously.”