For Profit from Grass farmer George Brown, preserving grass stocks is now key as grazing starts to slow down, and we get advice on correct soil aeration protocols.
Winter feed budgets suggest silage stocks will be tight for the 425-head spring-calving herd managed by Profit from Grass farmer George Brown at the Craig family’s Cairnhead Farm, Ainstable, Cumbria.
This is despite a bulky second cut taken in mid-July off 100 hectares (247 acres) and overlaid with 13ha (32 acres) of wholecrop in early August.
Mr Brown says: “This summer, the grass season has completely turned around for us. We had a relatively light first cut, due to the slow start to the grass season, but in contrast, in August, growth averaged about 85kg DM/day and was still in the high 70s through into September.”
The bulky second cut and wholecrop spring barley, undersown with grass seed, has been layered into the farm’s only silage pit.
This will be metered out during winter at a feed budget averaged at 14kg DM/head/day for late lactation and dry cows.
“It does mean first cut, which should be better quality, gets left until the end of winter to support heifers in early lactation next spring.
“We have sufficient silage to allow us to fully feed all stock on-farm with silage alone for a three-and-a-half-month winter. The reality is not all cows and heifers will stay indoors for that period, or for that matter youngstock which have been allocated a feed budget of 8kg DM/head/day.”
To ease pressure, Mr Brown has been tightening up on the grazing round to build up the farm’s average cover to its level of 2,700kg DM/ha (1,092kg DM/acre).
He says: “We have continued to follow cows with an application of 100kg/ha of 33 per cent nitrogen fertiliser. Also, rather than chase a third cut, we shut up the silage ground for 40 days and the standing silage has been grazed by cows to preserve the grazing platform.”
The grazing round will length from 30 days in early September to 40 by mid-month. To preserve grazing further, all milkers have had the daily allocation of concentrate increase from 1.5kg to 3kg/head/day by early September.
Mr Brown says: “On our system and milk price, it does not pay to feed concentrate for production alone. But it might be justified if it helps us keep cows out grazing later this autumn.”
In early September, the 406 milkers were averaging 18 litres of milk/head/day at 1.5kg of milk solids.
Grass growth is expected to decline quickly as the calendar moves towards October, at which point daily growth will be down to about 35kg DM/ha/day (14kg DM/acre/day) against a target demand of 50kg DM/ha/day (20kg DM/acre/day).
“In late September, we will scan the whole herd, including heifers, and anything empty will be culled. We will not carry passengers.”
Bulls came out six weeks ago. An eye will be kept on cow body condition, which is likely to be high, given the simple feeding system and relatively good quality winter forage available. But for now, preserving grass stocks is key.
Mr Brown says: “Early spring aside, it has been a phenomenal year. From May 1 to September 1 we grew 9.97 tonnes/ha, which compared to 2014’s 5.6t/ha is a vast difference over the same period.”
September is a good time to aerate grassland soils, according to AHDB Dairy’s senior dairy scientist Dr Debbie McConnell. But care should be taken to ensure there is actually a need to carry out aeration and soils are in the right condition to benefit.
Dr McConnell says: “Aeration is time-consuming and can be costly, at up to £70/hectare, and if it is carried out in the wrong conditions, soils can be prone to recompaction after it has been done.”
However, she says failure to put right compaction can cut 10-20 per cent off grassland yields through poor rooting and nutrient uptake, increased soil erosion and nutrient loss, and the generally poor heart of the soil, through a lack of oxygen and diminished biological activity.
So she suggests assessing the situation in September – a month in which sward productivity has started to drop off, so minimising the yield penalty from the disruptive aeration, yet when the soil can still be dry enough to travel on and for the process to be effective.
She says: “Aerating late in the season allows the field time over winter to settle into a new structure before receiving animal or machinery traffic in spring.
“Once you have decided aeration is required, you need to make sure conditions are right to undertake the process.
“Make sure you check conditions at the depth at which you want to aerate. Conditions on the soil surface can be different from those at depth, so it is important to dig a hole and assess soil moisture at the proposed aeration depth.”
This can be done by rolling a handful of soil into a sausage shape.
She says: “If the soil has a moist, smooth surface, it is too wet to work, but if it starts to crack it is suitable for slitting or sward lifting.”
More information on aeration can be found at www.healthygrasslandsoils.co.uk