By Debbie James

Boosting grass leys by over-seeding is proving a cost-effective option for maintaining sward quality at a Carmarthenshire farm.

Ioan Davies adds seed to approximately 20 acres of existing leys at 300-acre Penlan Farm, Llanwrda, annually.

Mr Davies, who produces milk from a herd of 200 cows, says this approach generates an obvious improvement in grass yield and forage quality at relatively low cost and risk.

The seed is drilled in August, either after a field has been grazed hard or after third crop silage has been cut. This minimises competition for the new seedlings from the existing grass.

Mr Davies mostly uses PRAg Hi-D over-seed but also HSG 2, a tetraploid silage mixture which he says works well as an over-seeding mixture because it is vigorous and competes with the older sward.

He hires a contractor to drill the seed at a cost of £25/acre; a plough and reseed combination would cost him £65/acre – £25/acre for a contractor to plough and £40/acre to power harrow twice.

Not only is there an obvious cost saving to over-seeding but the field can be grazed soon afterwards.

“When we plough a field it is out of the rotation for two months but in a field that has been over-seeded we apply a thin layer of slurry with a splashplate after 10 days and it can quickly be back in use again,’’ Mr Davies explains.

An over-seed gives tired swards a useful flush of young grass and boosts more productive species.

Mr Davies admits he doesn’t reap the benefit until the following growing season because the seed is drilled late in the season but the field can still be used.

“Spring would probably be a better time to do it but there are always multiple jobs to do in the spring – spreading fertiliser and slurry – that it works better for us in late summer.’’

Mr Davies and his wife, Catrin, run a flying herd of mainly Holstein Friesians, British Friesians, crossbreds and Ayrshires, producing milk all year around at an average yield of 8,500 litres at 3.95% butterfat and 3.32% protein.

They adopted this approach five years ago after losing the unit where they reared their calves but Mr Davies says the system is a better one.

“We had been struggling to get cows to calve at two and a half years and have found that it works out cheaper to buy in heifers and cows rather than rear our own.’’

Cows, which are milked twice a day in a 24/48 herringbone parlour, average 7-8 lactations, with milk supplied to Fairfields.

“When I came back to farm 17 years ago we were producing 400,000 litres from 60 cows but now it is 1.8 million litres from 200 cows,’’ says Mr Davies.

The cows are at grass for seven months, from the beginning of April to the end of October, but are housed at night throughout the year.

“We had a very wet spell in 2012 and started housing at night and have done so ever since because it means they can have all the goodies in the TMR at night and not poach the fields when the weather is wet,’’ says Mr Davies.

The TMR includes a 16% protein blend – 22% in the winter – molasses, grass silage, minerals and an energy supplement.

This ration is fed for 23 litres with cows producing above this topped up with concentrates in the parlour, up to a maximum of 9kg.

It is the performance of cows at grass that dictates which fields Mr Davies earmarks for over-seeding.

“The cows will soon let us know which fields are not performing because we will notice a difference in their yield,’’ says Mr Davies.

Those fields have generally not been ploughed for more than 10 years. By the time a long-term ley reaches this point more than 40% of the sward is likely to comprise of weed grasses and broad-leaved weeds.