Rotational grazing of sheep to make more efficient use of grass can reduce feed costs and improve pasture productivity. Chloe Palmer talks to the experts to learn more.
Many sheep farmers waste more than a third of the grass on their farm because they do not plan grazing wisely.
This is according to Susan Buckingham, extension officer at the Institute of Biological, Environment and Rural Sciences grassland development centre at Aberystwyth University, who has worked with farmers to optimise grazing efficiency.
“Farmers who achieve excellent utilisation rates will be using 80 per cent of their grass, but on many farms the figure is nearer to 50 per cent.
“This wastage results in higher feed costs, both in terms of conserved forage, which is twice as expensive to produce as grazed grass, and bought-in concentrate, which costs four times as much.”
Mrs Buckingham says rye-grass plants only maintain three live leaves at any one time, so if the grass grows beyond this stage, leaves will die off and the sward will become less nutritious and palatable.
“Dairy farmers have grazed using this principle for several decades now but for sheep and beef farmers it is more difficult to manage grazing exactly as they are not dealing with a set herd size or age profile.”
Mrs Buckingham says adopting a rotational system where sheep move onto new grass every few days is the best way to manage grassland because it allows plants to recover, so yield is maintained.
“The first stage is to measure grass so you can estimate the amount of dry matter available to the flock.
“A plate meter or sward stick is fine for this and, although mobile apps are available for recording the data, a simple spreadsheet or even paper records are equally suitable.”
A dry ewe will eat 1.5 per cent of its body weight in dry matter each day and an early lactation ewe will eat 3 per cent, she says.
“Once you have calculated the grass you have in a paddock, it is possible to calculate the ration for the size of flock which will be grazing it. Creating smaller paddocks using electric fencing can be considered as it can result in less wastage and longer resting periods for the sward.”
Choosing the right system for each farm is critical, she says. The one-size-fits-all approach, which can work in New Zealand where farms are more standardised, needs to be adapted to suit UK farms.
“Dividing fields using electric fences is not suitable where you have horned breeds. Similarly, rotational grazing in winter is unlikely to suit wetter farms on heavier land due to issues with poaching.”
Mrs Buckingham urges caution where farmers are thinking of adopting a rotational method when in an agri-environment system.
“Rotational grazing creates even sward heights in most situations and these are not usually compatible with prescriptions for agri-environment grassland options.”
For farmers with grassland in an agri-environment scheme agreement which has recently expired, Dr John Vipond of Scottish Rural Colleges believes paddock grazing can help to restore the sward’s productivity.
He says: “Where pasture has deteriorated under a low-input regime, paddock grazing will encourage the perennial rye-grass to flourish.
After two to three years, a significant increase in the cover of productive species will be observed.
“Paddock grazing can also work well alongside over-seeding. If grass seed is broadcast across a field in March which is then paddock grazed afterwards, the sheep will push the seed in with their feet.
Dr Vipond says a stocking density of 500-1,000 ewes per hectare (202-404 ewes/acre) is required on one- to two-day shifts in order to achieve pasture improvement through ‘hoof and tooth regeneration’ and when broadcasting rejuvenation seeds.
“The nutrients from dung and urine will aid grass establishment and it is a cost-effective way of rejuvenating swards without having to cultivate.”
Dr Vipond has led research into all-grass wintering, working initially with farmers in the South West before extending trials to farms across England. The farmers build up a wedge of grass through autumn and feed it back to ewes through winter using a daily shift system.
“We start by grazing paddocks nearest the lambing shed and move away gradually. By the time ewes are lambing, there will be sufficient grass on the original fields close to the buildings for ewes to lamb there.”
Farmers who have adopted this system, such as Keith Williams of Hendy Farm, Llandrindod Wells, have found it reduces the amount of conserved forage required and they have bought-in less feed.
“Last year we saved six weeks’ worth of silage. This year we will be saving two months’ worth,” he says.
Mr Williams first started rotational grazing in 2008, following a visit to New Zealand. Since then he has modified his system, grazing the flock in larger groups to ensure paddocks are grazed off more quickly.
“We now graze groups of 300-350 ewes on paddocks up to a maximum of six acres in summer. During winter months, the system is more intensive, with 400 ewes grazing one-acre paddocks and moving daily.”
Mr Williams initially invested £4,000 in electric fencing and recently bought an attachment for his quad bike allowing him to quickly lift and move fences.
He says: “The day-to-day management for paddock grazing is not very labour-intensive once set up. We split most of our fields into two with a permanent electric fence and then use temporary fencing to create smaller paddocks as we need them.”
Most grassland consists of long-term leys, but Mr Williams is now establishing a crop of forage rape and hybrid kale on one field each year to finish lambs in autumn. This field is then reseeded with a perennial rye-grass and white clover seed mix.
Extreme weather can, he says, be particularly disruptive and he had to abandon his all-grass wintering system in January 2013 during a period of exceptional rainfall.
“This winter has been much easier and we have been able to move sheep onto fresh grass until February. Now we will feed them silage in a sacrifice feeding area until lambing.
“We rarely have grass before the end of April, but this system means we can lamb them onto fresh pasture.”
For Mr Williams, the system has been a means of lowering costs and he believes this is crucial for a sustainable future.
“I believe lamb is close to pricing itself out of the market. If consumers are to continue buying it in preference to cheaper alternatives, we must produce it as cheaply as possible.”
Mrs Buckingham urges others who are considering adopting rotational grazing on their farm to ‘pick a system and have a go’.
She says: “Farmers have to be interested and committed to making rotational grazing work on their farm. There is a time commitment and it can take up to six years to get everything exactly right, but farmers will then see the benefits for the flock and grass.”
Target sward height for sheep
|Class of stock||Grazing period||Rotational Grazing|
|Pre-graze (cm)||Post-graze (cm)|
|Ewes and lambs||Turn-out - May||8 - 10||4 - 5|
|May - weaning||8 -10||4 - 6|
|Pre-tupping||Sept – November||8 - 10||4 - 5|
|Weaned finishing lambs||July - September||10 - 12||5 - 7|