A guide to all-grass wintering sheep
© Tim Scrivener Grass growth may be minimal over the winter months, but grazing at high intensity and in a controlled fashion over winter could cut feed costs and increase the productivity of grass the following spring.
John Vipond of SAC Consulting and Poppy Frater of EBLEX answer some frequently asked questions.
See also: 5 steps to managing your flock’s forage at winter
What exactly is all-grass wintering?
It is an intensive rotational grazing system with high stocking densities. The sheep are moved frequently through electric-fenced paddocks, and fences are moved to mark out an area for grazing.
The sheep graze on the grass that has accumulated for the winter plus winter-grown grass. The grass is measured and dry matter calculated so that the ewes are given exactly the amount they require.
Can any farm adopt all-grass wintering?
Wintering ewes mainly on grass is feasible and low cost on favoured farms in south-west England, but requires free draining soils, and an average winter for grass growth.
In more northern locations and at altitude more supplementation will be needed. Budget 10 days (10% of the winter) full feed when ewes are off the rotation and be prepared for housing at lambing if little or no winter grass grows.
Estimating ewe demand and grass supply
Ewe nutrition demand and grass DM supply has to be estimated to calculate a feed budget and determine paddock set-up.
Pre-scanning
For ewes being managed in an AGW system, the correct amount of grass dry matter to allocate daily to ewes in kilograms of dry matter is based on 1.5% of bodyweight up to scanning. After scanning, this must be increased to 2% of bodyweight.
General intake requirements for different classes of sheep |
|
| Stock | Intake requirements (% of bodyweight) |
| Dry ewes Mid pregnancy ewes |
1.5 |
| Late pregnancy ewes | 2.0 |
| Mid to late lactation ewes | 2.5 |
| Early lactation ewes | 3 or more |
| Growing lambs | 4.0 |
| Source: All-grass wintering sheep (PDF) Poppy Frater and Dr Liz Genever, AHDB Beef & Lamb, John Vipond and Rhidian Jones of SAC Consulting | |
Worked example for 65kg ewes on daily shifts
Demand in mid-pregnancy is: 65 x 0.015 (1.5%) = about 1kg DM/ewe/day
This allows for 15% wastage, as DM intake will be 0.85kg/day. Note, on 2-3 days shifts, waste will be 15-30% and therefore allocate more.
Demand in late pregnancy is: 65 x 0.02 (2%) = 1.3kg DM feed/ewe/day
Can any ewes by grazed on this system?
Most UK ewe maternal breeds are suitable for the system.
Does grazing at high stocking density not damage the grass?
High stocking density, despite the short-term trampling damage, soon results in grass recovery if the grazing duration is short, weather not ridiculously wet, and the recovery period long.
When ewes, however, are stocked for long grazing periods in winter the opposite occurs, they graze and poach for longer periods causing significant damage, nibbling off precious regrowth and stunting recovery.
How many grazing cells and land area will I need?
100-110 separate grazing cells are typically used at a rate of one a day to ration out an initial grazing wedge of up to 2,000kg/ha DM of grass (10 cm).
This together with regrowth of up to 10kg/ha of DM a day in favourable areas of south-west England allows an outdoor lambing (April-May) with very little need for supplementary concentrates or forage.
How long can I graze for?
This system is used for just over 100 days. From pregnancy, approximately three weeks after mating, until three weeks before lambing.
Where winter grass growth is 0-5kg/ha of DM, grass can be grazed until it runs out with supplementation of concentrates fed at grass for a fortnight before ewes are housed for lambing.
On either system plans have to be in hand to take sheep off the rotation if heavy snow or flooding occurs.
Source: All-grass wintering sheep (PDF) Poppy Frater and Dr Liz Genever, AHDB Beef & Lamb, John Vipond and Rhidian Jones of SAC Consulting
Is it expensive to set up?
AGW sounds like a lot of expense and work but it’s not. A small portable water trough on winter grass meets farm assurance purposes and will suffice as sheep take no water on grass only diets at 15% dry matter.
A mechanised electric fencing system costs about £3 a ewe to buy, lasts for years and is easy to use.
How much can I reduce my feed costs by?
The reduction in feed costs from grass-based diets was estimated in trials last year at about £15-18 a ewe compared with housed systems in favoured grass growing areas.
Savings will be considerably less on farms that can graze for part of the winter only. Recent NZ studies show four-day shifts work just as well over there but this has not been tried in the UK yet.
Case study
Dorset sheep producer Mike Miller is one farmer who can vouch by the benefits of all-grass wintering.
It may not be a term that is familiar to many, but the New Zealand concept is based on cell grazing grass where sheep are managed at high stocking densities and moved frequently through electric fenced paddocks.
Mr Miller, who runs 1,200 commercial Mule ewes and New Zealand Romneys, share farms with Langham Farms and has a lot of outlying free-draining chalk land and permanent pastures.
He was already outwintering his sheep all year previously, but he was getting to February and running out of grass and haylage.
Setting up the system
So working with EBLEX and John Vipond of SAC Consulting, Mr Miller set up his system. Fields were shut up from mid-September onwards by using electric fencing. The plan was to start grazing sheep in mid-December with a grass wedge of 2,900kg/ha of DM.
Any ewes with condition scores too low were pulled out of the system, leaving 780 Mules and Romneys going into the all-grass wintering system.
“We had about 100 acres and 780 ewes were moved daily and grazed on about an acre a day.” Mr Miller also had a sacrifice paddock that could be used if there were any problems such as snow on the ground, so sheep could be supplementary fed without damaging the main grazing paddocks.
Mr Miller says through to scanning ewes were on a set amount of grass, but after scanning singles and twin bearing ewes were split with twins receiving an increased daily allowance. The aim is to maintain a level condition score throughout winter of about 3.
Benefits
As a result of all grass wintering Mr Miller has seen several benefits. “Not only have we managed to keep ewes in a good condition and seen a reduction in prolapses in the Romneys, the pasture quality has also improved as the dung and urine is spread out right from the top of the strip to the bottom. It has also helped reduce feed costs and the ration quality is kept constant for the ewes,” he says.
However, the one downside is the added labour time. “It is labour intensive having to move the fences daily and set up the paddocks, but it does mean you can check 800 ewes in just 15min so that does offset the added labour time.”
The health and welfare of the ewes were also maintained despite being so heavily stocked. Mr Miller monitored faecal egg counts to check there weren’t going to be any problems and eggs counts didn’t go up.
However, he stresses the importance of soil testing for mineral and trace element status. “It’s vital you know your soil status and trace elements. We did conduct soil tests and tissue and blood samples as we have done bolus trials on farm before. This allowed us to make a informed decision as to whether we needed to supplement.
“If you have a deficiency it would only be exacerbated because of intensive grazing, so it’s vital to know what the grass is offering.”
Mr Miller is going to be all-grass wintering his ewes this year, but is moving to a four-day rotation rather than daily. “Sheep do seem content on a daily rotation and they get a fresh pick of grass, but a four-day rotation is less labour intensive.”
Mr Miller says the system has forced a changed in his thinking. “It made me talk about grass in dry matter terms instead of just talking about a field of grass. All-grass wintering is certainly a better way of rationing feed stocks as you know what you have got before you go in to the winter and you can ration effectively before feeding it all,” he says.
Results from six farms practicing All Grass Wintering 2012-13 |
|||||||||
|
Farm No. |
Sheep no. and breed |
Hectares |
Nov cover kg DM/ha |
Feb cover kg DM/ha |
Lambing cover kg DM/ha |
Scan % |
Supplement used (£ cost) |
Fencing Hrs /week |
Shifting sheep mins/day |
|
1 |
450 Mules, Texel X Mules, Dartmoor |
39 |
2650 |
1300 |
1200 |
146 |
None (£0) |
3.5 |
10 |
|
2 |
450 NZ Romney |
37 |
2300 |
1905 |
1715 |
193 |
3 tonnes forage on frosty days (£0.4) |
10 |
20 |
|
3 |
250 Mules |
23 |
2280 |
1640 |
N/A |
147 |
Silage offered but not taken. Feed blocks available (£5) |
 |  |
|
4 |
670 NZ Romney, Welsh Mules & Suffolk X Mules |
40 |
3020 |
1650 |
1850 |
160 |
Housed twin Mules- Feed blocks 8 tonnes forage used (£0.6) |
10 |
20 |
|
5 |
840 Kent Romney |
140 |
2240 |
1460 |
Not measured but below target |
160 |
Sheep housed 30t silage, 4t blocks, 12.9t ewe nuts (£8.50) |
10 |
20 |
|
6 Wales |
400 Easy Care |
40 |
3000 |
na |
Not measured but below target |
160 |
Small amount of hay offered but not taken (£1) |
7 |
5 |