Cover crops for additional forage

The strategic use of cover crops can help plug gaps in forage supply. Learn about the types of cover crops that are suitable to feed to livestock.

Cover crops can be grown for short-term grazing fodder for sheep or cattle. When planning cover crops for forage, take a whole-farm approach and consider:

• The total feed requirements for the livestock on your farm
• How feed requirements are met under the current system
• How much feed is potentially needed from cover crops
• Which cover crops are suitable for forage and your system

Cover crops for forage

• Grasses and cereals, such as oats, rye and rye-grass
• Brassicas, including kale, grazing turnips, mustards, radishes, stubble turnips and rape/kale hybrids, are generally suitable for feeding to all classes of beef cattle and sheep
• Under appropriate field conditions, non-lactating, spring-calving suckler cows can be outwintered on kale and stubble turnip systems with no concerns in relation to liveweight or condition loss
• To avoid the risk of calving in an unsuitable environment, cows should not be grazed on brassicas in late pregnancy
• In late pregnancy, ewes fed on root crops will generally need additional protein to ensure their nutritional requirements are met
• Swedes are only recommended for cattle with fully mature teeth and are not suitable for ‘broken-mouthed’ sheep
• Fodder beet, although technically not a brassica, can also be grazed in situ or lifted and fed to livestock
• Chicory is a deep-rooted herb (delivering soil structure benefits) and is better suited to longer-term use, especially where grazing is of interest
• Legumes (such as sainfoin, vetch and clovers) can be grazed with care
• White clover has higher digestibility, protein and mineral content than grass (unlike grass, it retains its digestibility through continual renewal of leaves and little stem development)
• Forage gaps could also be filled by feeding silage or hay, but this will increase feed costs

Be aware that some cover crop species are potentially toxic to livestock. 

• Buckwheat can have a toxic effect (photosensitisation), especially in high concentrations
• Some linseed releases cyanide when grazed, which can be toxic to animals
• As red clover has high levels of phytoestrogens it can cause fertility issues (do not feed it to breeding ewes six weeks before and after tupping)

If in doubt, consult your vet, especially before grazing unfamiliar covers.

Effective grazing management

Well-managed livestock can do a fantastic job of reducing the bulk of a cover crop and start breaking down organic matter (and adding to it, via manure).

By breaking down organic matter, livestock help balance C:N ratios and make the nutrients available to the following crop quicker.

They also provide income from the grazing, either as meat to sell or through grazing payments, as well as giving the grazier’s grass a rest from grazing.

Many favour grazing by sheep to terminate cover crops (the ‘golden hoof’ treatment). Cattle are also used, although their extra weight can increase poaching risks, particularly on heavy soils.

Top tips

• Monitor soil and weather to ensure conditions are suitable (minimise runoff risks)
• Grazing should be ‘fleet of foot’, particularly on heavy soils
• Introduce livestock slowly to get them used to the cover crop
• Consider strip grazing (if grazed areas are back-fenced, compaction can be reduced, which will benefit the establishment of any subsequent grass leys)
• When grazing brassica (which have a low fibre content) provide access to an alternative roughage source, such as haylage or straw
• Consider leaving haylage bales in place after sowing the cover crop to reduce compaction risks associated with transportation
• Match feed to suit mob-grazing requirements
• Provide constant access to water, ideally through a portable trough system, for ease of use and to reduce soil compaction

Grazing winter cover crops can lead to some agronomic issues, such as soil compaction and leaching of nitrogen deposited in urine (especially in adverse weather conditions).

Mitigate such risks by having a ‘back-up’ field nearby, to move livestock to, if ground conditions worsen.

Food safety standards do not allow cover crops to be grazed immediately prior to growing leafy salads, so green manures should be flail-mown before being cultivated.

If livestock are not on the farm, consider working with graziers or neighbouring farmers who could supply the stock, infrastructure and expertise.

Forming a good relationship is key to ensure both parties benefit. It will help you communicate easily and honestly about the removal date, bad-weather strategies, the residual crop target and the species mixture.

In fields where the public have a statutory right of access (or have been given access by the landowner), it is good practice to display signs to indicate the presence of livestock.