Brassica forage crops provide low-cost feed

Friday 20.05.2022 , event , news

The cost of feed remains front of mind in decisions made on-farm this spring. Germinal’s Ben Wixey explains how brassica forage crops have a lot to offer as a valuable source of homegrown feed.

“Brassica crops can be very cost-effective, delivering a kilo of dry matter (DM) at a cost of 4-6p and some catch crops are ready to graze two months after sowing,” Ben says.

“They’re also a fantastic break crop before pasture renewal and offer flexible, all-year grazing.”

While brassicas can restore soil health in arable and grazing systems, it is recommended to leave a five-year break in between brassica crops to help minimise disease pressures.

Planting brassica forage crops now

“I recommend planting brassicas now for summer grazing,” says Ben. Hybrid brassicas like Redstart and Swift, and stubble turnips, are quick to establish.

By sowing brassicas now, you can be more confident about there being enough moisture in the ground than during the hotter summer months.

“By grazing livestock on brassicas over the summer, you can use grass pastures for cutting and fill your silage stores ahead of winter,” Ben adds.

Hybrid brassicas illustrate the flexibility of these fast-growing brassica forage crops. Often used for winter grazing, they can also be sown in May or early June and grazed just eight weeks later.

Yielding at 5-7.5 tonnes/ha with an ME of 10-13 and 16-17% protein, they offer a high energy, high protein alternative to grass.

Brassica crops for autumn/winter grazing

For crops such as kale and swede, you can drill a little later in the season for outwintering cattle, ewes or hoggets.

“Grazing over winter saves on the cost and labour required for housing livestock,” explains Ben. “After sowing, kale and swede are slower to establish, which usually indicates a good level of winter hardiness.”

Maris Kestrel kale is very winter hardy making it ideally suited for overwintering, with DM yields of 10-14 tonnes/ha.

Assistant farm manager at Harper Adams University Chris Ruffley achieved growth rates of 1.29 kg/day in his youngstock over winter using Maris Kestrel kale, far exceeding his target of 0.9-1.0 kg.

Suitable for outwintering cattle and sheep, Triumph swedes are often used specifically to support lamb and ewe condition.

Their high DM yield (9 t DM/ha) and ME value (12-14 MJ/kg DM) means they support high stocking rates on small areas of land. For guidance on growing swede, use our Triumph Swede Growers Guide.

How to select the right brassica crop

Crop typeSeed rate kg/ha (kg/acre)Sowing periodSowing to utilisation intervalUtilisation periodOut-wintering potential
Kale5.00-7.50 (2.00-3.00)May to late June20 weeksNovember to FebruaryHigh

Swede, natural

Swede, graded

2.50 (1.00)

0.50 (0.25)

Mid-May to late June25 weeksDecember to MarchHigh
Hybrid brassica, single graze5.00-7.50 (2.00-3.00)Mid-June to late August10 weeksSeptember to JanuaryHigh
Forage rape, single graze5.00-7.50 (2.00-3.00)May to late August8 weeksAugust to NovemberLimited
Multi-graze brassicas, hybrid brassicas/ grazing turnip5.00-7.50 (2.00-3.00)May to mid-June8 weeksMid-July to JanuaryModerate
Stubble turnip5.00 (2.00)March to August12 weeksAugust to DecemberLow

Most main crops of brassicas (swedes and kales) need to be sown by the end of June if they are wanted for grazing over the autumn and winter period.

Short term brassicas, like hybrid brassica or stubble turnips, should be drilled between May and the end of August to provide the quick catch crop needed to fill any shortfalls in forage later in the season.

For more information about sowing rates, fertiliser and management, please use the Brassica Growers’ Guide in our knowledge hub.

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