Faced with rising purchased feed costs and potential winter forage shortages due to a challenging silage season, brassica crops can provide a nutritious, cost-effective feed option for farmers this winter.

Brassicas offer high yields of quality forage, consistently achieving between 10.5-13MJ/kg dry matter of metabolisable energy (ME) and 16-24% protein, helping to stretch silage stocks and offer a suitable alternative to grass during slow growing winter months. For those who may also be lacking indoor space, out-wintering stock on brassicas could prove beneficial.

Alex Law, forage product manager at Carr’s Billington, said these crops also boost soil structure, but for maximum benefit to livestock, it’s important to consider them as part of a wider winter feeding plan.

“Winter brassicas can be used really effectively as a break crop prior to re-seeding, helping to reduce weed, pest and disease burdens, and create better soil conditions and cleaner seedbeds for establishing new grass swards,” he pointed out.

Depending on the individual farm’s requirements, there are a number of different brassica crops to choose from.

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Kale can produce double the dry matter per hectare compared to forage rape and stubble turnips, but it has a large nutrient requirement so needs higher inputs of nitrogen fertiliser and water and takes longer to grow. Forage rape and stubble turnips are often phrased as ‘catch crops’ because they are fast-growing, ready to graze in three to four months from sowing and can be grown between continuous plantings of a main crop.

Mr Law added that it’s important to remember the rate of establishment will vary depending on geographical location, fertility and weather conditions, so it’s worth seeking advice beforehand on what crops will best suit your land and system.

Although these crops can provide cost savings and convenience to farmers as they reduce the requirement of additional forage, they need to be considered as part of an overall winter-feeding programme.

“Forage brassicas lack structural fibre, therefore providing an ad-lib source of coarse fibre from silage, hay or straw will help to maintain rumen function and prevent acidosis and bloat. Additional mineral supplementation will also be required as forage crops tend to be deficient in minerals, especially iodine and selenium,” Mr Law added.

Strip grazing with an electric fence, which is moved daily, provides a long narrow section of brassicas, helping to ensure all animals have access to a small, but fresh, area of crop. If incorporating brassicas into the diet, beef and sheep should receive a maximum of 70% of dietary dry matter from brassicas, whereas milking cows should receive no more than 30% to prevent milk taint.

Successful use of brassicas

Tom Stobart farms around 700 ha of fell land in a HLS scheme and 140ha of lowland, near Croglin, in Cumbria. The fell ground is used for his 400 breeding ewes, with 250 Wagyu cross cattle grazed on the lowlands.

For the past 10 years, he has been using a range of different winter brassicas, including stubble turnips, hybrid kales, Caledonian kale and fodder beat to out-winter his cattle and sheep.

“As we’re on quite dry land, it’s favoured to out-wintering and we lack the space to bring all livestock inside. We can grow a lot of grass in the summer, and we get fairly hard winters, meaning we often have a shortfall of forage, so the brassicas are a really good buffer to over winter stock,” he said.

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“We’ve tried a number of different crops in the past, but we tend to just use kale as we find this easier and it also helps to break any pest cycles before a re-seed.”

As well as the brassicas, livestock also have access to silage bales in the field to ensure full nutritional needs are met. One of the greatest benefits Mr Stobart has found when incorporating brassicas into his rotation is that it helps to save on labour time and costs.

“Out-wintering the livestock means that we’re not having to spend time scraping and mucking out sheds. We also position our wrapped silage bales in the field once the brassicas have been planted, before the winter season comes, to avoid bringing heavy machinery into the field over winter which could damage the soil.

“There’s obviously a cost to it because you have to take land out of production and re-seed, but the total cost is far less than purchased feed. Particularly as recent poor harvests have pushed feed costs higher and higher.”

As the farm is quite mineral deficient, especially in iodine, they bolus all cattle and sheep to make sure they’re sustained throughout the winter months.

“We’ve found that brassicas really help keep the livestock, particularly the Wagyu cross beef, ticking over until they go back onto grass in the summer. Using this in conjunction with silage and added nutrients helps us get our livestock through challenging winters, while keeping costs and labour requirements low,” Mr Stobart added.