A new generation of forage rape/kale hybrids has been growing in popularity as a source of feed among livestock farmers over recent years. These hybrid brassicas are well-suited to Irish conditions. The forage rape genes in the hybrid variety give it the ability to grow rapidly, while the kale genes provide good winter hardiness.

Redstart is an example of one of these hybrid brassicas and it is mainly used as a high-energy protein crop for out-wintering cattle and sheep.

However, the crop can also be baled or zero-grazed, if required, and fed over the winter.

Hybrid brassicas are well-suited to Irish conditions

This was done in a number of cases in 2018, when many tillage farmers grew the crop for the first time in response to a shortage of fodder.

One of the key advantages of growing redstart is that, with proper management, it can be used for multiple grazings. This depends on a number of factors including sowing date, fertilisation and growing year.

Good seed to soil contact is essential so aim to roll after sowing the crop.

Sowing

We caught up with Jim Gibbons, sales and production manager with Germinal, who explained that redstart is generally sown between June and August and will be ready for grazing 90 to 110 days after sowing.

Redstart seed is relatively inexpensive at around €10/kg and can be established using a number of methods. Sowing earlier is possible, but increases the risk that the seed will bolt due to stresses, explains Jim.

It is important to achieve good seed-to-soil contact in order to get good establishment

Like any crop, it is important to achieve good seed-to-soil contact in order to get good establishment. However, as redstart seeds are so small, this point is especially important.

Establishment methods range from ploughing, tilling and sowing to discing and broadcasting the seed. Ensure you have a fine, firm and level seed bed before sowing.

The crop should be sown at around 7.5kg/ha to 8.5kg/ha at a depth of 10mm. Seeding rates are generally higher if broadcast to account for losses.

Aim to sow in good conditions, when it is warm and when there is likely to be ample moisture for germination. Redstart can also be included in a grass seed mixture at 1.8kg/ha to 3.7kg/ha. Roll after sowing if conditions permit.

Aim to sow in good conditions, when it is warm and when there is likely to be ample moisture for germination

Where sowing into grass ley or even stubbles with volunteer growth, aim to treat the field with glyphosate at least six weeks in advance. This will help to suppress weeds and volunteers when your crop is establishing.

A follow-up application of a graminicide may be required to knock out any volunteer cereals missed. Remember that all farmers who apply any pesticide (herbicide, insecticide and fungicide) must be registered as a professional user and use a fully tested sprayer.

Pests

Pests generally are not a big problem with redstart, due mainly to its quick establishment and favourable conditions when sowing.

Where slugs are an issue, an application of slug pellets may be required but populations should be monitored closely before doing this. Grazing by pigeons could also be problematic when the crop is establishing.

Livestock often need to be supplemented with forage and minerals when being fed hybrid brassicas.

Nutrition

Hybrid brassicas can be nutrient-hungry. It is important to soil test your planned location for the crop around eight weeks before sowing. This will give you a good idea of the nutrient status of the land and the pH level.

This will give you time to apply lime if required and also determine the crop’s fertiliser requirements. Table 1 outlines the suggested nutritional requirements of hybrid brassicas.

A split nitrogen dressing is advised. Spread half of your required nitrogen at sowing, along with phosphorus and potassium, and the other half approximately three weeks later.

Comment: Feeding restart

Hybrid brassica is a high-energy and high-protein fodder crop designed to be grazed in-situ. The hybrid varieties are a cross between kale and rape. Protein levels of 18% to 20% are common, making it an ideal crop for young, growing cattle. Energy levels are high, similar to midsummer grass.

While it is possible to ensile these fodder crops, the majority are grazed so site selection is critical. Most farmers will feed some form of fibre along with the crop, whether that’s straw, silage or hay although trials have shown that youngstock can successfully graze 100% fodder hybrid rape.