February is usually the month I start to receive telephone calls from farmers that their multi-graze brassica crops are not looking like they are going to be high-yielding and of good enough quality to be locked up for winter.

Why the crops are not looking as good can be due to a variety of reasons:

• Disease, 
• Insect pressure,
• Waterlogging,
• Drought,
• Overgrazing,
• Treading damage,
• Poor crop establishment.

Whatever the cause, a farmer needs to determine if it is worth taking the crop into the winter or looking at other options to sow in that paddock. Consider the economic viability of carrying the crop through, including what the feed was budgeted for, how important the crop is to the wider system, and what the now expected yield is.

Raphnobrassica has a basic rule of thumb that if there are less than 10 plants per m² then it is most likely worthwhile spraying the crop out and sowing a winter feed option. If there are between 10 to 15 plants per m², consider under-sowing a winter feed.

With more than 15 plants, the Raphnobrassica is well-established and can be locked up for winter. For other brassica varieties, a visual assessment is necessary. Contact your local PGG Wrightson Technical Field Representative who can help you decide whether to go ahead with the brassica crop or choose another winter feed.

If a crop needs drilling, the two most common crop types are annual ryegrass and oats. The discussion around which option is the best focuses firstly on how well the feed fits into the existing system. Oats match relatively closely with what is achieved with a stored brassica; it provides a single graze bulk of feed in mid to late winter. After grazing, it is unlikely to provide substantial regrowth and the paddock will be ready to prepare for a spring-sown crop.

Annual ryegrass provides a similar amount of dry matter over the same period as a brassica but requires multiple grazings to achieve this. Though the same result of having a bulk of feed to hold stock on will not be achieved, the ryegrass can be grazed further into spring if the plan is to sow the next crop in late spring.

Be aware that if sowing an annual ryegrass, it is easy to fall into the trap of not spraying it out early enough. This is because it is in high production when spraying out is necessary when following with crops such as permanent pasture, lucerne, or chicory. To avoid this issue, consider following ryegrass with another brassica or a summer fallow.

Contact your local PGG Wrightson Technical Field Representative to come and assess your brassica crops and help plan your winter feed programme.