1. Don’t Allow Stock Sudden Unrestricted Access to a Brassica Crop
Sudden access can upset the balance of rumen microbes, resulting in poor animal performance, scouring and acidosis. Start by grazing the crop for no more than 1-2 hours per day, building up to a maximum allowance over at least 7-10 days. Allow rumen microbes time to adjust to the high quality forage.
2. Feed Extra Fibre Prior to and While Grazing Brassica Crops
Forage crops are highly digestible, and don’t contain much ‘effective fibre’, the sort of fibre that makes animals chew. Feeding extra effective fibre means:
• More chewing and increased salivation, which helps maintain rumen pH and as a result there will be fewer digestive upsets.
• Slower flow of feed through the rumen and gut, with a more effective rumen fermentation.
• Increased cud chewing and more effective digestion. Extra fibre should be given prior to and throughout the brassica feeding period, through access to pasture, hay or straw. This will help to prevent gorging, help rumen microbes adjust to the feed and help to maintain normal rumen function. It is suggested that 20-30% of the diet is fed as hay, straw, or runoff pasture.
3. Feed Brassicas as Part of a Balanced Diet
Animal performance on brassicas is best when crops are fed strategically as part of a balanced diet. For example, the high protein and energy of brassicas complements stalky summer ryegrasses which can be deficient in energy and protein, or whole-crop cereal and maize silages which are low in protein. Feed dry stock no more than 70-80% of the diet as brassica, and feed lactating dairy cows no more than 33% of their diet as brassica if milk is being sent to the factory.
4. At all Times Give Animals Access to Water when Grazing a Brassica Crop
Although the water content of brassicas is high, it is recommended that animals have access to fresh water at all times as a limited water intake will cause an animal’s dry matter intake to decline.
5. Recognise Potential for Stock Health Problems
Feeding brassicas can sometimes be associated with animal health problems. Risk can often be avoided by good agronomic and grazing management.