Sudden unrestricted access to a brassica forage crop can upset the balance of rumen microbes, resulting in poor animal performance, scouring and rumen acidosis, particularly in cattle. Start a feeding programme 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.
Most animals going onto a brassica crop have come off pasture. Pasture is usually of lower quality than brassicas, and the rumen contains different types of microbes than those needed to digest brassicas. If animals suddenly access brassicas, there can be a sudden overgrowth of the wrong types of microbes, which produce large quantities of acid (rumen acidosis). Reduce risk of rumen acidosis by offering animals other non-brassica feed (pasture, silage and/or hay) before moving animals onto crop. Pasture or supplements as part of the diet help maintain a normal rumen function. Feeding supplements before a new break of brassica reduces the risk of dominant, hungry animals gorging/ overconsuming brassica.