Time is now to finish grazing brassicas

Wednesday 19.02.2020 , News

Most farms are now coming towards the end of their brassica crop, but for those farms with a larger area still to graze, there are some important considerations.

The advice is to aim to have finished grazing your brassica crop of Kale, Redstart or Forage Rape before the end of February.

Forage brassicas contain SMCO (S–methyl cysteine sulphoxide) which is generally not an issue for animals once they are introduced to the crop slowly and have a fibre source which contributes 30% of the total diet. This is usually in the form of silage or straw. However, as the season progresses, forage crops will mature and begin to flower, and once this occurs brassica crops will present a higher risk to animals as they have the greatest concentration of SMCOs at this time. Excess levels of SMCO’s can lead to anaemia, appetite loss and animals are also likely to develop a condition known as “Redwater”. Therefore, it is very important to note that Brassicas generally flower in late February.

Signs of Redwater

Some obvious signs of Redwater include:

  • Urine colour becoming dark brown to red.
  • Animal may appear weaker with a decreased appetite.
  • Pale or yellow mucous membranes.

If Redwater is observed, affected animals should be immediately removed from the brassica crop and offered a silage or hay–based diet (with no brassica) to reduce SMCO build up in the bloodstream. Increase fibre supplementation to the remainder of the herd’s diet and consult with your vet immediately.

It is important to monitor your brassica crops for flowering and aim to have them grazed before it occurs. Do not introduce stock to a brassica crop for the first time now; only graze the crop with stock that have been turned out on it for the last while as they will have greater tolerance to SMCO’s.