Released on December 7, 2004Many acres of swathed crops are still lying on the ground, and cattle producers are wondering if it is safe to let cattle graze those swaths. Saskatchewan Agriculture, Food and Rural Revitalization recommends exercising caution when letting cattle graze mature swaths.
Normally, crops used for swath grazing are cut in the early - to mid-dough stages of development when the crops are green, leafy and contain good levels of protein and energy. However, when a crop has matured and is swathed for harvest, it is comprised essentially of grain and straw and needs to be treated in an entirely different manner.
A cow feeding on a swathed, mature crop will consume about 15 lb. of straw and 15 lb. of grain daily. Under these conditions, there is a high risk that the cow will develop grain overload, free gas bloat or acidosis. The ingestion of high amounts of grain also fosters the development of lactic acid and acid-tolerant bacteria in the stomach. This situation can damage the rumen wall, allowing bacteria to enter the blood stream and form liver abscesses. Cattle with more severe cases of grain overload experience abdominal pain and often lie down.
Due to the higher risk of acidosis, the best option for using unharvested wheat, durum and rye crops is to thresh the swaths, then coarsely grind or roll the grain and feed it according to acceptable recommendations. Processing the grain increases its digestibility by 20 per cent or more. Do not feed more than six pounds of wheat (4.5 lb. of durum) to a mature cow daily.
Oats, because of higher fibre content, can be fed at higher levels. It is usually not economical to process oats as the digestibility is only increased by three to five per cent; whereas the digestibility of barley is increased by 20 per cent or more. If feeding more than eight or nine pounds of barley or oats per mature cow per day, divide the grain into two equal portions. Feed one portion in the morning and the other later in the day.
Another option for salvaging the grain is to bale the unthreshed swaths, but it is not advisable to give cattle free access to these bales in a bale feeder as the cattle may selectively eat the grain, which can lead to grain overload. Instead use a bale processor, tub grinder or bale shredder to blend the swath-bales in a 50:50 mix with good quality hay bales. This practice reduces the total amount of grain intake and ensures that there is a source of protein in the ration.
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|Agriculture Knowledge Centre|
Agriculture, Food and Rural Revitalization