Ensiling Canola
Although canola silage is not a typical livestock feed in Manitoba, in other parts of the world canola, and for that matter, other brassica species (i.e. turnips and kale) are used extensively in livestock operations. Typically, we may see canola used to feed livestock in Manitoba during drought years where feed shortage is a problem. However, there are potential problems affecting cattle that must be considered before feeding canola silage.
What varieties work best for silage?
Canola is used for livestock feed in many parts of the world. In fact, special forage varieties have been developed for certain climates. If your neighbor is talking about the dangers of feeding canola because of glucosinolates, don’t be concerned. Glucosinolates are relevant only if feeding the traditional rapeseed. They are the compounds that give brassica species its bitter taste. They are typically associated more with poor production in swine and poultry (e.g. lower weight gain, egg production, etc). However, ruminant livestock can tolerate diets containing low levels of glucosinolates.
What stage should you harvest for hay or silage?
For both hay and silage crops, the best yields and quality are achieved if the crop is cut between the early podding stage (just after the flowers have dropped) up to when the lower leaves are starting to drop. Keep in mind that quality (energy and protein) will be higher if cut at the earlier stage. Canola cut near maturity has a feed value similar to cereal straw, and becomes quite unpalatable.
Canola Hay
Just like any other hay crop, recommendations are to allow the swath to cure to 16%-18% moisture before baling. However, since canola is typically at 75% to 80% moisture when cut at the optimum forage stage, it takes time to wilt them down to proper baling levels. The thick stems and succulent leaves also delay dry down periods. It may take up to a week for the swath to dry enough for baling. Using a mower-conditioner (often called “crimping”) will quicken the drying process, however, canola is prone to ‘shattering’, and as a result, this equipment may increase leaf and pod losses, especially if cut too late. Crimped hay also takes longer to dry down if wet from rain. Some have suggested baling canola with dew on it to reduce leaf and pod loss. You may see the swathes turn black as it is curing, but studies have shown this does not affect palatability.
Canola Silage
Ensiling is probably the best way to utilize canola for feed. Higher moisture levels and earlier processing dates minimize leaf and quality losses. Like alfalfa and corn silage crops, recommendations are to allow the swath to wilt to 60-65% moisture before ensiling. There are few things you can do to improve the ensiling of canola. If you ensiled at 70% or greater moisture, it is best to use horizontal storage to reduce seepage and ensiling problems. Secondly, some producers have had positive results by layering different silage crops in the bunker (i.e. alternating layers of canola and cereals cut for silage). The difference in moisture between two crops helps to reduce seepage problems and offers the opportunity to mix the layers when feeding the silage. Thirdly, since oilseed crops are low in soluble carbohydrates, the addition of bacterial silage inoculants may be beneficial when ensiling these crops.
Nutritive values
Canola can be fed to livestock provided certain precautions are taken. While these crops make palatable feed, it may take one or two days for cattle to become accustomed to their taste. Studies suggest canola hay or silage should comprise no more than 50 to 60% of total daily feed intake. Higher portions of canola can have negative affects on herd health. In particular, canola silage may contain high levels of sulfur and nitrates. Some producers have noticed that cattle tend to develop scours when fed canola hay or silage as the only source of roughage. Livestock would adjust to canola forage by mixing the feed rations over a 7-10 day period. This adjustment helps prevent bloating and other diseases. Generally speaking, canola silage has good feed quality, with crude protein levels between 12-14%, sometimes as high as 16%, with total digestible nutrients (TDN) ranging from 55% to 60%.
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