Source: Manitoba Agriculture, Food and Rural Initiatives
Straw is a good alternative feed for beef cows when it is properly supplemented. See the beef section on the Manitoba Agriculture website for sample rations. On average, cereal straws contain 4% protein and about 45% TDN. Oats is considered the most palatable followed by barley and then wheat. The TDN of rye and buckwheat straw is only 41-41%.
Legume straws tend to be higher in protein (7-8% CP) but have a similar TDN compared to cereal straw. This is due to varying levels of seed which may be left in the straw. Pulse straws, such as peas, lentils and chickpeas, are palatable once animals become accustomed to the taste. Legume straws contain much higher levels of calcium and phosphorus than do cereal straws. Soybean straw has little or no value as a feed due to its extremely high fibre content.
Grass straws are considered more palatable than cereal straws. Its nutrient value is similar to cereal straw. Millet straw is often the best quality straw with protein and TDN levels of 6% and 50%, respectively. Flax and canola straw have little, or no, feed value. However, some recent feed analysis reports from around the province show that canola straw may have better than expected feed value.
Canola is a difficult crop to harvest and store. It can be harvested as either hay or silage. Spoilage may be high if harvested as a hay because of difficulties associated with drying down. For successful ensiling, the moisture content must be less than 65% or a very poor fermentation and/or high seepage losses may result. Canola forage will contain about 12% protein and 55% TDN.
Corn stover refers to the corn plant after the grain is removed and includes leaves, cobs and stalks. Samples from the Southeast region of Manitoba show a variable nutrient content with protein levels ranging from 5-8.4% CP and 49-57% TDN. The hollow stems can lead to difficulties in drying the plant down to levels necessary to avoid spoilage.
Weeds can have good feed value if harvested at a relatively young stage. When kochia is harvested prior to flowering, it has a nutrient value similar to alfalfa. It is a palatable forage but, due to its high level of mineral salts, is also a powerful laxative. Kochia should not make up more than 50% of the diet dry matter. Quackgrass and other grass-type weeds have a nutrient value similar to tame grasses with about 8% protein and 52% TDN.
Some of the potential drawbacks to feeding weeds include:
· Weeds are prone to accumulate nitrates
· Weed seeds survive their passage through the digestive tract with varying degrees of viability (15-98%); feeding weed seeds and spreading the resulting manure on fields may spread a weed problem
· Some weeds are poisonous
· Some weeds may affect product quality
Cattails and Bulrushes
When cattails are harvested young, they have a slightly higher value than cereal straw with about 6% protein and 50% TDN. Mature cattails have no feed value. Although feed tests show bulrushes are similar to cattails in terms of protein and TDN, bulrushes are very fibrous and are not consumed readily by cattle.