With Prairie farmers looking at $10 to $12 per bushel canola this year, few would consider it an economic crop for feeding cattle. But, if someday, you do end up with a stand that doesn’t have value as an oilseed, it can always be used for grazing or silage.
According to Agriculture Canada, producers could seed about 18.5 million acres of canola in 2011. However due to a wet fall last year, an anticipated cool, wet spring and forecasted wet summer, the weather could stack up against some fields this year. And any canola that doesn’t make grade could be turned into nutritious forage for cattle.
For a minute, let’s forget canola as a popular high-yielding oilseed, but as whole green plants, which can be incorporated into the forage portion of any well-balanced cattle diet. It can be easily grazed, cut as green-feed, or hay or fermented as silage for cattle.
Producers whom have already fed canola as forage to their cattle say at its best quality it is comparable to good quality alfalfa-grass forage. A backup of analytical tests on canola harvested during mid-flower to early pod stages reflect: a crude protein content as high as 18 to 20 per cent (dm, basis), a high total digestible nutrient value (TDN) of 63 to 65 per cent, ADF fiber of 28 to 30 per cent, with calcium and phosphorus levels at 1.3 to 1.5 per cent and 0.4 per cent respectively.
Regrettably, many oilseed fields destined for cattle feed are of significant lower quality — crops stressed or damaged in some way. For instance, hailed-out canola can still be salvaged for pasture or for hay or silage, but may yield only about nine to 10 per cent protein and have a depressed TDN energy value of 50 to 55 per cent.
Such a wide range of canola forage quality from poor to excellent shouldn’t deter anyone from feeding canola as forage to cattle. However, before formulating it into beef diets, field samples should be collected and sent to a reputable laboratory for a general forage test. A requested analysis should include dry matter, crude protein, TDN, NDF and ADF fibre analyses, calcium, phosphorus, potassium and magnesium content. It might also be a good idea to ask for a sulphur and nitrate test.
The sulphur test is of particular importance. Canola tends to accumulate sulphurous compounds from soil and frequently exceeds the safe threshold of 0.4 per cent on a dry matter basis for beef cattle. High dietary sulphur kills the B-vitamin-producing bacteria in the animal’s rumen and therefore makes afflicted cattle susceptible to a specific brain disorder, polioencephalomalacia (PEM — cerebrocortical necrosis).
In addition, high sulphur intakes are linked to induced copper deficiencies in cattle. Sulphur combines with copper in the gut of the animal or in its tissue and renders copper biologically unavailable. To reduce the chances of PEM or a marginal copper deficiency, many ruminant specialists suggest canola provided as pasture, hay or silage should make up no more than 50 per cent of the dry matter intake of total feed consumed by cattle.
Likewise, an accurate nitrate test of canola forage samples, particularly from stressed and damaged canola crops (re: drought, hailed or frosted) will help avoid serious nitrate poisoning in cattle. Abortions and high mortalities are common among pregnant cattle poisoned by forage nitrates. Nursing beef cattle that consume sub-lethal nitrate levels suffer from reduced appetite, and poor milk production, while young livestock have poor health and growth performance.
Forages analyzed for nitrate levels are commonly reported as nitrate (NO3) or nitrate nitrogen (NO3N). Beef cattle can safely consume a diet containing nitrates that are below 0.5 per cent nitrate (NO3) or below 0.12 per cent nitrate nitrogen (NO3N) on a dry matter basis.
Aside from these darker nutritional aspects of canola forage, it’s a good idea to double check any canola used for feed was not sprayed with any pesticide or chemicals not to be grazed or fed to cattle. Failure to heed this warning could have dire consequences to the health and performance of the cattle as well as open the possibility of unsaleable meat residues.
GOOD FIT FOR CATTLE
Luckily, after a general and the latter two analyses of canola feed give a clean bill of health, canola can be used in any capacity as part of the forages fed to cattle.
First, many people interested in grazing canola as a means of salvaging a damaged crop brought on by drought, hail or even an early frost. Others are interested in placing cattle on canola fields believed to have poor seed set, slow vegetative growth during the summer, or poor oilseed yield in the fall. Energy and protein intake and content of these crops fed to cattle could be lower than expected. For these primary dietary reasons alone, it is often recommended that other traditional forages, particularly of medium quality be supplemented to cattle before letting them graze canola fields.
Keep in mind undamaged and good growing canola fields can also be grazed by cattle. The University of Idaho (2010) took a different approach and let a herd of beef cattle graze fall-seeded canola to be harvested in the following year. They found putting cattle on the crop could be started four to six weeks after planting. Because the young canola plants have such low fibre content, they tend to have much higher digestibility than even high-quality alfalfa. As a result, these researchers advised bloat is always a potential problem, but could be easily rectified by supplementing regular grass hay into the diet.
On a similar note, canola can also be made into hay. To maximize yield and potential nutritional value, canola should be cut at late flowering. After cutting, the crop should be crimped or conditioned to release trapped moisture from hollow stems and reduce curing time, before making it into bales. It usually takes a day or so longer (four to six days) for canola to dry to 16 to 18 per cent moisture compared to other conventional hay crops. Well-cured canola hay is much like alfalfa-grass hay and is very palatable to cattle.
People living in the wetter parts of the Prairies might find they don’t have the luxury of an extra day to dry canola sufficiently to make good-quality hay. Instead, ensiling canola like a cereal crop might be a better option for them. Silage-making, producers should make sure canola’s hollow stems are crushed in order to help it wilt to 60 to 65 per cent moisture in the field, before unloading and packing in a bunker. It might be also layered with another crop — a combination of 1/3 canola to 2/3 barley silage, for example — to ensure rapid and complete fermentation and to reduce canola’s overall
sulphur and nitrate content.
Whether it’s made into silage, put up as dried hay or grazed, canola can be nutritious and palatable feed for cattle. In all feed forms canola can easily be worked into cattle rations.
Following the general rule that canola forage should not make up more than 50 per cent of the dry matter intake of the animal, consider the following five dietary examples for over-wintered mid-to late-gestation mature beef cows in up in a total mixed ration (TMR):
17 kg of canola silage, 8 kg of alfalfa-grass hay, and 2 to 4 oz.
of 14:14 beef mineral and 1- oz. Salt.
10 kg of canola silage, 5 kg of grass hay, 5 kg of barley straw, 1.0 kg of barley and 4 oz. of 14:14 beef mineral and 1- oz. of salt.
15 kg canola silage, 6 kg of barley straw, 3 kg of barley, 4 oz. of 2:1 beef mineral and 1- oz. Salt.
6kg of canola hay, 8 kg of al
falfa hay and a 2 to 4 oz of 14:14 beef mineral and 1- oz. Salt.
7 kg of canola hay, 6 kg of mixed grass hay, 2 kg of 14 per cent cow-calf pellets (with minerals and vitamins).
As with any new or uncommon feed, canola forage might be introduced slowly by replacing part of a more conventional diet over a week or more. Cattle should be watched over the next few days assuring good acceptance of the new rations. Given the darker nature of some canola forage (re: sulphur and nitrates), look for cattle behaving abnormally. Otherwise, continue to incorporate canola forage into their diets as any other type of forage.
If it isn’t grazed, canola should be cut at the proper growth stage to be put up as high quality hay or silage. Despite some nutritional health risks, a proper forage analysis should guide producers into how much canola can be formulated into a diet. Eventually, most cattle should accept these diets, turning a crop failure into a feeding success.
PeterVittiisanindependentlivestock nutritionistandconsultantbasedinWinnipeg. Toreachhimcall204-254-7497orbyemailat [email protected]
Canola “it can be easily grazed, cut as green-feed, or hay or fermented as silage for cattle.”