Oilseed crop can be grazed or ensiled, then harvested for seed
It won't compete yield-wise with alfalfa or triticale, but grazed or ensiled winter canola offers high nutritional value and digestibility its first year and can be harvested as an oilseed crop the following summer. So say University of Idaho (UI) experts studying its potential as a dual-use biennial crop.
“From an energy and protein standpoint, canola is an excellent forage,” says Carl Hunt, UI ruminant nutritionist.
Compared to high-quality alfalfa's typical 29% ADF, canola's is below 18%, Hunt says. That extremely low fiber content results in an extraordinarily high relative feed value compared to other forages, he adds. Canola's crude protein content measures about 20-21%, comparable to that of alfalfa.
The crop has the upper hand in digestibility, which reaches 90%; high-quality alfalfa's digestibility normally is at 80-85%.
But, as with alfalfa, canola can cause bloat. That can be controlled by adding more hay to the diet.
Although some fear a reduction in seed production, research by Clark Neely, graduate student in the UI canola and mustard breeding program, shows only minor seed yield loss.
“I think once we figure out when the optimal time is to harvest it, I don't see that there'd be much of a decrease in seed yield,” he says.
Jerry Hedges had similar findings while fall-grazing cattle on winter canola. Hedges is a canola grower and seed dealer in Vici, OK.
“It does not in any way harm production of the canola for the cattle to eat the top growth off of it in the fall,” he says. “But you have to take them off of it early in the spring before it breaks dormancy.”
Although feeding trials won't start until next summer, Neely is optimistic that canola is palatable after having witnessed sheep devour it freshly chopped. “The first day or two they kind of ignored it,” he says, “but once they found out what it was, they ate it like candy.”
Cattle gained up to 2.99 lbs/day in one reported instance, which compares to about 2 lbs/day for grazing wheat and triticale, says Vic Martin, Kansas State University agronomist at the Hutchinson experiment station.
Another advantage to grazing canola, Martin adds, is that it allows for higher stocking rates. One rancher stocked two 500-lb cattle per acre, nearly double the stocking rate of wheat for fall grazing.
“But, then again, grazing canola is intense and quick because you're not going to worry about grazing it again in the spring,” he notes. The crop can be grazed 60-80 days if planted seven to eight weeks before the first frost date, which is a week or two earlier than that planted for seed, Martin says. Seeding rates, the same for seed and grazed canola, should be at 4.5-5 lbs/acre.
Grazing can start four to six weeks after planting.
Ensiled canola may be preferred on Idaho's large-scale dairies, Neely adds.
Its biggest obstacle: low yields. Irrigated canola yielded up to 3.9 tons of dry matter per acre in Neely's study. Competing forages in similar growing regions of northern Idaho normally bring 7 tons/acre. In southern Idaho, where growing seasons are longer, forage yield of irrigated canola may even match conventional forages, Neely adds.
In time, he sees canola's yield disadvantage being solved with future field trials. “I think once we start fine-tuning some things, and if there's some more research done on it, there's potential to boost yield. We're just scratching the surface.”