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Hemp silage trials show high protein, energy levels

Posted on August 24, 2000

Consort, Alberta — When Health Canada officials told Curtis Weekes they needed a sample of the end product of hemp silage, he was tempted to send it.

“Then somebody realized what that was (cattle manure) and told me it was not necessary,” said the Alberta Agriculture crop specialist.

That incident was an example of the legal requirements Alberta researchers encountered when they applied to grow hemp for a silage project.

A special research licence was obtained to grow low THC hemp and all traces of the plant were destroyed after the study.

“We had to pay for a drug test,” said Weekes during a field day near Consort where the hemp was grown.

Tests showed it was well below the legal limit for THC, the hallucinogen found in greater abundance in marijuana, a cousin of hemp.

Alberta’s Special Areas consist of five million acres of shortgrass prairie in southeast-central Alberta and have been administered by a provincially appointed board since 1938. Farmers there thought the leafy, fast-growing hemp could work if conditions were right. Barley leaf diseases are becoming a greater problem so farmers have been experimenting in recent years with crop alternatives.

When researchers scanned previous studies for comparative purposes, they discovered hemp silage had never been tried. Some people have fed hemp seed and stalks after the fibre was removed, but no one had attempted a silage crop.

Results from the summer of 1999 were promising.

The project was carried out at Ron Letniak’s farm near Consort.

Last year’s trial was successful because the right amounts of rain fell. This year the project has been a failure. Neither the hemp nor the control crop of barley grew because of drought in southeastern Alberta.

In 1999, 10 acres of hemp were grown next to 10 acres of barley and oat silage as a control.

Harvest dilemma

Researchers were not sure when to cut the hemp and opted for the early flowering stage.

It was a challenge to cut the silage and put it through the auger because the stems got tangled. Some stems were no bigger than a man’s little finger, while others were as big as a wrist.

The crops were fed to two groups of heifers. Health Canada did not want animals destined for slaughter used in the trial.

The cattle liked both feeds, and weight gains were equal.

“There was absolutely no difference,” said Weekes.

However, researchers did notice that cattle licked the hemp feed bunk clean while some barley silage was always left over.

Hemp proved to be high in protein at 19 percent, high in energy and had good dry matter production. Acid detergent fibre was much higher than barley-oat silage at nearly 41 percent compared to 28.2 percent. ADF is the indigestible part of the plant. Calcium and phosphorus were also higher in hemp.

Further trials and research data are required to gain a licence to grow hemp for feed.

Copyright © 2000, The Western Producer. All rights reserved.