Weeds for Livestock Feed

By Brenda Frick, Ph.D.

At the recent “Going Organic” conference in Calgary AB, Brewster Kneen suggested that we live in a society that is “profoundly ungrateful”. I feel that this attitude characterizes our relationships with the plants we refer to as weeds. In this season of herbicide ads it is perhaps time to consider a few of the reasons to be grateful for weeds. Weeds can play a major role in livestock operations.

Most weeds are palatable and of acceptable quality for animal feed if they are grazed or cut for feed when young. Wild oat patches are particularly good green feed, but other grassy weeds, such as quack grass, are also of high quality, generally similar to tame grasses. Weedy cereal crops can also be cut when green, providing good livestock feed and reducing weed seed return in those areas.

Russian thistle may be used as hay, for a significant portion of a beef cattle ration. Apparently it is surprisingly palatable, and of good quality. High ash levels can be a problem, especially for dairy cattle, if the proportion of Russian thistle in the diet is high. Another weed that becomes surprisingly palatable in dried hay is stinging nettle. Both weeds are highly nutritious.

Lamb’s-quarters has a long history of use for fodder in Europe. It was used especially for poultry, sheep and pig feed. Some caution is required, however, as it can be toxic if eaten in large quantities over long periods of time.

Farmers report that sheep especially like Canada thistle, and that cattle may prefer dandelions over alfalfa in a pasture. Wild mustard can be palatable in young stages, before it sets seed. Seeds of mustard family weeds can be toxic, so grazing or harvesting early is best.

Kochia has a history of use as emergency feed in times of drought on the prairies. If harvested young, before it goes to seed, Kochia has similar nutrition to alfalfa. It has good energy and good protein, but in large amounts can have a laxative effect. Kochia can be as much as 50% of the weight of dry feed if harvested young, but only 30% if more mature plants are used.

Weeds can be high in nitrates. It is prudent to test weeds for feed quality before using them extensively. This is especially true during times of drought, following frost, or when more mature weeds are used. Ensiling reduces nitrate concentration, and makes weeds more acceptable as feed.

Other toxic compounds can be found in weeds. Redroot pigweed and lamb’s-quarters, for instance, contain oxalates, and thus should not be used as sole feed. Here, as in so many areas of farm management, a diverse mix is best to avoid problems. Experienced livestock managers may be able to judge the suitability of different weed mixtures by watching the response of the animals.

Chaff, including weed seeds, can also make up a significant portion of the ration of wintering beef cattle or sheep. Screenings can also be used. Weed seeds can be highly nutritious. Wild oat seeds are especially valuable. Lamb’s-quarters, redroot pigweed, Kochia, Russian thistle, and mustards have good protein levels. The amino acid composition of wild buckwheat is especially good.

Mustard family weeds are not especially palatable, and can be toxic. They should form a relatively small proportion of a feed mixture. Smaller weed seeds may survive their passage through livestock, and deliver a flush of weeds when manure is returned to the land. This can be avoided by grinding the seeds in a hammer mill, or by cooking or pelleting. Hammer mills also break awns of wild oats and foxtail barley, and make them more palatable.

Ground, pelleted screenings can be a significant portion of the diet for many animals. Some producers report that they have sold weedy screenings from organic crops, to be pelleted for livestock feed, at 15 cents or more per pound. On a per pound basis, this rate is similar to the average price for organic wheat, and is well ahead of the average price for wheat sold into the conventional market.

Perhaps in the future we will be more grateful for the plants nature provides, and find ourselves considering ways to increase our weeds, rather than ways to eliminate them. Some organic farmers in Saskatchewan are already musing over the possibility of insuring not only their grain crops, but also their “material other than grain”, including their weeds. In my next article, I will share some reasons to consider weeds as potential crops.


Brenda Frick, Ph.D., P.Ag., is the Prairie Coordinator for the Organic Agriculture Centre of Canada at the College of Agriculture, University of Saskatchewan. She welcomes yoxr comments at 306-966-4975 or via email at brenda.frick@usask.ca


This article first appeared in The Western Producer, and is published here on the OACC website with permission.


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Posted April 2005