Weeds can be valuable as livestock feed – Organic Matters

At the recent Going Organic conference in Calgary, Brewster Kneen suggested that we live in a society that is “profoundly ungrateful.” I feel 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, especially livestock producers.

Most weeds are palatable and of acceptable quality for animal feed if they are grazed or cut 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 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, but high ash levels can be a problem if too much is used, especially for dairy cattle. Stinging nettle is also surprisingly palatable in dried hay. 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, because it can be toxic if eaten in large quantities over long periods of time.

Farmers report that sheep especially like Canada thistle and cattle may prefer dandelions over alfalfa in a pasture. Wild mustard can be palatable before it sets seed. Seeds of mustard family weeds can be toxic, so it’s best to graze or harvest early.

Kochia has long been used 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 act as a laxative. Kochia can be as much as 50 percent of the weight of dry feed if harvested young, but only 30 percent if more mature plants are used.

Weeds can be high in nitrates so it is prudent to test them for feed quality before using 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 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 make up a significant portion of the ration for 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 mustard 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, making them more palatable.

Ground, pelleted screenings can be a significant portion of the diet for many animals. 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.

Frick is the prairie co-ordinator for the Organic Agriculture Centre of Canada located at the University of Saskatchewan. Frick can be reached at 306-966-4975, at brenda.frick@usask.ca, or www.organicagcentre.ca.The opinions expressed in this column are not necessarily those of The Western Producer.

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