Mature Kochia Contain a Liver Poison
Even though it is widely known there is a liver poison in mature Kochia weeds (Fireweed), considerable quantities of Kochia hay are harvested. Particularly this was true during the drought in the late summer and fall in western Kansas and eastern Colorado as an emergency feed for beef cattle.

Probably Enough Energy and Protein for a Dry Cow
Kochia weed hay, if harvested early enough, will probably support the maintenance of a beef cow. Mature Kochia hay might need to be supplemented with a little grain and protein.

However, there are some potential problems with this forage. The first problem is as the plant matures it contains an alkaloid. This is a liver poison that interferes with growth. The second problem is that it blocks the digestion of carotene and causes photosensitization. Kochia also accumulate oxalates and nitrates. Oxalates interfere with calcium absorption and nitrates can be toxic.

Polio encephalomalacia has also been reported with feeding or pasturing Kochia weeds. This "Polio" malady is thought to be complicated with sulfates in the water and feed. The treatment for Polio is thiamine (B1) injections. Work with your veterinarian to help prevent and treat these problems.

If Kochia is Fed, Keep Animals Away From Green Feed
In addition to the growth depression problem, when cattle eat green feed, such as wheat pasture, they become photosensitized. The alkaloid present in the Kochia causes the breakdown product of carotene (phylloerythin) in the wheat to not be excreted. This then builds up in the blood plasma and then in the skin. The skin, particularly white areas of animals, muzzles and udders become crusty.

My Field Experience
I have observed two cases of photosensitization of cattle. The first one was in eastern Colorado. Mature Kochia hay was harvested, ground through a tub grinder and added to growing rations at the feedlot. No problems were observed, until the cattle were turned out to wheat pasture. Some of the cattle became photosensitized, particularly the Holstein cattle.

The second experience was during the summer time. Several Holstein heifers were being pastured near the Arkansas river east of Dodge City that contained Kochia weeds. Some of the cattle broke out of the pasture and were found in a corn field. The corn was 8 to 10 feet high, and it was difficult to roundup the cattle. When the cattle were found they were photosensitized. The skin on the white areas was like cardboard. The cattle were very uncomfortable. The owner confined the cattle in a dark barn and they slowly recovered.

Bottom Line -- Poor Forage, a Poor Buy
There is usually a better solution than investing in the cost of harvesting, transportation, and feeding low quality or questionable forages. Grain and supplement along with some quality forage, with a limited intake system of feeding, appears to be a better solution during periods of drought. ©