Mistletoe, kiss of death?

Oak with mistletoe
Photo credit: Lynn Ketchum
Q:

Jackson County Health Department has asked for information on the degree (if any) of toxicity to livestock, cattle and horses specifically.

- Jackson County, Oregon
A:

Pregnant cows consuming mistletoe have been reported to abort their calves. Try to move cattle away from the mistletoe or other toxic plants by feeding some baled hay in an area away from the site. Also consider using electrified temporary fencing to keep animals out of the area.


Some cattle have died from eating mistletoe (LORANTHACEAE Western Mistletoe). Mistletoe is a conspicuous parasite on oak (rarely on alder). The entire plant is velvety-hairy; stems stout, bushy-branched, 1 to 2 feet long, forming dense clumps; leaves thick and leathery, broad, up to 1 inch long, short-stalked; flowers inconspicuous in short spikes in the leaf angles; berries pearly-white to slightly pinkish, occurring only on female plants. Western mistletoe is regarded by some authors as variety villosum of the eastern species, Phoradendron flavescens (Pursh) Nutt. Ordinarily, it appears to be unpalatable to them, but occasionally they develop an abnormal taste for it. Symptoms of poisoning In the cases on record, animals poisoned by mistletoe died suddenly with no apparent evidence of suffering. Several species of closely related mistletoe occur in southern Oregon and California, Arizona, New Mexico, and northern Mexico. One which extends northward to east-central Oregon is variety ligatum of Phoradendron juniperinum Engelm. In central Oregon it is parasitic on Juniper, and it can be recognized by the leaves which are reduced to scales and by the usually deep pink or red berries. Read more about poisonous plants found in Oregon.

Shelby Filley
Regional Livestock and Forage Specialist
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