Yew (Japanese)

Identifying Characteristics:

• Mostly planted as ornamental shrubs or bushes
• Woody
• 1/2 to 1" long evergreen leaves
• Lighter green on underside of needle
• Aril (looks like a berry) is red and blueberry-sized with a hole in the end

Plant Longevity:

• Perennial

Where Commonly Found:

• Old shrubs growing in pastures can be a concern, but the biggest concern is people placing clippings into pastures from landscape bushes

Time of Most Concern:

• When clippings are placed in pastures, when livestock get out of pasture and find yews in landscapes, or when the older leaves are consumed
• All seasons of the year

Compound that Causes Concern:

• Perhaps an alkaloid, taxine
  • Separrated into two fractions, taxine A and taxine B. – Taxine B is present in the greatest amount
• Alkaloid does not act as a cardiac glycoside but depresses conduction of depolarization through the heart
• Taxine and other diterpenoid alkaloids contain a slow-to-act gastrointestinal irritating oil

Part of Plant Most Toxic:

• Older leaves
• Seed if chewed

Livestock Species Affected:

• All livestock

Pasture, Stored Feed, Both:

• Both

Clinical Signs:

• Weakness
• Difficulty breathing
• Trembling
• Muscular weakness
• Vomiting
• Diarrhea
• Failure to produce milk
• Found dead

Amount Needed to be Consumed for Clinical Signs / Death:

• Green foliage is readily consumed and fatal at:
  • Monogastrics - 0.1% of an animal’s body weight
    • 1 lb plant material in a 1,000 lb horse
  • Ruminants - 0.5% of the animal’s body weight
    • 5 lbs plant material in a 1,000 lb cow