Yew (Japanese)
Latin Name: Taxus cuspidata
Other yews including Canada Yew (T. canadensis), English Yew (T. baccata), and Western Yew (T. brevifolia) are similarly toxic.
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
- Monogastrics - 0.1% of an animal’s body weight
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
- Monogastrics - 0.1% of an animal’s body weight