Common Name
Puncture vine, goats head, caltrop.
Botanic Name
Tribulus terrestris
Plant Family
A common weed of dry sandy soils of waste areas, roadsides
Animals Affected
Cattle and sheep.
Toxic Principle
A number of saponins have been found in the plant. In addition, a fungal toxin in the plant may be associated with hepatogenic photosensitivity in livestock. The development of photosensitivity appears to be secondary to obstruction of the biliary system with a crystalloid substance that causes the formation of microliths(stones). The formation of microliths in the bile ducts causes the retention of phylloerythrin and the development of photosensitivity.
A prostrate, annual weed with recumbent stems which are pubescent and branching occasionally up to 3 feet in length. Leaves are opposite and pinnately compound with leaflets occurring in 4 to 7 pairs, oblong, elliptical, and about 1/2 inch long. Flowers are solitary, occurring in the axils of the leaves with a corolla composed of 5 yellow petals. The fruit is a small, hard, capsule which breaks apart into 5 spiny sections, each having 2 prominent, sharp, woody spines, that resemble a goat head. Puncture vine is similar in appearance to hairy caltrop (Kallstroemia hirsutissima), differing in the very hairy leaves and stems of the latter.
Lameness due to spiny burs.
Provide shade and protection from the sununtil photosensitization subsides. Mortality is often high.
Integumentary System
Photosensitization, Sheep may develop swelling of the head due to the photosensitization.
Hepatic System
Jaundice. Biliary stasis.
Photosensitivity secondary to cholecystitis.
Special Notes
Puncture vine is not a common problem to sheep unless other forages are scarce.
Tribulus terrestris showing spiny fruit.