That's the wrong answer. This is Yew. Yew trees are extremely toxic to horses and all grazing animals. Yew poisoning is the commonest form of animal poisoning.
Yew contains an alkyloid that depresses the action of the heart.
Yew needles are greenish-yellow on the under surface and have no white stripes. A veterinarian should be consulted immediately for supportive treatment to reduce the damage caused by ingestion of poisonous plants. This information is provided as a public service, but we cannot guarantee that the information is current or accurate. Readers should verify the information before acting on it.