Sheep

Sheep were quadruped mammals found on Earth and domesticated by humans. They were raised mainly for food and wool.

In 3300 BC, a wounded sheep entered the TARDIS, where it gave birth to its lamb. The Second Doctor left to find the sheep's owner, but when he returned he found the sheep and lamb brutally slaughtered. (DWY: Loop the Loup)

In 2050, K9 briefly saw a sheep in the dream he shared with Alistair Gryffen. (K9TV: Dream-Eaters)

Sheep went extinct around 2106 after the Ozone Purge, though records of their existence survived. (NA: Lucifer Rising)

On earth, the Doctor went in sheep dip and tried to get sense out of a sheep. (NSA: The Glamour Chase)

The colonists to Metebelis III brought sheep with them. They survived the crash. They later became a food source for the colonists and Eight Legs, though the Eight Legs preferred human meat. (DW: Planet of the Spiders)

In the far future on Kirith, the Panjistri kept sheep on Kandasi Island as their main source of food. (NA: Timewyrm: Apocalypse)

Behind the scenes

 * In the dream world in K9TV: Dream-Eaters, K9 encounters a sheep, which his scanner verified as being 'electric'. This is a nod towards the Phillip K. Dick novel Do Androids Dream of Electric Sheep?.