It depends on what characteristic you want to measure! Its mass, its height, the amount of body fat, the fineness of its fleece?
jolts or something
inches
Kilograms.
mililiters
a millimeter
You would typically use kilograms or pounds to measure the mass of a sheep.
Feet.
a centimeter
A shoe.
You would use CM or INCHES to measure a knife
Ounces or milliliters.
A kilometre.
meters
Square footage.
Kilograms.
tons
Centimeters