Soviet Union flight testing used animal test subjects, mainly dogs, sometimes rabbits, during the 1950s.  
The stamp above shows Laika posing inside her space box before her orbital mission on November 3, 1957
with the R-7 ICBM shown lifting off and configured for Sputnik-2.  To the lower right we see a happy space
dog peering out the hatch of a R-2A upper stage which has just made a parachute landing after a high
altitude vertical flight.  These up and down flights began in the early 1950s and lasted until the late 50s
after Laika's orbital trip. The above souvenir sheet is from the Congo Republic.  Also see the vertical flight
stamp below,