מדרש אויף דברים 14:28

"and the Levite in your gates, for he has no portion or inheritance with you": Wherever you find the Levite, give him his portion (first-tithe). If he has no portion, he gives him poor-tithe. If he has no poor-tithe, he gives him peace-offerings.

Whence do I derive the same for the beast tithe? From "tithe shall you tithe."

(Devarim 14:28) "(If one delayed giving his tithes of the first and second years) From the end of three years, you shall remove all the tithe of your produce": I might think, even on the festival; it is, therefore, written (Ibid. 26:12) "When you finish tithing" (and the tithing of the third year's produce is not completed until Channukah of the fourth year).