Zakah on what exceeds the threshold: Abu Hanifah said it is due in proportion to the excess

Asim bin Kulayb narrates from his father: We used to be on jihad, and our commander was always one of the Companions. We were in Persia, and our commander was a Companion of the Messenger (peace and blessings be upon him) from the tribe of Muzaynah. Two-year-old calves became expensive for us (for the sacrifice), until we would buy one musinn (a two-year-old) for two or three jadha'ahs (a one-year-old cow). This (Companion of the Messenger (peace and blessings be upon him)) stood up and said: We too had such a day, when two-year-olds came to us at a high price, until we (too) would buy a musinn by giving two or three jadha'ahs. Then the Prophet (peace and blessings be upon him) stood among us and said: "A musinn animal suffices wherever a thani suffices."

A man from the tribe of Muzaynah (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) offered a sacrifice while on a journey.

It is reported from al-Hasan that he saw no harm in a man, when setting out on a journey, instructing his family to offer the sacrifice on his behalf. It is mentioned that the view of (Imam) Abu Hanifah is: Sacrifice is not obligatory on a traveller.