Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrates that the Noble Prophet (peace and blessings be upon him) said: On thirty cows, one tabi' or tabi'ah (a one-year-old male or female calf) is obligatory as zakat, and on forty cows, one musinnah (a two-year-old male or female calf) is obligatory as zakat.