Arabic baghl, pl. bighal.
Muhammad forbade the breeding of mules, for Ibn ‘Abbas says the three special injunctions which he received were (1) to perform the ablutions thoroughly, (2) not to take alms, (3) not to breed mules. (Mishkat, book xvii. ch. ii.)
The flesh of a mule is unlawful. (Hidiyah, vol. iv. p. 74.)
They are not liable to zakat. (Hidayah, vol. i. p. 16.)
Based on Hughes, Dictionary of Islam