Manava Dharmashastra 4.67

4.67

avinītā adāntā gāvo'śvāśvatarādayaḥ | dhuryā dhuraṃ vahanti yujyante | gantrādyederupalakṣaṇam | cagrahṇam, aniyuktairapi dhuri, kevalairadāntaiḥ gamanaṃ neṣyate | bhagnaṃ śṛṅgaṃ yasya anaḍuhaḥ, tasyaiva śṛṅgasambhavaḥ, nāśvādeḥ | vāladhiḥ pucchastena virūpitāḥ chinnapucchādyayaḥ | tādṛśena na yāyāt | ārohaṇameva smṛtyantare pratiṣiddham |

Medhātithi’s commentary (manubhāṣya):
‘Untrained’—i.e., not trained; oxen, horses, mules and so forth, which are yoked to chariots, etc. The use of ‘ca’ indicates that one shall not ride upon untrained beasts,???en (even?) when they are not yoked to chariots, etc.

The ‘injured horn’ pertains to the ox only; as that alone has horns, and not horses and other animals.

‘Bāladhi’ is tail; those that have been disfigured by their tails; whose tails have been cut off.

One should not travel on such animals. Another Smṛti text prohibits merely getting upon the back of such animals.—(67)