In Jainism, the consumption of milk has traditionally been allowed, especially for householders (śrāvakas). Jain scriptures (śāstras) such as the Tattvārtha Sūtra and various commentaries do not explicitly prohibit milk. The reasoning is that, when cows are treated with compassion and not harmed, taking surplus milk does not involve violence (hiṃsā) on the scale of meat, eggs, or honey.

However, Jain ethics place supreme emphasis on ahiṃsā (non-violence). In ancient times, cows were kept with care and the practice did not generally involve himsā. In modern times, however, many Jain acharyas and followers point out that the dairy industry often involves significant cruelty to animals, which goes against the principle of ahiṃsā. As a result, some Jains, especially among the ascetic community and increasingly among lay followers, choose to avoid milk and dairy products altogether.

Summary:

• Traditional Jain shāstra allows milk, provided no violence is involved.
• Modern Jain thought increasingly discourages milk if its production involves hiṃsā.
• The highest ideal is to avoid all forms of violence, so some Jains now practice veganism.

References:

• Tattvārtha Sūtra, 7.11 (on five kinds of udumbara fruits, not including milk as prohibited)
• Pravachansār, Kundakunda (does not list milk as a forbidden item)
• Modern acharyas’ discourses on ahiṃsā and contemporary dairy practices

Conclusion: Milk is allowed as per traditional Jain shāstra, but if its production involves violence, it should be avoided in the spirit of ahiṃsā.