In Jain Dharma, byasna is a period of intensified discipline and restraint. For many practitioners, this means avoiding indulgences and foods that tempt or distract the mind.

• Ice cream: Generally not recommended during byasna. It is a dessert item that many choose to avoid during solemn periods of austerity, especially for strict followers who minimize sweet or rich foods.
• Dairy products: Dalit to the tradition, dairy is not strictly forbidden, but during byasna many depend on the level of austerity one observes. If dairy is consumed, it should be pure and simple, and ideally not treated as an indulgence.
• Digambar vs. Śvetāmbar: There can be differences in practice. Śvetāmbar communities may have varying allowances for dairy, while Digambar communities tend to be more stringent in certain vows. The exact ruling can differ by local guru or sangh.

If you want a precise ruling, please share which tradition you follow (Digambar or Śvetāmbar) and your specific vow level, and I can summarize the common stance from authentic Jain sources used in that tradition.