Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 7

Sanskrit:

वन्यैश्चरुपुरोडाशैर्निर्वपेत् कालचोदितान् ।न तु श्रौतेन पशुना मां यजेत वनाश्रमी ॥ ७ ॥

ITRANS:

vanyaiś caru-puroḍāśairnirvapet kāla-coditānna tu śrautena paśunāmāṁ yajeta vanāśramī

Translation:

One who has accepted the vānaprastha order of life should perform seasonal sacrifices by offering oblations of caru and sacrificial cakes prepared from rice and other grains found in the forest. The vānaprastha, however, may never offer animal sacrifices to Me, even those sacrifices mentioned in the Vedas.

Purport:

One who has taken the vānaprastha order of life should never perform animal sacrifices or eat meat.