Salaam. My grandpa established a madrasa in my village. Every year, the madrasa arranges a prize-giving ceremony in honor of the students' results, and they have a program for it. Many Islamic speakers also come and give speeches. The madrasa also arranges a feast in this occasion, and they buy and sacrifice a cow to arrange dinner for the guests. Is this allowed, or is it included in innovations?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

We do not see anything wrong in what you mentioned, and it is not considered a religious innovation. Rather, it is hoped that the organizers would earn rewards for this good deed that involves teaching people through lectures and offering them food. Also, there is no harm in celebrating success and accomplishments, Allah willing, provided that it is free of the intention to boast and does not involve extravagance and wasteful practices. Proof of permissibility in this regard is the report of Ibn ʻUmar cited by Al-Khateeb on the authority of Maalik and by Al-Bayhaqi in his book Shuʻab Al-'Eemaan. It reads, "It took ʻUmar (ibn Al-Khattaab) twelve years to learn Soorah Al-Baqarah, and when he finished it, he slaughtered a camel (to feed the people of it)." [Ad-Durr Al-Manthoor]

When Ibn Hajar finished the final draft of his book Fat-h Al-Baari, he threw a huge banquet which none of the Muslims dignitaries at the time missed, except a few.

Siddeeq Hasan Khaan wrote, "When I learned about this incident, I threw a banquet to celebrate finishing my Tafseer (exegesis) book Fat-h Al-Bayaan." [At-Taaj Al-Mukallal]

Allah knows best.