If what you mean by sacrifice, is the sacrifice performed as one of the rituals of Hajj where animals are sacrificed in the land of Mina, then according to the fatwa of the majority of jurists, if the animal originally had a horn in its creation (even if it might lack one now or it is broken), it will suffice for the sacrifice.[1]

Unless, the inside of the horn is broken or has been cut; in this case it will not suffice, but breakage of the outward horn will not cause a problem.[2]

If the sacrifice is not during Hajj and is with the intention of the pleasure of Allah, then the breakage of the horn will definitely not cause any problem for the validity of the sacrifice.

In any case, we asked the offices of the maraji’ your question, and this is the response we got:

Khameni, Sistani, Makarem Shirazi (may Allah prolong their lives): It is not problematic.

Saafi Golpaygani: Yes, Allah will accept the sacrifice Inshallah.