al-Zuhri ابن شهاب الزهري‎, محمد بن مسلم · Sacrifice (Kitab Al-Dahaya)

A man called the Messenger of Allah (ﷺ): We used to sacrifice Atirah in pre-Islamic days during Rajab; so what do you command us? He said: Sacrifice for the sake of Allah in any month whatever; obey Allah, Most High, and feed(the people). He said: We used to sacrifice a Fara' in pre-Islamic days, so what do you command us? He said: On every pasturing animal there is a Fara' which is fed by your cattle till it becomes strong…

Prophet (ﷺ) sa saying: There is no fara' and 'atirah.

When a boy was born to one of us in the pre-Islamic period, we sacrificed a sheep and smeared his head with its blood; but when Allah brought Islam, we sacrificed a sheep, shaved his head and smeared his head with saffron.