Narrated Ibn Juraij:
‘Ata’ said, “I heard Jabir bin ‘Abdullah (radiallaahu `anhu) saying, ‘We never ate the meat of the Budn for more than three days of Mina. Later, the Prophet (sallallaahu `alayhi wasallam) gave us permission by saying: ‘Eat and take (meat) with you. So we ate (some) and took (some) with us.’ ” I asked ‘Ata’, “Did Jabir (radiallaahu `anhu) say (that they went on eating the meat) till they reached Medina?” ‘Ata’ replied, “No.”
I heard ‘Aisha (radiallaahu `anhaa) saying, “We set out (from Medina) along with Allah’s Apostle (sallallaahu `alayhi wasallam) five days before the end of Dhul-Qa’da with the intention of performing Hajj only. When we approached Mecca, Allah’s Apostle (sallallaahu `alayhi wasallam) ordered those who had no Hadi along with them to finish the lhram after performing Tawaf of the Ka’ba, (Safa and Marwa). ‘Aisha (radiallaahu `anhaa) added, “Beef was brought to us on the Day of Nahr and I said, ‘What is this?’ Somebody said, ‘The Prophet (sallallaahu `alayhi wasallam) has slaughtered (cows) on behalf of his wives.’ “
This Hadith has been discussed before as well. Read it here.
Both these Ahadith give evidence that it’s okay to eat from the animal you sacrifice. Rather, it’s Sunnah. Prophet (sallallaahu `alayhi wasallam) encouraged companions to do so (as in the first Hadith), and sent some for his wives (as in the second Hadith). So eat from the meat whenever an animal is sacrificed (Eid/aqeeqah/Hajj etc.).