حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّهُ كَانَ يَقُولُ إِذَا نُحِرَتِ النَّاقَةُ فَذَكَاةُ مَا فِي بَطْنِهَا فِي ذَكَاتِهَا إِذَا كَانَ قَدْ تَمَّ خَلْقُهُ وَنَبَتَ شَعَرُهُ فَإِذَا خَرَجَ مِنْ بَطْنِ أُمِّهِ ذُبِحَ حَتَّى يَخْرُجَ الدَّمُ مِنْ جَوْفِهِ ‏.‏

Yahya related to me from Malik from Nafi that Abdullah ibn Umarsaid, "When a she-camel is slaughtered, what is in its womb isincluded in the slaughter if it is perfectly formed and its hair hasbegun to grow. If it comes out of its mother's womb, it is slaughteredso that blood flows from its heart." Translation Not Available

Book Ref: Muwatta Imam Malik Book 24 Hadith 1053
Web Ref:  Muwatta Imam Malik Book 24 Hadith 8