Muwatta Imam Malik Book of Hajj, Hadith 145

ahya related to me from Malik from Hisham ibn Urwa that his father said, "If necessary, ride on your sacrificial animal, without burdening it, and if necessary, drink its milk after its young one has drunk its fill, and when you sacrifice it, sacrifice the young one with it."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، أَنَّ أَبَاهُ، قَالَ إِذَا اضْطُرِرْتَ إِلَى بَدَنَتِكَ فَارْكَبْهَا رُكُوبًا غَيْرَ فَادِحٍ وَإِذَا اضْطُرِرْتَ إِلَى لَبَنِهَا فَاشْرَبْ بَعْدَ مَا يَرْوَى فَصِيلُهَا فَإِذَا نَحَرْتَهَا فَانْحَرْ فَصِيلَهَا مَعَهَا .