(a) Al-Zuhri says: I heard Sa'id bin al-Musayyib (may Allah have mercy on him) say: 'Al-bahirah' (bahirah) was the she-camel whose milk was forbidden; it was dedicated to the idols, so no one would milk it. And 'al-sa'ibah' (sa'ibah) is what they would let loose for their idols, and no one would load anything on it.
Sayyiduna Abu Hurayrah (may Allah be pleased with him) says: I heard the Messenger of Allah (peace and blessings be upon him) say: "I saw Amr al-Khuza'i dragging his intestines in Hell; he was the first person to start the custom of the sa'ibah."
(b) Ibn al-Musayyib (may Allah have mercy on him) says: 'Al-wasilah' (wasilah) is the young she-camel that bears a female at her first birth and then bears a female again the second time; they would also let it loose in the name of the idols, but only when it bore females twice in succession with no male between them.
(c) Ibn al-Musayyib (may Allah have mercy on him) says: 'Al-ham' (ham) is the stallion camel that mounts the females a number of times; they would also dedicate it to the idols and would not load anything on it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوقف / 11914