Ata' ibn AbuRabah asked Aisha: Can women offer prayer on a riding beast? She replied: They were not permitted to do so in hardship or comfort. Muhammad ibn Shu'ayb said: This (prohibition) applies to the obligatory prayers.  

أَنَّهُ سَأَلَ عَائِشَةَ ؓ هَلْ رُخِّصَ لِلنِّسَاءِ أَنْ يُصَلِّينَ عَلَى الدَّوَابِّ قَالَتْ لَمْ يُرَخَّصْ لَهُنَّ فِي ذَلِكَ فِي شِدَّةٍ وَلاَ رَخَاءٍ قَالَ مُحَمَّدٌ هَذَا فِي الْمَكْتُوبَةِ