Hanash ibn al-Harith reported that his father said, "One of ourmen had a mare which became pregnant which he then slaughtered, saying,'Will I live long enough to ride this horse?' Then we received 'Umar'sletter telling us to attend to the provision that Allah has given us inorder to make it thrive since there is still time in the business."
English reference: Book 27, Hadith 478
Arabic reference: Book 1, Hadith 478