Narrated Anas:

Abu Bakr , wrote to me about the Zakat which Allah had ordered His Apostle to observe: Whoever had to pay Jahda (Jahda means a four-year-old she-camel) as Zakat from his herd of camels and he had not got one, and he had Hiqqa (three-year-old she-camel), that Hiqqa should be accepted from him along with two sheep if they were available or twenty Dirhams (one Durham equals about 1/4 Saudi Riyal) and whoever had to pay Hiqqa as Zakat and he had no Hiqqa but had a Jadha, the Jadha should be accepted from him, and the Zakat collector should repay him twenty Dirhams or two sheep;
and whoever had to pay Hiqqa as Zakat and he had not got one, but had a Bint Labun (two-year-old she-camel), it should be accepted from him along with two sheep or twenty Dirhams;
and whoever had to pay Bint Labun and had a Hiqqa, that Hiqqa should be accepted from him and the Zakat collector should repay him twenty Dirhams or two sheep;
and whoever had to pay Bint Labun and he had not got one but had a Bint Makhad (one-year-old she camel), that Bint Makhad should be accepted from him along with twenty Dirhams or two sheep.

حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ، قَالَ حَدَّثَنِي أَبِي قَالَ، حَدَّثَنِي ثُمَامَةُ، أَنَّ أَنَسًا ـ رضى الله عنه ـ حَدَّثَهُ أَنَّ أَبَا بَكْرٍ ـ رضى الله عنه ـ كَتَبَ لَهُ فَرِيضَةَ الصَّدَقَةِ الَّتِي أَمَرَ اللَّهُ رَسُولَهُ ﷺ " مَنْ بَلَغَتْ عِنْدَهُ مِنَ الإِبِلِ صَدَقَةُ الْجَذَعَةِ، وَلَيْسَتْ عِنْدَهُ جَذَعَةٌ وَعِنْدَهُ حِقَّةٌ، فَإِنَّهَا تُقْبَلُ مِنْهُ الْحِقَّةُ وَيَجْعَلُ مَعَهَا شَاتَيْنِ إِنِ اسْتَيْسَرَتَا لَهُ أَوْ عِشْرِينَ دِرْهَمًا، وَمَنْ بَلَغَتْ عِنْدَهُ صَدَقَةُ الْحِقَّةِ وَلَيْسَتْ عِنْدَهُ الْحِقَّةُ وَعِنْدَهُ الْجَذَعَةُ، فَإِنَّهَا تُقْبَلُ مِنْهُ الْجَذَعَةُ، وَيُعْطِيهِ الْمُصَدِّقُ عِشْرِينَ دِرْهَمًا أَوْ شَاتَيْنِ، وَمَنْ بَلَغَتْ عِنْدَهُ صَدَقَةُ الْحِقَّةِ وَلَيْسَتْ عِنْدَهُ إِلاَّ بِنْتُ لَبُونٍ فَإِنَّهَا تُقْبَلُ مِنْهُ بِنْتُ لَبُونٍ، وَيُعْطِي شَاتَيْنِ أَوْ عِشْرِينَ دِرْهَمًا، وَمَنْ بَلَغَتْ صَدَقَتُهُ بِنْتَ لَبُونٍ وَعِنْدَهُ حِقَّةٌ فَإِنَّهَا تُقْبَلُ مِنْهُ الْحِقَّةُ وَيُعْطِيهِ الْمُصَدِّقُ عِشْرِينَ دِرْهَمًا أَوْ شَاتَيْنِ، وَمَنْ بَلَغَتْ صَدَقَتُهُ بِنْتَ لَبُونٍ وَلَيْسَتْ عِنْدَهُ وَعِنْدَهُ بِنْتُ مَخَاضٍ، فَإِنَّهَا تُقْبَلُ مِنْهُ بِنْتُ مَخَاضٍ وَيُعْطِي مَعَهَا عِشْرِينَ دِرْهَمًا أَوْ شَاتَيْنِ ".