Is There Zakah on Livestock?
Question

What is the nisab of an`am animals for zakah?
Praise be to Allah.Zakah on livestock
The an`am animals are camels, cattle and sheep. No zakah is due on any other animals unless they are for trade. 
Zakah on camels
The nisab of camels is five, according to scholarly consensus, on which a sheep is to be given (as zakah). For ten camels, two sheep must be given; for fifteen, three sheep; for twenty, four sheep; for twenty-five, a bint makhad (a she-camel in its second year), and so on, as narrated in the hadith, as we shall see below. 
Based on this, whoever owns four camels or less does not have to pay zakah, unless he wants to. 
The basic principle concerning that is the hadith narrated by al-Bukhari (1454) from Anas, according to which Abu Bakr (may Allah be pleased with him) wrote this letter to him when he sent him to Bahrain:
In the name of Allah, the most Gracious, the Most Merciful. This is the obligation of zakah which the Messenger of Allah (peace and blessings of Allah be upon him) enjoined upon the Muslims and which Allah enjoined upon His Messenger. Whoever among the Muslims is asked for it in the proper manner, let him give it, and whoever is asked for more than that, let him not give. For twenty-four camels or less, for each five, one sheep. If the number reaches twenty-five up to thirty-five, then a female bint makhad (a she-camel in its second year) is due. If the number reaches thirty-six up to forty-five, then a female bint labun (a she-camel in its third year) is due. If the number reaches forty-six up to sixty, then a hiqqah (a she-camel in its fourth year) is due. If the number reaches sixty-one up to seventy-five, then a jadha’ah (a she-camel in its fifth year) is due. If the number reaches seventy-six up to ninety then two bint labun are due (she-camels in their third year). If the number reaches ninety-one up to one hundred and twenty, then two hiqqah are due (she-camels in their fourth year…). If there are more than one hundred and twenty, then for every forty a bint labun is due and for every fifty a hiqqah. Whoever has no more than four camels does not have to pay zakah on them unless their owner wants to give. If the number reaches five camels, then one sheep is due…” 

A bint makhad is a camel that has completed one year.
A bint labun is one that has completed two years.
A hiqqah is one that has completed three years.
A jadha’ah is one that has completed four years.  

Zakah on cattle
The nisab for cattle is thirty, according to the majority of scholars, because the Prophet (peace and blessings of Allah be upon him) said: “For thirty cattle a tabi’ or tabi’ah is due, and for every forty a musinnah.” Narrated by al-Tirmidhi, 622; Ibn Majah, 1804; classed as sahih by al-Albani in Sahih al-Tirmidhi. 

The tabi’ (male) or tabi’ah (female) is a bovine that is one year old and has entered its second year. It is so called because it follows (yatba’) its mother. 
The musinnah is that which is two years old. 

Zakah on sheep
The nisab for sheep is forty, according to scholarly consensus, for which one sheep is due, because of the hadith narrated by Anas which is quoted above: “The zakah for sheep in the pasture: if the number is forty up to one hundred and twenty, one sheep is due. If there are more than one hundred and twenty, up to two hundred, then two sheep are due. If there are more than two hundred, up to three hundred, then three sheep are due. If there are more than three hundred, then for every hundred, one sheep is due. And if the flock of a man is less than forty sheep, then no zakah is due unless their owner wants to give.” 
The majority of jurists stipulated that in order for zakah on an'am animals to be obligatory, they must be in the pasture, i.e., they graze in the pasture for most of the year . As for those which are given feed, no zakah is due on them unless they are for trade. The evidence that their being pastured is a condition of zakah is to be found in the words of the Prophet (peace and blessings of Allah be upon him): “The zakah on sheep in the pasture…” (See al-Mughni, 2/230-243)
It says in Fatawa al-Lajnah al-Daimah (9/202): 
“The scholars are unanimously agreed that zakah is obligatory in the case of grazing camels, cattle and sheep , if their number reaches the nisab. The minimum number in the case of camels is five, in the case of cattle it is thirty and in the case of sheep it is forty. Grazing animals are those that eat grass etc in the pasture, unlike those that are given feed and working animals that are used for carrying loads. 
The scholars differed as to whether zakah is due on animals that are given feed and working animals. The majority of scholars are of the view that no zakah is due on them because of the report narrated by Ahmad, al-Nasai and Abu Dawud from Bahz ibn Hakim, from his father, from his grandfather, who said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: “For grazing camels, for every forty a bint labun…” So the obligation to pay zakah is limited to camels that are grazing, and it is not required in the case of those that are given feed. As for working camels, there is the hadith of ‘Ali (may Allah be pleased with him): “There is no zakah on working animals.” Malik and a number of other scholars were of the view that zakah is obligatory on animals that are given feed and working animals too.”
For more, please see the answers to question no. 99061 and 105320 .
And Allah knows best.