All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhiwasallam, is His slave and messenger.
You are required to calculate the cash money in your possession by the end of every lunar year since you bought the cattle if you purchased them with money that is less than the Nisaab (i.e. the minimum amount liable for Zakah). Otherwise, the lunar year should be calculated in relation to the capital with which you have bought the cattle. Then, add the market value of your cattle; if the total amount reaches the Nisaab, the equivalent of 85 grams of gold or 595 grams of silver, you will be obliged to give 2.5% thereof. You are not obliged to payZakah on the cattles according to the ruling of Zakah on cattles since they are commercial commodities.
Allaah Knows best.