In addition to the conditions mentioned previously, the zakat of camels, cows, and sheep has one more condition: the animal must graze in open fields for the entire year. Therefore, if it grazes on pre-cut grass during the entire year or part of the year, or it grazes on crops belonging to its owner or someone else, it is not liable for zakat.
However, if during the entire year the animal grazes on only a small amount of the owner’s grass such that it can be commonly said that the animal has grazed the entire year in open fields, zakat on it becomes obligatory.
Furthermore, with regard to camels, cows, and sheep, it is not a condition that they must not have worked during the entire year; rather, zakat on them is obligatory if they are used [a little] for irrigation, ploughing, and similar work, as long as it can be commonly said that they have not worked [significantly]. In fact, even if this cannot be said, based on obligatory precaution, zakat on them must be given.