Cows of this kind are only for feeding and sometimes for producing milk. Some male cows are frequently used for farming. In this time, it is very hot and dry so they are sometimes left roaming in already harvested farms to eat the leftover hay.
According to Wikipedia, "Serrekunda (or Serekunda) is the largest city in The Gambia, lying southwest of Banjul. Its population as of 2006, was 335,733 people. Although Banjul is The Gambia's capital, it is on an island and cannot grow further, making much of the growth in Serrekunda."