Sowing and reaping are, however, mere episodes in the life of the _Llanero_. He is mainly occupied with cattle-breeding. The quality of the pasture differs considerably according to the nature of the soil and the good and bad character of the season. Sometimes it forms a thick carpet under the brushwood, but in other places it is poor and there is nothing but the leaves and pods of the _algarroba_. If the herd is too large, the grass will not grow again; the breeder recognizes at a glance the _campo recargado_--the field which has had its capacity overstrained. The pasture has to be carefully nursed. But the most urgent problem is to get a supply of water for the cattle. Round the Sierra the underground water is often fresh, and there are plenty of wells. Still, in order to avoid having to draw the water, they dig large trenches at suitable spots in the clay, and round these they arrange the earth that has been dug out, with an opening toward the hills to catch the water when it is raining. These are the _represas_. As in the case of the _banados_, ridges of earth direct the stream to the _represa_. It is surrounded by a hedge as carefully as the field is. On the plain rain is rare, and the _represas_ are usually the only reserve. They have to last the whole year; even two years if there is a particularly dry summer that prevents re-filling. Thus they become sometimes veritable lakes. From a distance you can see, above the top of the brushwood, the bald curve of the mound of beaten earth which encircles them. The water flows over it when there has been much rain. The mound is sometimes 4-1/2 to 5-1/2 yards high; as it is at Tello, between the Sierra d'Ulapes and the Sierra de los Llanos, where the San Juan coach used to change horses. The _represa_ is the real centre of the estate. The house is built near it, and guards the entrance. From early morning until dusk the cattle come to it, singly or in groups. The rancher admits them, lets them drink, and closes the gate behind them. If the thirsty cattle have not his mark and belong to a neighbour, he sends them to drink at their own _represa_; but he gives water to lost beasts, from a distance, whose owner will presently come for them. Near the _represa_ is the enclosure (_potrero_) for calves that have just been born. The cows come there every morning, and they are milked for a few months to make cheese. Like the _cerco_, the _represa_ is the personal property of the man who made it, or of one who has inherited it and sees to its upkeep.