Why did texas have a surplus of cattle

It gained a surplus from the cattle that is left in the territory after the Mexican war.

Explanation:

The Need for cattle in the west was less as compared to the east because in the east the flourishing population created a huge demand for meat and beef.After the end of the civil war, thousands of wild longhorn cattle roamed in the great plains of Texas.soon local cowboys rounding up the wild cattle and trailing them to the north to the railroads of Kansas.From Kansas to wild longhorn cattle were shipped by the train to the slaughterhouses of the Chicago where they processed them.The economy of the east went into boom and the demand for meat and beef grew after the war.A new industry born.