Sheep follow a similar reproductive strategy to other herd animals. Wealth is counted by how large the herd of cattle is. Heracles then had to herd the cattle back to Eurystheus. Konguro'o also hung on the neck of the leader goat, which the sheep herd followed. It is the only continuously wild bison herd in the United States. Intensive systems focus towards maximum production per cow in the herd. High priority is given to maintaining the genetic purity of the native red deer herd. Hunting is also allowed every year in the Henry Mountains bison herd in Utah. One wolf travelled to a herd away. It was the first breed to record pedigrees in herd books. Sitaralak imitates the power of a herd of stampeding elephants. A Comanche man's wealth was measured by the size of his horse herd. The islands are notable for having Ontario's largest herd of boreal woodland caribou. The size of the average dairy herd in the Waikato has progressively increased. The herd total in 2009 was 5,090 animals.