Livestock producers depend on the health of the land and of the animals they produce. Sustainable ranching requires effective yearly and seasonally-adapted management by ranchers. Beef cattle production is the top agricultural product in the state, ranked by market value at the gate. As of January 1, 2006, there were 940,000 cattle and calves in the state, with an average herd size of 200 head. Cattle ranching in Arizona is dependent on the use of public and private rangelands for grazing.