California water authorities are ordering a Merced County dairy to clean up its property after more than 50 decomposing cow carcasses were found partially buried in manure.

Officials inspecting Rego Dairy say they also found evidence of manure runoff that was leaching into a drainage ditch, as well as dozens of dirty syringes in the ditch.

They say the dairy also had more than the 350 cows it was allowed to have under its permit.

The owner of the dairy didn't return telephone calls seeking comment.

State guidelines say dead livestock must be taken to rendering plants, while water quality rules require that manure lagoons be designed to prevent runoff.

Officials say wastewater at the dairy didn't go through a retention system, a requirement meant to prevent groundwater contamination.