By Mary Slosson

SACRAMENTO, California (Reuters) - A slaughterhouse in California's central agricultural heartland was allowed to reopen on Monday after agreeing to improve its handling of animals following a graphic video that showed cows being mistreated there, the U.S. Department of Agriculture said.

The USDA suspended operations at the Central Valley Meat Company earlier this month after animal rights activists gave it a video showing cows at the facility flailing wildly as they are dragged by one leg on a conveyor belt on their way to be slaughtered.

"The company has committed to a number of corrective actions including additional humane handling training for employees and safeguards to ensure that only ambulatory animals are processed," an agency spokesman said in an email.

The plant was allowed to resume operations as of Monday morning, although an investigation into possible food safety violations is continuing.

The company still is suspended from supplying meat to federal food programs, including the National School Lunch Program to which it contributed prior to the video's release, the USDA said.

The video, published online by activist group Compassion Over Killing, shows lame, sick former dairy cows being shot in the head multiple times and struggling before they die. In one portion of the video, a worker stands on a cow's nostrils to kill it after the cow is shot in the head.

An undercover activist shot the video at the farm in June and July, the animal rights group said.

Central Valley Meat Company said the closure of its facility caused economic hardship for the 450 people that work at the family-run plant.

"We have worked closely with both inspectors and industry experts while developing our USDA-approved action plan," the company said in an emailed statement. "As a result, Central Valley Meat will provide better training for our workers, better monitoring of our facilities, and more frequent third-party audits of our operations."

The company told Reuters at the time of its suspension that it had retained an outside animal welfare expert to conduct an internal investigation.

In 2008, the Humane Society of the United States captured employees of a California meatpacking plant in Chino torturing cattle and processing the unfit animals for human consumption in a gruesome undercover videotape.

That video's release led to the record recall of nearly 143 million pounds (65 million kg) of meat by the Hallmark/Westland Meat Packing Company.

(Reporting by Mary Slosson; Editing by Cynthia Johnston)