May 12 (Reuters) - Hundreds of veterinarians, support staff, and lab workers at the animal health arm of the USDA have left under the Trump administration’s push for resignations, according to three sources familiar with the situation, leaving fewer specialists to respond to animal disease outbreaks.

The departures come as the country battles its longest-ever outbreak of bird flu and faces the encroachment of New World screwworm, a flesh-eating pest detected among cattle in Mexico.

“With the decrease in USDA veterinary positions, there is concern that fewer veterinarians will be able to perform ongoing regulatory requirements, disease investigations, and response planning and preparation,” Kansas animal health commissioner Justin Smith said.

“This could result in slower response times and less responsiveness to local veterinary needs,” he added.

Egg prices set records this year after bird flu wiped out millions of laying hens. Cases have slowed in recent weeks, though experts warn outbreaks could flare up again during the spring and fall migratory seasons for wild birds that spread the virus.

More than 15,000 USDA employees have taken President Donald Trump’s financial incentive to quit, about 15% of agency staff, as part of administration efforts spearheaded by billionaire Elon Musk to shrink the federal workforce.

In that exodus, the Animal and Plant Health Inspection Service, the agency that fights livestock diseases and pests that hurt crops, lost 1,377 staff. That represents about 16% of APHIS employees, according to a Reuters analysis of data from the federal Office of Personnel Management.

About 400 of those leaving worked in the agency’s Veterinary Services arm, representing more than 20% of its 1,850 staff, one source said. That branch works across the U.S. and globally with farmers to test animals for disease and control its spread.

The tally includes 13 of the agency’s 23 area veterinarians who oversee veterinary work across the country, according to a chart of staff departures seen by Reuters and a source familiar with the situation.

Also leaving are 20%-30% of staff at one USDA lab that tests for animal disease like bird flu, a second source said.

Those remaining must have all purchases above $10,000 approved by Musk’s Department of Government Efficiency, potentially adding up to four weeks of delay, the source said.

The USDA did not respond to a request for comment.