The Pentagon will scale back its use of live animals in medical training starting Jan. 1, the Defense Department's top doctor has said.

Instead, military health professionals will use simulators or other models in key areas of training and education such as advance trauma life support, neonatal resuscitation, obstetrics and gynecology and more.

The decision comes after the advocacy group People for the Ethical Treatment of Animals has lobbied DoD for years to halt all training that results in harm or death to goats, pigs, monkeys, rabbits, chickens and other animals the department uses in training.

Assistant Secretary of Defense for Health Affairs Dr. Jonathan Woodson said Friday that advanced technology and training have enabled the services to use fewer live animals in training.

"In some cases, [live animals] may offer the best training. However, new technologies and training techniques afford us opportunities to reduce our dependence on live animals while still maintaining an effective medical training program. We must achieve balance," Woodson said.

The Pentagon has had a policy in place since 2011 to use live animals only when alternatives like mannequins, actors, advanced simulators or cadavers could not provide the necessary training for proficiency.

But Justin Goodman, PETA's director of laboratory investigations, said that policy was not enforced, and a memo, issued May 15 by Woodson, offered the same conclusion.

"Our analysis found numerous variations within and among service programs. The data and these variations indicate that suitable simulation alternatives can replace the use of live animals in some cases," Woodson wrote.

The Army stopped using vervet monkeys in 2011 in nerve agent demonstrations and the Coast Guard earlier this year reduced the use of live animals in its medical training.

But the new instruction goes farther than any previous regulations, ordering all services to "fully transition to the use of simulations in these programs by no later than Jan. 1, 2015."

"The military health system uses animals to meet education and training standards to prepare medical personnel to care for those in harm's way. However, we must make progress towards the standardization, refinement, replacement and reduction of our use of the live-animal model," Woodson wrote.

The change does not appear to affect other training where live animals are used, including combat trauma training courses and survival training.

The protection of those animals remains a top priority for PETA, Goodman said.

"The primary concern of ours has been the use of animals in combat trauma training in which they are shot, stabbed and blown up, and while this new memo addresses some of it, it doesn't seem it will affect much of that kind of animal use," Goodman said.

PETA sent a letter in August to Defense Secretary Chuck Hagel urging DoD to "adhere to its own regulations" regarding simulator use over live animals and cited three recent studies that showed human simulators can work as well or better for teaching trauma skills.

Hagel responded in October, noting that DoD continues to work with fellow NATO members that don't use live animals in training to learn their best practices.

DoD also "continues to work with national and other international government organizations, industry and academia to conduct research, development testing and validation of new technologies for combat casualty care training," Hagel said.

In a report to Congress in 2013, Pentagon officials defended the use of live animals in training, saying the practice contributed to the high rates of survival of wounded troops in Iraq and Afghanistan.

In August, retired Army Col. (Dr.) Donald Jenkins asked the Defense Health Board to consider recommending that live-tissue training remain in the DoD medical curriculum.

Speaking on recent lessons learned from the battlefield, Jenkins and the board's trauma and injury subcommittee said DoD should continue funding research to compare cost and efficacy of live-tissue training programs compared with simulation, but added that animal training does have value.

"Live-tissue training has an important tailored role in trauma training for lifesaving interventions on the battlefield. ... It should be combined with high-fidelity simulation and integrated operational medical training across the force," Jenkins said.

Goodman said recent research indicates this is not true. "The studies confirm what we've been saying for years, which is that medical simulators that mimic human anatomy and physiology teach lifesaving battle skills as well as or better," he said.

According to the Physicians Committee for Responsible Medicine, the U.S. military uses about 8,500 animals every year in its training courses.

The number should drop after the new policy goes into effect, PETA officials said.

"This is the first time the military has ever instituted a policy that prohibits the use of animals for medical training in favor of simulation. It's a really landmark event that shows an about-face for an agency that historically has defended the use of animals. We're incredibly pleased and encouraged by it," Goodman said.