The U.S. Marine Corps says that 1,374 of the 40,000 troops assigned to Camp Pendleton's I Marine Expeditionary Force have or will undergo "live tissue training" involving the wounding of anesthetized pigs that are later destroyed.

The controversial training that is scheduled to last until November is coming under increasing scrutiny in Congress and elsewhere with calls to halt the practice.

Others, such as local Reps. Darrell Issa and Duncan Hunter, say it's a vital element of training for troops headed to war.

The training is taking place at a private avocado grove in Valley Center, where Deployment Medicine International conducts classes under a $1 million contract with the Marine Corps.

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The troops learn not only how to recognize and treat a wound, but also come away with a psychological preparedness for what they may encounter on the battlefield.

Animal rights groups are among those who contend that there are better ways to provide such training, citing realistic medical mannequins or embedding medics and others in civilian trauma centers.

Issa, R-Vista, whose district includes the property where the training takes place, supports the methodology.

"We have great responsibility to ensure that our deployed Marines have the most competent medical support possible," Issa said in a prepared statement. "I support the continued use of the most effective training methods for Marines and corpsmen. Our Marines will see their comrades' blood in real combat -- they need to be prepared for real-life trauma."

Hunter agreed.

"If it saves lives, it's important," said Hunter, R-El Cajon, who served two tours in Iraq and one in Afghanistan as a Marine officer before being elected to Congress last year.

"It's wartime and we have guys dying at an unprecedented rate in Afghanistan," he said. "It's not harming any people -- they're pigs."

But another area congressman, Rep. Bob Filner, D-San Diego and chairman of the House Armed Services Committee, signed a letter on July 9 asking the military to stop using pigs in medical training.

The letter, sponsored by Rep. Henry Johnson, D-Ga., was sent to Army officials and says that use of medical simulators and placing troops in hospital emergency rooms can readily replace the current practice that has been employed at various sites around the country since 2006.

The Army and other services' special forces units also take part in the training.

"Since your current use of animals for this training involves inflicting traumatic injuries upon animals, we endeavor to help the Army expedite all possible methods of animal replacement," the July 9 letter signed by 15 members of the House reads. "For these reasons, we would like to see a thorough evaluation of the current methods of combat trauma training."

At the national offices of the Humane Society in Gaithersburg, Md., just outside Washington, a spokesman said the military should stop using pigs.

"While the goal is right, the means are all wrong," said Martin Stephens, the society's vice president for animal research.

"These exercises are stuck in the 20th century, and we believe it is inhumane and insensitive," Stephens said. "What our soldiers need is repeated practice on realistic mannequins with the correct anatomy, and not a single exercise with an animal."

Stephens said there are "amazingly lifelike" mannequins that have fluids and simulated blood.

"The onus is on the military to clarify what the weakness of these mannequins might be, because we don't know of any," he said.

Repeated efforts to speak with a Deployment Medicine International official for more detail about its curriculum and how the pigs are specifically wounded have been unsuccessful.

The Marine Corps is attempting to find a troop who has undergone the training, used it on the battlefield and can speak about his experiences.

Animals rights activists and supporters such as Lea Voight of Vista say there is nothing that the military can say that will adequately defend the use of live pigs.

"I don't care if they're anesthetized or not," said Voight, who contacted this newspaper after it first profiled the Valley Center training last week.

"It's totally wrong," Voight said. "They are going to prepare themselves for gaping wounds by causing gaping wounds? It makes no sense."

Voight also said she believes the training should be conducted on mannequins.

The owner of the Valley Center avocado grove, Escondido police Officer Dave Bishop, has said he does not receive any money for hosting the training on his property.

Efforts to reach Bishop in recent days have been unsuccessful.

The training came to light after a noise complaint was filed against Bishop stemming from his use of recorded battlefield sounds.

San Diego County animal services officials last week witnessed the training with pigs and say it is conducted humanely.

"No laws were being broken," the county said in a written statement. "The pigs … are subject to guidelines approved and regulated by the United States Department of Agriculture Animal and Plant Health Inspection Service. The pigs were anesthetized without regaining consciousness during the training exercise and were euthanized at the end of the exercise."

Call staff writer Mark Walker at 760-740-3529.