EAST RUTHERFORD — A 2-year-old filly died mid-race at the Meadowlands Racing track on Friday.

Fox Valley Adele was leading the pack in race 6 of the New Jersey Sire Stakes 2-year-old Fillies Pace Final, which is a harness racing event. The young horse was overtaken about halfway through and almost immediately collapsed. Marcus Miller, Fox Valley Adele's driver, was not seriously injured.

Meadowlands Racing said in a statement on social media that the horse died of a "possible heart attack or aneurysm."

The race started around 8:20 p.m., according to a video of the event.

New Jersey 101.5 Chief Meteorologist Dan Zarrow, citing a nearby weather station located at the Meadowlands Environment Center in Lyndhurst, said that the temperature at the time had dropped to 81 degrees with a heat index of 84. Temperatures earlier in the day had reached a high of 95.

PETA on Friday sent a letter asking Monmouth Park in Oceanport to suspend its races due to the heat, New Jersey 101.5 reported.

"Horses are pushed to the limit every time they race, and the additional stress of skyrocketing temperatures can cause brain damage, collapse as a result of heatstroke, and fatal cardiac trauma," PETA wrote.

Monmouth Park canceled one race on Sunday shortly before 3 p.m. due to temperatures in the high 90s and did not resume racing until 4 p.m., BloodHorse reported. There were no reported horse deaths at Monmouth Park over the weekend.

Animal Wellness Action Executive Director Marty Irby said in a statement that Fox Valley Adele's death was a reminder of the importance of national oversight under the Horseracing Integrity and Safety Act, which took effect July 1.

"As the body count continues to climb, these rampant deaths continue to turn the betting public away from the horse racing industry, and if these deaths don’t stop, harness racing in America will soon go the way of the dinosaur.”

Includes prior reporting from Dan Alexander.

Rick Rickman is a reporter for New Jersey 101.5. You can reach him at richard.rickman@townsquaremedia.com

Click here to contact an editor about feedback or a correction for this story.

LOOK: 31 breathtaking images from NASA's public library

In 2017, NASA opened the digital doors to its image and video library website, allowing the public to access more than 140,000 images, videos, and audio files. The collection provides unprecedented views of space. Stacker reviewed the collection to select 31 of the most breathtaking images, including the first from the James Webb Space Telescope. Keep reading to see these stunning images, curated with further information about the captured scenes.

LOOK: These Are the 50 biggest retailers in America

Stacker compiled a list of the 50 biggest retailers in the country, using retail sales data from Kantar, provided by the National Retail Federation.

Cape May, NJ: 15 wonderful places to visit