The Tragic Sudden death of 21 Polo Ponies

Hello Folks,
This week, I have been following various news articles about the tragic and mysterious sudden deaths of 21 Polo ponies in Wellington, Florida.

Now I may have spent most of my lifetime around horses, but really have to say that I have never heard of anything quite like this before.
If you are unaware of this news story, please see here for further details, The Telegraph also reported that:
"The team is owned by Victor Vargas, a Venezuelan businessman, close confidant of Hugo Chavez and one of the richest men in South America"


On April the 20th, The Polo Association stated that:

"The cause of death for these horses will not be determined until after the Florida State Department of Agriculture completes necropsies and toxicology testing on the affected animals. There has been much speculation and rumor concerning the cause of death however, according to Dr. Paul Wollenman, who was on the scene and led a valiant rescue effort with many local veterinarians and polo players to save the stricken horses: 'Based on initial, overwhelming clinical evidence this medical event was isolated to the Lechuza barn and horses and the initial evidence shows no infectious element.'

Today (22/4/09) CBS news stated that:

“(CBS) CBS4's Gwen Belton has the latest on the mysterious death of 21 Venezuelan polo ponies who died on the eve of a polo championship in Florida.

A Venezuelan team official reported on Wednesday that all 21 of its polo ponies set to compete at the U.S. Open Polo Championship were injected before the game with a vitamin supplement called Biodyl.

The team contends a tainted dose may have caused their deaths. Florida state officials have since opened an investigation to determine the cause of death”

Even if this explanation proves to be true, I still cannot understand why a vitamin injection would be administered, just before the event ?