They never sent it to Ames, Iowa. They sent it ONLY to USAMRIID.
In late 1980, Dr. Gregory B. Knudson, a biologist working at the Army's biodefense laboratory at Fort Detrick, Md., was searching for new anthrax strains to use in tests of the military's vaccine. In December 1980, he wrote Texas A&M to see if they had any new anthrax strains. They didn't have anything at the time, but in early 1981, they received a sample of anthrax that had been extracted from a cow that had recently died. So, Texas A&M forwarded a portion of that sample to Ft. Detrick.
However, because Texas A&M frequently sent such samples to the USDA in Iowa, they had postage-paid labels from the USDA and they used one of the USDA labels, simply pasting the Ft. Detrick address over the USDA address. (It was evidently a way of saving a few dollars for Texas A&M.) And, when the sample arrived at Ft. Detrick, Dr. Knudson called it "The Ames Strain" because the mailing label indicated the sample had come from Ames, Iowa.
The Ames strain never went to Iowa - much less to ISU.