AmerisourceBergen Corp., a U.S. drug distributor, agreed to buy MWI Veterinary Supply Inc. for $2.5 billion to add fast-growing animal-health supplies.

Amerisource will offer $190 a share in cash for Boise, Idaho-based MWI, the companies said in a statement today. The price is 8.2 percent above the closing level for MWI on Jan. 9.

The purchase will add about 8 cents a share this year to earnings at Valley Forge, Pennsylvania-based Amerisource, the company said. Sales of veterinary products are increasing as people spend more on pets and eat more meat, boosting demand for animal feed and medicines.

“Animal health is a growing market in the U.S. and internationally, and is a logical extension of our pharmaceutical-distribution and services businesses,” Amerisource Chief Executive Officer Steven Collis.

BofA Merrill Lynch acted as financial adviser, and Cravath, Swaine & Moore LLP provided legal advice to AmerisourceBergen. JPMorgan Chase & Co. acted as financial adviser, and Dechert LLP provided legal advice to MWI.