Giving birth on an airplane is a relatively rare occurrence, but the odds were stacked on a flight earlier this month that left California with 50 passengers and arrived in Honolulu with 51.

The Sept. 3 charter flight of Pacific Airlift Inc. was carrying 50 pregnant cows for local milk producer Island Dairy.

"It wasn't like a total shock," Island Dairy herd manager Adam Beard said of the birth.

All the cows were about eight months pregnant, but Beard said stress from flying can sometimes induce calving before a cow's roughly nine-month gestation period is up.

The early arrival was named Air-born.

Beard said the bull calf will be raised to further expand the herd.

Island Dairy arranged the Pacific Airlift flight as part of a strategy to expand local milk production and its herd.

Mainland dairies struggling in the slack economy have made cows available at attractive prices, and acquiring pregnant cows helps expand milk production and grow the herd more quickly for Island Dairy.

Beard said a flight with 40 more pregnant cows is scheduled to arrive tomorrow.

Over the past two years, the Big Island-based company has more than doubled its herd, and now milks about 700 cows. The company's goal is to have 1,000 cows by the end of next year if it can sell local milk through more retailers.

In February, Island Dairy began supplying Foodland Super Market and Sack N Save stores statewide with its Hawaii's Fresh brand milk. The move represented the first time in several years that O'ahu, Maui and Kaua'i residents could buy local milk in stores.

Island Dairy said Whole Foods Market, which operates one O'ahu store and plans to open two more next year on Maui and O'ahu, will carry its local milk starting next week.

A string of local dairy shutdowns in recent years left residents of O'ahu, Maui and Kaua'i with all their milk imported from the Mainland. Island Dairy and one other surviving dairy business on the Big Island supply fresh local milk on that island.