Big Beef, Inc. raises calves to sell. Big Beef breeds its cows in April, and the cows calve in February of the following year. In January Andrea contracts with Big Beef to buy fifty calves. Identification takes place in

April, after the conception of the calves

Explanation:

When the calves are conceived, certain features are necessary for identification to ensure that the right calves are selected. Since Big Beef, Inc. raises calves to sell, they must ensure that the calves bought, go through a good hygienic birth and have the needed milk from the cow, which shows on the calves as they grow stronger and healthier.

Since Andrea contracts with Big Beef to buy fifty calves and the cows breed in April, then identification can take place after the breeding of the cows. By that time, the calves would have been conceived.