These effects are not from BST injection per se, but are related to the increased milk produc-tion levels and the additional energy demands that the cow requires to meet those levels. Work remains to be completed to determine the optimal times during the lactation cycle that individual cows should be eligible for BST administration. Prior to the possibility of BST usage, it was believed that the optimum interval between calvings for a cow was one year. With BST usage, cows may maintain milk production at profitable levels much longer. The optimum calving interval under BST usage is not known.
Some consumers prefer milk from non-treated cows.
Certain milk bottlers are providing milk that is certified to be from non-treated cows. Certification can be achieved only by the pledge of the dairy producer, since no method is available to detect whether milk is from a treated cow. It is unclear how much additional money consumers are willing to pay. What We Are Doing We are monitoring the scientific literature and providing unbiased and science-based information about any potential impacts of BST usage on food safety and human health, animal well being, and safety of the environment.