Some evidence indicates that keeping an animal safe and limiting its stress can lead to better-quality meat and milk; there are various scientific reasons for this which are not particularly well-understood, involving the impact of enzymes created in times of stress on muscle tissue, or, in the case of dairy cows, reducing their output of milk.
One new bit of evidence is a little bit clearer, since it doesn’t actually involve making animals happier: just tricking the animal into thinking it is.
Bovine somatotropin (bST), also known as bovine growth hormone, is an animal drug approved by FDA to increase milk production in dairy cows. This drug is based on the somatotropin naturally produced in cattle.
Somatotropin is a protein hormone produced in the pituitary gland of animals, including humans, and is essential for normal growth, development, and health maintenance.
Early research in the 1930s and 1940s in Russia and England found that milk production in cows could be increased by injecting cattle pituitary extracts, specifically bST.
English scientists attempted to increase milk production in cows during World War II with pituitary-derived bST to alleviate food shortages.
However, it wasn’t until the 1980s that it became technically possible and economically feasible to produce large commercial quantities of bST by a process using biotechnology
The FDA approves an animal drug only after information and/or studies have shown that the food (in this case, milk and meat) from the treated animals is safe for people to eat, and that the drug does not harm treated animals, or the environment. The drug also must be effective, meaning that it works as intended