We still use swine thyroid for thyroid hormone replacement. The most familiar US brand is Armour. The meatpacking company.

The parade example of a female hormone replacement agent —conjugated estrogens—is known by the brand name Premarin, because it comes from PREgnant MAre uRINe. Before a good system was developed to harvest horse urine, there were early estrogen products (1930s) made from pregnant human urine.

Human Growth Hormone can now be produced using recombinant DNA tools, but the earliest treatments for growth hormone deficiency were developed by harvesting the pituitary glands from cadaver humans. Animal growth hormones never worked in humans.

Bovine and porcine sources for insulin are still used in some parts of the world.