Living things can be turned into pharmaceutical 'bioreactors' by adding genes that code for commercially useful proteins. Transgenic pharm bacteria and plants are the simplest to create, but animals are often used to manufacture complex products. The chief advantage of animals is their ability to produce more than one protein at a time. They are also easier to control than plants (which are more likely to inadvertently hybridize with other species) and do not require the complex processing vats required by bacteria.
Pharm animals are designed so that products can be extracted safely by tapping or harvesting blood, milk, saliva, urine, eggs, or even cheese. While the gengineering involved is intricate, the maintenance and processing is low-tech, making pharm animals (especially fertile ones) favorites for start-up colonies and developing nations. Paralleling earlier struggles over genemod crops, conflicts often arise between biotech companies who wish to restrict their products' ability to reproduce and customers who want cheap, self-reproducing livestock. Various restrictions are used, such as trademarks embedded into the genetic code, sterilization, or special hormones required before fertility. Similarly, genehacked pharm animals without these restraints sell well on the black market.
Simple pharm animals include cows that produce additive-enhanced baby formula or vaccines, or pigs with human hemoglobin in their blood (to serve as blood substitute). Others possess internal symbiotic microbes that let them produce ready-to-use designer drugs, industrial proteins, or even explosives. Pharm animals were extensively used by the anti-government forces during the Andes War, where genemod goats and llamas manufactured strategic products such as combat drugs, medicines, bomb components, and the spider silk used for arachnoweave armor. Pharm animals used in space colonies often have pantropic modifications to better adapt to extraterrestrial environments.
A variation on the pharm animal is the use of implanted nanofactories to make particular chemicals. Pharm humans are also possible, but rarely considered ethical. A few exotic bioroids do have built-in drug factories.