Table I.
The advantages and disadvantages of the pig as a potential source of organs and cells for humans, in contrast with those of the baboon in this role
| Pig | Baboon | |
|---|---|---|
| Availability | Unlimited | Limited |
| Breeding potential | Good | Poor |
| Period to reproductive maturity | 4–8 months | 3–5 years |
| Length of pregnancy | 114 ± 2 days | 173–193 days |
| Number of offspring | 5–12 | 1–2 |
| Growth | Rapid (adult human size within 6 months)a | Slow (9 years to reach maximum size) |
| Size of adult organs | Adequate | Inadequateb |
| Cost of maintenance | Relatively low | High |
| Anatomical similarity to humans | Moderately close | Close |
| Physiological similarity to humans | Moderately close | Close |
| Relationship of immune system to humans | Distant | Close |
| Knowledge of tissue typing | Considerable (in selected herds) | Limited |
| Necessity for blood type compatibility with humans | Probably unimportant | Important |
| Experience with genetic engineering | Considerable | None |
| Risk of transfer of infection (xenozoonosis) | Low | High |
| Availability of specific pathogen-free animals | Yes | No |
| Public opinion | Generally in favor | Mixed |
aBreeds of miniature swine are ∼50% of the weight of domestic pigs at birth and sexual maturity, and reach a maximum weight of ∼30% of standard breeds.
bThe size of certain organs, e.g., the heart, would be inadequate (too small) for transplantation into adult humans.
Reproduced with permission from Cooper and Bottino (2015).