Farm animals are important biomedical models

This issue of Animal Frontiers, “Farm animals are im- portant biomedical models,” describes several examples in which cattle, sheep, pigs, or chickens provide an excellent physiological model for studies related to human health or disease (Figure 1). While previous reports have discussed the use of domestic animals as dual-purpose models that benefit agricultural and biomedical research (Ireland et al., 2008), this issue of Animal Frontiers provides additional and novel examples of the value of farm animals for biomedical re- search. Because farm animals are larger in size than labora- tory species, scientists are able to collect larger volumes and more frequent samples of blood without significant changes in blood chemistry or substantive changes in blood volume as well as larger or more frequent tissue biopsies, thereby al- lowing the study of changes in hormones, metabolites, im- mune factors, or cellular components in the same animal over time. Many of these studies revealed that the physiology of humans is more closely related to the physiology of farm ani- mals than to rodents. Finally, the human genome sequence is more similar to the genome sequences of cattle and pigs compared with rodents (Humphray et al., 2007; Tellam et al., 2009); thus, cattle and pigs may be better models for many human genetic diseases