title: Genetic engineering of livestock.
abstract: Genetic engineering of livestock is expected to have a major effect on the agricultural industry. However, accurate assessment of the consequences of transgene expression is impossible without multigenerational studies. A systematic study of the beneficial and adverse consequences of long-term elevations in the plasma levels of bovine growth hormone (bGH) was conducted on two lines of transgenic pigs. Two successive generations of pigs expressing the bGH gene showed significant improvements in both daily weight gain and feed efficiency and exhibited changes in carcass composition that included a marked reduction in subcutaneous fat. However, long-term elevation of bGH was generally detrimental to health: the pigs had a high incidence of gastric ulcers, arthritis, cardiomegaly, dermatitis, and renal disease. The ability to produce pigs exhibiting only the beneficial, growth-promoting effects of growth hormone by a transgenic approach may require better control of transgene expression, a different genetic background, or a modified husbandry regimen.
authors.affiliation: U.S. Department of Agriculture, Beltsville, MD 20705.
authors.forename: V G
authors.initials: VG
authors.lastname: Pursel
authors.forename: C A
authors.initials: CA
authors.lastname: Pinkert
authors.forename: K F
authors.initials: KF
authors.lastname: Miller
authors.forename: D J
authors.initials: DJ
authors.lastname: Bolt
authors.forename: R G
authors.initials: RG
authors.lastname: Campbell
authors.forename: R D
authors.initials: RD
authors.lastname: Palmiter
authors.forename: R L
authors.initials: RL
authors.lastname: Brinster
authors.forename: R E
authors.initials: RE
authors.lastname: Hammer
mesh_terms: D000383:Agriculture; D000818:Animals; D000829:Animals, Domestic / Q000235:genetics* / Q000254:growth & development; D030801:Animals, Genetically Modified; D001835:Body Weight; D005260:Female; D005818:Genetic Engineering; D013006:Growth Hormone / Q000235:genetics; D013007:Growth Hormone-Releasing Hormone / Q000235:genetics; D007334:Insulin-Like Growth Factor I / Q000235:genetics; D051379:Mice; D009929:Organ Size; D013552:Swine / Q000235:genetics / Q000254:growth & development; D014162:Transfection
chemical_list: D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone