title: Clinical and pathologic features of cloned transgenic calves and fetuses (13 case studies).
abstract: The neonatal abnormalities, treatments and outcomes in a group of 13 cloned transgenic calves and fetuses that progressed into the third trimester of pregnancy are described. From these 13 fetuses, 8 calves were born live, 4 stillborn fetuses were recovered from 3 cows that died 7 d to 2 mo before term, and 1 aborted fetus was recovered at 8 mo gestation. All fetuses and calves were derived from the same male fetal Holstein fibroblast cell line transfected with a beta-galactosidase marker gene. Six calves were delivered by Cesarian section and two by vaginal delivery between 278 and 288 d of gestation. Birth weights ranged from 44 to 58.6 kg. Five of the 8 live born calves were judged to be normal within 4 h of birth based on clinical signs and blood gas measurements. One of these 5 calves died at 6 wk of age from a suspected dilated cardiomyopathy. Three of the 8 calves were diagnosed with neonatal respiratory distress immediately following birth, one of which died (at 4 d of age) as a result of pulmonary surfactant deficiency coupled with pulmonary hypertension and elevated systemic venous pressures. Similar findings of chronic pulmonary hypertension were also observed in 2 of 5 fetuses. Placental edema was present in both calves that later died and in the 2 fetuses with cardiopulmonary abnormalities. Hydrallantois occurred with or without placental edema in 6 cows, and only 1 calf from this group survived. The 6 cows without hydrallantois or placental edema produced 5 live calves and 1 aborted fetus. The cardiopulmonary abnormalities observed in the calves and fetuses occurred in utero in conjunction with placental abnormalities, and it is likely that the cloning technique and/or in vitro embryo culture conditions contributed to these abnormalities, although the mechanism remains to be determined.
authors.affiliation: College of Veterinary Medicine, Texas A&M University, College Station 77843-4475, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Hill
authors.forename: A J
authors.initials: AJ
authors.lastname: Roussel
authors.forename: J B
authors.initials: JB
authors.lastname: Cibelli
authors.forename: J F
authors.initials: JF
authors.lastname: Edwards
authors.forename: N L
authors.initials: NL
authors.lastname: Hooper
authors.forename: M W
authors.initials: MW
authors.lastname: Miller
authors.forename: J A
authors.initials: JA
authors.lastname: Thompson
authors.forename: C R
authors.initials: CR
authors.lastname: Looney
authors.forename: M E
authors.initials: ME
authors.lastname: Westhusin
authors.forename: J M
authors.initials: JM
authors.lastname: Robl
authors.forename: S L
authors.initials: SL
authors.lastname: Stice
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000831:Animals, Newborn / Q000502:physiology*; D002245:Carbon Dioxide / Q000097:blood; D002318:Cardiovascular Diseases / Q000662:veterinary; D002417:Cattle / Q000196:embryology*; D002418:Cattle Diseases; D019976:Cloning, Organism; D005260:Female; D005313:Fetal Death / Q000662:veterinary; D008297:Male; D010100:Oxygen / Q000097:blood; D010922:Placenta Diseases / Q000662:veterinary; D011247:Pregnancy; D011256:Pregnancy Outcome
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen