Agro-Biotechnology: - The Greens | European Free Alliance

Technical problems | Cloned farm animals - a ‚killing application‘? | 13
Many of the observed adverse health impacts are summarised as Large Offspring
Syndrome (LOS). Some effects of LOS are also observed, but at a much
lower rate, in animals derived from embryo transfer in cattle and sheep (EFSA
2008a, FDA, 2008). LOS has been especially observed in clones from species
of cattle and sheep. They often go together with late gestation and give rise to
an increase in perinatal deaths, excess foetal size, abnormal placental development
(including an increased incidence of hydrops 13 ), enlarged internal organs,
increased susceptibility to disease, sudden death, reluctance to suckle and
difficulty in breathing and standing. (EFSA 2008a)
In sheep, cows and mice the following problems were detected (Gjerries &
Vatja, 2005):
• Placental abnormalities
• Foetal overgrowth, prolonged gestation
• Stillbirth, hypoxia, respiratory failure and circulatory problems, lack of
post-natal vigour
• Increased body temperature at birth
• Malformations in the urogenital tract
• Malformations in liver and brain
• Immune dysfunction, a malformation of related organs
• Bacterial and viral infections
In contrast to the LOS syndrome observed in cattle and sheep clones, pigs produced
by SCNT are more likely to show an increased incidence of intrauterine
growth retardation and reduced weight at birth. (EFSA 2008a, FDA, 2008)
There is a lack of understanding of the underlying mechanisms and also there
is no coherent definition for LOS. The observers agree that these effects are
mostly relevant for the intrauterine 14 , the perinatal 15 and the neonatal period.
But at a later stage in the first three to six months a high incidence of health
implications has been observed by many authors. All these effects contribute
finally to a low overall rate of success. This low rate of success is also shown in
some of the publications cited by EFSA (2008a) or Gjerries & Vatja (2005):
Panarace et al. (2007): of 3374 embryo clones transferred into surrogate dams,
317 (9 percent) live calves were born, 24 hours after birth 278 of these clones
(8 percent) were alive, and 225 (7 percent) were alive at 150 days or more
after birth.
Wells et al. (2004): of 988 bovine embryo clones transferred into recipient
cows, 133 calves were born and 89 (67 percent) of them survived to weaning
at three months of age.
13 Abnormal accumulation of fluid
14 during pregnancy
15 time before and after birthing