Agro-Biotechnology: - The Greens | European Free Alliance

14 | Cloned farm animals - a ‚killing application‘? | Technical problems
The most sensitive life period of cloned cattle seems to end at the age of six
months. As FDA (2008) concludes:
“During the juvenile period (up to approximately six months of age), bovine
clones continue to be at an increased risk of morbidity or mortality compared
to animals produced by natural service or ARTs 16 . Estimates of mortality
during this period range from 14 to 42 percent. These deaths appear to be sequelae
of the initial developmental abnormalities noted in the perinatal node
that persist into the juvenile period (e.g. musculoskeletal defects, prolonged
recumbency, enlarged umbilicus, respiratory distress, poor thermoregulation,
cardiovascular failure, gastroenteritis).”
Most cattle surviving to that age seem to be healthy. But open questions remain,
since the parameters for meat and milk composition, blood parameters,
and the level of gene expression are reported to be partially different from
the parameters of cattle stemming from sexual propagation (for overview see
Center for Food Safety, 2007). In some cases health problems in adult animals
have also been reported (FDA, 2008, EFSA, 2008a). According to EFSA (2008a)
the question of immunocompetence and the susceptibility of clones and their
offsprings to diseases and transmissible agents under practical conditions also
needs further investigation.
The FDA (2008) also mentions the immune system as potentially affected by
the SCNT process. The US authority refers for example to investigations by
Ogonuki et al. (2002) and Ogura et al. (2002), that show immune disorders and
severe respiratory health problems in mice derived from certain donor cells.
So far only very few studies concerning animal health over whole life spans
have been published. Remarkably, FDA (2008) even states that in the case of
sheep there have been no published reports on the health status of live sheep
clones since Dolly. Since most farm animals are used for the production of
meat, it might be a challenge to identify the right scientific approach for investigating
their life span and related animal health problems. As FDA (2008)
states:
“Currently, it is not possible to draw any conclusions regarding the longevity
of livestock clones or possible long-term health consequences associated with
cloning due to the relatively short time that the technology has existed."
16 Assisted reproduction technologies such as embryotransfer