Producing embryos via in vitro techniques and then transplanting them to cattle dramatically increases the rate of hydrops; one large study found 1 case of hydrops in 200 IVP (in vitro production) pregnancies in cattle, or a rate of 0.5% (Hasler et al. 1995). With SCNT clones, the risk of hydrops is far larger than even the case of IVP. The FDA identified 8 studies in the scientific literature that looked at rate of hydrops in SCNT clones; 3 of these studies involved animals that were transgenic and/or SCNT (Table V-2, FDA 2006). The rate of hydrops varies in these studies from 13% (1 of 8) (Batchelder 2005) to 42% (18 of 43) (Wells et al. 2003). If we pool all the studies together, the rate of hydrops for SCNT is 21.3% (66 of 310); if we exclude the transgenic clones, the rate increases slightly to 28.9% (33 of 118). Thus, the rate of hydrops is more than 50 times higher in SCNT births compared to IVP births ( 28.9% and 0.5%, respectively) and more than 216,800 times higher than the rate in the general cattle populations. This is a phenomenally large increase in a problem that can cause difficult births and cause health problems to both the surrogate carrying the SCNT clone as well as the SCNT clone itself. Some of these health problems could require medical intervention that involves drugs.
In the Cyagra data set on SCNT cow clones, difficult births were quite common. Some 45% of the animals investigated (26 of 58) had umbilical surgery, usually to close enlarged umbilical vessels that don’t close naturally. The surgery is done to prevent complications such as umbilical infections and bleeding. Any animals with umbilical infections and bleeding would have to be treated with antibiotics and other drugs.
For pigs, there is far less data on health. Pigs produced using SCNT do not appear to be susceptible to LOS, but they still appear to suffer from health problems associated with weakened immune system. A Korean study found that that 63% (22 of 35) of live born SCNT piglets died within the first week of life (Park et al. 2005). Health problems in these animals included inflammation of a brain membrane and sever congestion in the lungs and liver. Many of the clinical symptoms described are similar to those caused by various bacterial diseases common in the pig industry. In addition, a number of the piglets were described as being born weak.
A study carried out by scientist at the University of Connecticut found that even adult SCNT clones can die suddenly (Lee et al., 2003). In the study, 4 cloned piglets were born and one died within days. The other three pigs died unexpectedly of heart failure just before reaching 6 months of age. Dr. Jerry Yang, who led the research stated that “ ‘It was totally shocking,’ says Yang. He has dubbed the fatalities ‘adult clone sudden death syndrome’ “ (Pearson, 2003, available at http://www.nature.com/nsu/030825/030825-2.html). Since pigs are often sold to the markets at 5 months of age, this shows that adults can experience health problems.
There definitely is the possibility of indirect safety effects that are the result of cloning. For example, if the immune system of the clone is impaired, as a number of studies suggest, then such animals may be more susceptible to disease and/or stress which could result in the need for more medications (such as antibiotics) to treat such diseases. There have been reports in the literature that cloned calves, lambs, goats and pig have