died of bacterial infection and sudden death of unknown cause in the neonatal period (Carroll et al., 2005).
More recently, scientists at the University of Missouri evaluated the innate immune response (via measurements of cortisol and two cytokines—tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6) of 9 cloned pigs (from two different cell lines) compared to11 genetically similar non-cloned pigs exposed to an endotoxin (lipopolysaccharide). Before the study began, the cloned pigs had lower levels of cortisol and TNF-alpha. They found that the cloned pigs had a weaker immune response to the endotoxin, with levels of cortisol, TNF-alpha and IL-6 all lower, sometimes dramatically so, in the cloned pigs compared to the non-cloned comparators, suggesting the clones had a crippled immune system (Carroll et al., 2005). As the lead researcher, Dr. Jeff Carroll said, “I’ve looked at the immune response of hundreds of young pigs and I’ve never seen anything that low until I looked at a clone” (Anon., 2005: 20). The researchers call for “further investigation of the immune system of cloned animals” (Carroll et al. 2005: 564). Interestingly, FDA, despite their extensive review of the literature failed to mention the work of Carroll et al. (2005), even though it was funded by USDA.
In a review of cloning, New Zealand researcher notes that “any underlying frailties in cloned animals may not be fully revealed until the animals are stressed in some manner” (Wells, 2005: 2??). Such underlying frailties or weakened immune systems, as suggested by work with mice, cows and pigs, means that such animals may have to be treated with drugs. In addition, drugs, including various hormones, often have to be administered to the surrogate animals to help the surrogate carry the clone fetuses to term.
In sum, the data on cattle show that they are very susceptible to health problems that could increased the need for drugs, especially antibiotics and hormones. The LOS occurs in more than 50% of the SCNT cow clones compared to 0.00013% (1 in 7,500) in the general cattle population. LOS cattle and sheep are more susceptible to infections which means that more antibiotics could be given to them. The large size of LOS clones means that they are often delivered by cesarean section with application of exogenous corticosteroids (Wells et al., 1999). Thus, for cattle and sheep, where LOS is a problem, increased use of drugs, especially hormones, are often used on the surrogates that carry of clones. Thus could lead to increased levels of these hormones and other drugs in the carcasses of the animals.
In pigs, the data clearly show them to have weakened immune systems. Thus, the studies involving pigs and cattle clearly show them to be an increased risk of infectious diseases that would necessitate use of antibiotics and other drugs. This would probably lead to increased use of antibiotics in both cattle and pig production. At the same time, there is huge problem at present with the overuse of antibiotics in US animal production; anything that would significantly increase use of antibiotics, such as widespread use of SCNT clones should be discouraged. FDA should not allow SCNT clones on the market until the question of increased use of antibiotics and other drugs in the production of