By creating herds of cloned animals that have the same genetic composition, either entirely or with respect to some particular traits, the diversity of those animals is significantly reduced. As a consequence, cloned animals and herds may be more susceptible to disease and less able to withstand an outbreak. This could have serious repercussions for the population as a whole and for the agriculture industry.
The range of potential environmental impacts associated with the proliferation of cloned animals has not been thoroughly investigated and is largely unknown and uncertain.
Resources Turner, J. (2002). The Gene and the Stable Door: A Report for the Compassion in World Farming Trust.