Environmental concerns regarding genetically modified animals

Written by Administrator

Friday, 10 July 2009 06:09

No GM animals are currently being used in commercial agriculture anywhere in the world (Chapter 2), but several livestock and aquatic species are under research for a variety of transgenic traits. Studies of the potential environmental concerns associated with GM animals have been conducted recently by the United States National Research Council (NRC, 2002), the United Kingdom Agriculture and Environment Biotechnology Commission (AEBC, 2002) and the Pew Initiative on Food and Biotechnology (Pew Initiative, 2003). These studies conclude that GM animals may have either positive or negative effects on the environment depending on the particular animal, trait and production environment in which it is introduced. The main environmental concerns associated with animals involve: (a) the possibility that transgenic animals could escape with resultant negative effects on wild relatives or ecosystems, and (b) potential changes in production practices that may lead to varying degrees of environmental stress. These reports recommend that GM animals should be evaluated in relation to their conventional counterparts. The three studies agree that transgenic animals should be evaluated for their ability to escape and become established in different environments. The NRC and AEBC agree that adverse environmental impacts are less likely for livestock breeds than for fish, because most farm animal species have no wild relatives remaining and farm animal reproduction is confined to managed herds and flocks. The danger of becoming feral is low in cattle, sheep and domestic chickens, which are less mobile and highly domesticated, but higher in horses, camels, rabbits, dogs and laboratory animals (rats and mice). Non-transgenic domestic goats, pigs and cats have been known to become feral, causing extensive damage to ecological communities (NRC, 2002). Transgenic farm animals would be particularly valuable and therefore would be kept in carefully controlled environments. Aquacultured fish, by contrast, are naturally mobile and breed easily with wild species. The AEBC report recommends that transgenic fish should not be raised in offshore pens owing to the high probability of escape. The Pew Initiative study points out that the impact of escaped aquaculture fish, whether transgenic or conventionally bred, depends on their “net fitness” compared with wild species. It argues that transgenic traits could increase or decrease the net fitness of farmed species, and recommends that transgenic fish be carefully evaluated and regulated in an integrated and transparent way. Transgenic animals could also lead to environmental impacts through changes in the animals themselves or in the management practices associated with them. Transgenic modifications could reduce the amount of manure and methane emissions produced by livestock and aquaculture species (AEBC, 2002; Pew Initiative, 2003) or increase their resistance to diseases (promoting lower antibiotic usage). On the other hand, some genetic modifications could lead to more intensive livestock production with associated increases in environmental pollutants. The question of environmental harm is therefore less a question of the technology itself than of the capacity to manage it. An additional factor to consider with livestock biotechnology is the possible effects on the welfare of animals. These welfare effects may be positive or negative and should be evaluated against conventional livestock management practices (AEBC, 2002). At present, the production of transgenic and cloned animals is extremely inefficient, with high mortality during early embryonic development and success rates of only 1-3 percent. Of the transgenic animals born, the inserted genes may not function as expected, often resulting in anatomical, physiologicaland behavioural abnormalities (NRC, 2002). Cattle produced by cloning methods tend to have longer gestation periods and higher birth weights, resulting in a higher rate of Caesarean births (NRC, 2002; AEBC, 2002). Such problems can also occur with animals produced using AI/MOET, and should be evaluated in the context of the other reproductive technologies used in livestock production (AEBC, 2002). The AEBC report further recommends that the potential welfare effects of all technologies used in animal agriculture should be weighed against economic and environmental considerations.

Last Updated on Friday, 10 July 2009 09:00