The following is an excerpt of a post by Heidi Carroll and Michael Gonda of the South Dakota State University Extension, originally posted to

Genetic technologies have major impacts on food animal farming and ranching.

Genetic Engineering

Genetic engineering (GE) refers to the insertion, deletion, or modification of a specific region of DNA in an organism. This technology has the potential to transform how we improve livestock with genetics. The benefits of GE to agriculture, animals, and our environment are numerous and include:

  • Increasing agricultural productivity (more food for more people in our community and elsewhere)
  • Improving animal welfare (animals able to adapt to changing environments and weather)
  • Increasing disease resistance (improves animal health to use fewer antibiotics)
  • Improving environmental sustainability (animals use fewer resources to produce our food).

Recent use of GE in research animals has resulted in pigs that are resistant to Porcine Reproductive and Respiratory Syndrome (PRRS) virus and Holstein cows without horns. Breeding Holstein cows without horns improves animal welfare by eliminating the need for dehorning, which also improves human safety.

Genetically Engineered (GE) Foods

Scientists have studied GE organisms for decades and have demonstrated that this technology is completely safe. Genetically engineered crops for human and animal consumption have been on the market for many years, and GE livestock have been developed for research purposes since the 1980’s. The National Academies of Sciences, Engineering, and Medicine found no difference in risks to human health or the environment from using GE crops when compared to non-GE crops. All animals possess DNA, which is a biological language (or code) that directs cells to complete tasks necessary for life (e.g., movement, breathing). The alphabet for the language of DNA is composed of four “letters”: A, C, G, and T. Genetic engineering adds, deletes, or changes the sequence of these “letters” in DNA. The only change made to GE animals is a change in this biological code. A good analogy to DNA is a computer program, which directs a computer to carry out functions defined in its code. Genetic engineering is changing the biological code (DNA) of an animal, similar to how a computer programmer changes a computer code so that the computer can carry out a different task.

However, just like genetic selection without the use of GE, the potential for unintended consequences of specific applications of GE to livestock needs to be evaluated. For example, researchers in the 1980’s modified pigs to produce excess growth hormone, which did increase muscle mass. Unfortunately, the excess growth hormone had adverse effects on survival and welfare, so this research was discontinued. The US government rigorously evaluates the impact of all GE livestock on the environment and the welfare of the animals themselves. A complete and stringent approval process for GE livestock is essential to gain the public’s trust in the application of this technology to improve animal welfare, disease resistance, food yield, and environmental sustainability of animal agriculture. We must also remember that traditional genetic selection without the use of GE can also result in unintended consequences on animal welfare (e.g., lameness in broilers selected for growth rate, fertility problems in dairy cattle selected for high milk yield, etc.). Once identified, steps were taken to correct these problems. Yet, if genetic selection was never practiced, it would be difficult to envision how the meat and dairy yields taken for granted today could have been achieved. The risks of using GE livestock are no different than using conventionally raised livestock, yet the benefits to agriculture, the environment, and society may be enormous.

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