At Recombinetics, a company which specializes in genetic modifications, including that of livestock, naturally hornless — or polled — Holsteins are one of the selected traits which they’ve been able to produce via gene editing techniques.
Dehorning cattle is going to become one of the primary issues facing the dairy and beef industry in the near future, Dr. Jen Burton, veterinarian for Organic Valley CROPP Cooperative, predicted last year.
Gene editing could be one way to save livestock from painful procedures such as dehorning. This type of genomic alteration is called subgenic, and doesn’t involve genes from other species, but is simply a manipulation of the animal’s genetic material working within the available genetic material from the same species.
According to Recombinetics website: “Recombinetics currently uses tools like TALENs and CRISPR/Cas9, which act as ‘molecular scissors’ to precisely cut into DNA to remove genes and replace (introgress) them with better ones from the same species.”
Gene editing requires precise knowledge of the species genome, and manipulation of that material, which results in the expression of a given trait. Gene editing can result in different traits which enhance animal and environmental well being, such as: disease resistance, decreasing mortality, antibiotic use or animal illness; enhanced productivity, decreasing food costs and enhancing sustainable production; or sex selection, reducing unwanted animals and decreasing their welfare concerns.
This isn’t the type of transgenic genetic engineering — genomic modifications involving genes from a different species — that many people think of when concerns about genetically modified food arises. Traditional breeding could ultimately yield the same results as subgenic modification, but would take a much longer time period, and might inadvertently result in the expression of non-desired traits.
“Genetic selection has had a tremendous impact improving livestock productivity,” Michael Gonda, PhD, Associate Professor, Department of Animal Science, University of South Dakota, said. Traditional breeding has enhanced productivity, but often inadvertently caused “deleterious” effects.
Gonda discussed the animal welfare impacts of genetic engineering of livestock in a recent webinar, “21st Century Technology and Its Impact on Animal Welfare.”
The early emphasis on breeding for milk yield and milk fat in the dairy industry was one contributor to an increase in animal welfare concerns including lameness, mastitis and a decrease in daughter pregnancy rate. In the past decades, the industry has worked to refocus on many more traits, not simply milk production, and an increase in animal health and welfare has occurred.
Selective breeding via traditional methods has also caused issues in other species. Poultry have been bred to have too much breast size and suffer from lameness. Angus cattle were once selected for productivity, with a resulting negative impact on fertility, pregnancy rate and other health-related traits. But recent years have seen expanded traits becoming important, improving overall cattle health.
There has been “deleterious impacts on animal welfare, fertility, and health of the animals just through traditional genetic selection,” Gonda said. “Today, we have gone back and made significant progress… just going back and improving” some of the negative effects which resulted via natural breeding techniques.
Traditional genetic selection doesn’t pinpoint exactly which genes are being altered. It can take years to see the results — both positive and negative. Unlike traditional genetic selection, genetic modification requires precise knowledge of the genetic material, and what traits are being altered.
Genetic modification enables us to “get a DNA estimate of genetic merit on traits that are difficult to read on farm, but are related to animal welfare,” and avoid concerns that can arise when breeding for a given trait, Gonda said. “You have to know what genes you are going to modify.”
Modifying the phenotype is much faster with genetic modification than via traditional methods. And, the phenotype can be altered in ways that may never be able to be accomplished via traditional methods. The potential to increase productivity, increase the sustainability of animal agriculture, and to decrease disease and illness in livestock, via genetic modification, exists, he said.
There are genetically modified livestock today: it is a reality. Genetically modified animals run the gamut from animals designed to have healthier fatty acid profiles in their meat to mastitis resistant cattle.
“The concept of GMO is not new, it’s just new to the livestock industry,” Gonda said, noting that crops have been genetically modified for decades.
While there are not any genetically modified livestock in the market in the United States, the FDA has approved AquAdvantage® Salmon, which is genetically engineered. The fish contain a growth hormone from the Chinook salmon, which was inserted into the genome of the Atlantic Salmon, causing faster growth. This reduction in time to market is meant to decrease sustainability issues, meet a growing demand for protein, and help keep production costs down.
In swine, a gene known CD163 has been deleted, resulting in hogs resistant to Porcine Reproductive and Respiratory Syndrome (PRRS), a viral disease. The virus can’t reach the host without the gene, so no pigs become ill, enhancing animal welfare. In beef cattle, the prion protein which causes Bovine spongiform encephalopathy (BSE) has been eliminated via genetic engineering, too, enhancing animal and human health. There’s even a pig whose genome has been modified to produce less phosphorous in its feces.
Despite the negative headlines, and intense controversy, which genetic modification has caused, “it’s not all just negative… There’s a lot of positive that can come from the genetic engineering of livestock. The technology of GMOs for engineered livestock is completely safe,” Gonda said. “You do, like anything, have to watch for unintended consequences. You do still need very stringent regulations, and an approval process from the FDA… to do the best job we can to make sure that creating the GMO livestock doesn’t create other animal welfare issues, or even issue with productivity.”