The genetic diversity of livestock and poultry is dwindling, leaving one-third of the world’s protein supply at risk to events such as weather extremes and disease outbreaks. A new paper from the Council for Agricultural Science & Technology (CAST) addresses the risks associated with reduced access to genetic traits as well as what should be done to protect remaining breeds. According to the paper, “up to 25% of global livestock breeds are either at risk of being lost or have already been lost.”
The U.S. has one of the most vibrant livestock sectors in the world. Livestock breeders produce the genetic resources necessary to address domestic consumption and supply genetic resources globally. The productivity of the U.S. livestock sector, however, is based upon ready access to and use of highly specialized genetic resources, and there is cause for concern at multiple levels, the report warns.
When moving beyond the handful of productive breeds, the reports notes that up to 20% of livestock and 79% of poultry breeds are classified as “at risk” for extinction (according to the U.N. Food & Agriculture Organization, 2007). “Although the rare livestock and poultry breeds are currently not major contributors to modern U.S. agriculture, one can examine the recent outbreaks of highly pathogenic avian influenza in the United States (or outbreak of African swine fever in China) and realize that over-reliance on a few highly productive breeds could endanger the global food supply if these productive breeds are highly susceptible to a new pathogen,” the report adds.
The authors warned that the livestock industry cannot continue to rely solely on a few breeds to provide the genetic diversity that is integral to sustaining food production for future generations, as researchers cannot predict what traits will become important in the face of weather extremes, niche markets and consumer-driven demands. Disappearance of breeds is likely to induce losses of entire genetic combinations, and it is these combinations that stand to serve as ready-made matches for breeders to use, the report adds.
“Conserving breeds saves these options and keeping them in the agricultural landscape is a reminder that these options exist. The most effective conservation of these resources ideally involves living animals as well as cryopreserved reservoirs of their genetic material. On-farm conservation and cryopreservation of animal germplasm are complementary strategies for conservation of genetic diversity in livestock and poultry,” the report recommends.
Current conservation practices such as cryopreservation and germplasm repositories are already in use to protect the genes of some animal livestock breeds, but the authors of the CAST paper argued that more must be done to prepare for unpredictable future events. They included five recommendations that build on current conservation practices.
“By losing breeds, we make finding potential solutions to future production demands much more difficult, and recent history indicates that predicting future demand is problematic,” the authors wrote. “Conserving breeds saves these options, and keeping them in the agricultural landscape is a reminder that these options exist.”
Living populations are advantageous because they can adapt to changes in the natural or production environment. Genetic material from livestock and poultry can be cryopreserved in several forms: male gametes (spermatozoa), female gametes (oocytes), embryos, embryonic cells, gonadal tissue, primordial germ cells (PGC) and somatic tissues. The bovine is the only farm animal species for which cryopreservation of sperm is commercially routine. The success of semen cryopreservation in sheep and goats is lower than that of cattle but better than swine. Among the major mammalian food animal species, the pig poses the greatest challenge for semen cryopreservation, according to CAST.
Gene banks have been established across the globe to protect livestock and poultry industries from loss of genetic diversity that could subsequently hinder their capacity to adapt to new environmental or market pressures.
Each strategy mitigates a different array of specific risks to agrobiodiversity, and one strategy should not proceed at the expense of another; concurrent efforts are needed. “An increased scope of intensified sampling, cataloging and evaluation of the existing gene pools in livestock and poultry, concomitant with more resources to fully develop cryopreservation methodologies and discover novel, more efficient methodologies, are paramount to meet the expected increases in human population in the face of unknown — but certain — global challenges,” the report states.
The CAST authors recommended committing the resources – capital, personnel, facility and information technology – necessary to characterize the genetic diversity of existing livestock and poultry populations. In addition, they suggest engaging in private sector philanthropic awareness and expanding funding opportunities across the federal government for research to develop the most effective cryopreservation strategies for domesticated livestock and poultry species.
The report suggests supporting the conservation of in situ populations, particularly for those species such as poultry in which cryopreservation methods are suboptimal, through funding opportunities related to maintaining important genetic stocks for research, small farms, urban development and/or sustainable agricultural practices. Additional recommendations include a call to evaluate cryopreserved germplasm whenever possible for the potential to generate offspring (not just fertility) and use data to inform the minimum collection score to provide the best protection of genetic resources for future use.
The final recommendation includes expanded investment in permanent staffing and programmatic support of the U.S. Department of Agriculture's Agricultural Research Service established the National Animal Germplasm Repository (NAGR) to increase the procurement, management and utilization of genetic resources. “More staff are needed with technical expertise in the areas of cryopreservation, genetics, assisted reproductive technology and information technology; additional funding also should be provided to the NAGR and universities to support census and outreach activities as well as evaluation of cryopreserved materials,” the report states.