New Research in Population Health
Nick Boddicker, PhD
In February we attended the World Congress on Genetics Applied to Livestock Production. This conference is held every 4 years and is one of the most informative conferences for livestock geneticists to attend. The conference covers many different topics, including genetics of disease.
Genesus is an active participant in many disease challenge studies, including PRRS, PCV2, and overall disease resilience (currently ongoing). There were many papers on the topic of disease and host genetic control, and there is evidence that the host response to a disease or stressor is partially controlled by the animal’s DNA. Here I would like to share a couple of the unique topic areas.
Infectivity is the ability of a pathogen to spread from animal to animal and make the animal sick, generally in close proximity. This can be viewed as a trait of the pathogen, i.e. can the pathogen survive in the environment, attach to a host, replicate, and spread to a new host. However, infectivity can also be a trait of the host. One presentation by Dr. Andrea Doeschl-Wilson (University of Edinburgh) discussed the hosts ability to infect pen-mates. If there is variation in the animal’s ability to infect pen-mates, some of this variation may be genetic, which means we can select on the trait. Some animals may be high infectors, i.e. pass on more pathogen than other animals. If there is a genetic basis behind this, then selecting for animals that have low infectivity could result in overall reduced impact of the disease on the population, possibly resulting in reduced death loss, better production results during a disease outbreak, and less economic stress on the producer. This area needs more research, but could have a large impact in the area of disease.
Another study from the University of Guelph discussed immune competence measures on boars as an indirect measure of progeny survival. One of the traits measured (cell-mediated immune response) showed boars with higher levels was associated with higher pre-weaning survival of the boar’s progeny. Again, these are early results of a larger project, but the topic is interesting and unique.
Another study by Susanne Hermesch from Animal Genetics and Breeding Unit in Armidale, Australia looked at using the natural stressor of weaning to measure blood parameters to get an idea of immune response and their association with reproduction traits. The study found that Haemoglobin levels (average of 3 littermates) were genetically associated with number of still born piglets in the same litter in which the 3 piglets were measured for Haemoglobion levels. Further research is needed, but in theory of the research results could be implemented at the nucleus, as there are no pathogens being introduced, but the animals do mount an immune response during a normal production process.
Genesus is committed to improving population health through genetics. In addition to participating and investing in disease research, we keep abreast on ongoing research related to disease so that we can achieve our goal of improving population health.
This post was written by Genesus