Disease is a major threat to pig production worldwide. Disease breaks impact profitability, disrupt pig flows, and compromise animal welfare. Many different factors contribute to the spread of disease, such as rearing animals in high-hog dense areas, gaps in biosecurity, and pathogen mutation. For this reason, disease control is considered a multifactorial issue which, therefore, requires a combination of different types of solutions. One such solution is breeding pigs for enhanced, natural resilience to disease.
Disease resilience is defined as an animal’s ability to maintain performance in the face of a disease challenge, or to recover quickly following exposure. According to this definition, disease resilience is not specific to a certain pathogen, but refers to animals that are simply better at responding to disease in general, whether caused by a viral pathogen, bacterial pathogen, or other disease-causing agent. There is substantial evidence from the literature, and from our own research trials, that this type of general resilience to disease is heritable. This means that it’s possible to identify animals with superior genetic merit for disease resilience which, when mated, produce offspring that are naturally more resilient to disease. Disease resilience, like most health and welfare traits, is controlled by many different genes. Therefore, the only way to take advantage of the combined effect of these genes is by using genetic selection.
In 2018, Topigs Norsvin began developing a strategy to breed pigs for enhanced, natural disease resilience. This strategy requires collecting data in real-world challenge scenarios, including exposure to major swine diseases. Data collected in this way captures variation in how pigs respond to disease, and are used to derive an individual’s genetic merit (i.e. breeding value) for disease resilience. This is the same process used to estimate genetic merit for other traits, like growth, feed conversion, and litter size.
In a recent “proof of concept” study, breeding values for disease resilience were estimated for TN Duroc boars at a single stud in the USA. These breeding values were estimated using thousands of genotypic and phenotypic records collected under diseased challenged conditions. Boars were then ranked based on their breeding value for disease resilience and the top 30 (aka “High Resilience”) and bottom 30 (aka “Low Resilience”) boars were selected to be used as sires. Topigs Norsvin TN70 females were inseminated with semen collected from either High or Low Resilient boars to produce pigs in the High vs. Low Resilience progeny group, respectively.