2B-103: Selection for disease resilience - Pilot study: Report prepared for the Co-operative Research Centre for High Integrity Australian Pork

Abstract

Rationale: Disease resilience is the ability of a host to maintain a reasonable level of productivity when challenged by infection (Albers et al. 1987). General immunity depends on innate and adaptive immunity which have are both influenced by genetic factors (e,g. Henryon et al. 2006, Clapperton et al. 2009, Flori et al. 2011). Further, herd health status affected estimates of genetic associations between some immune traits and growth (Clapperton et al. 2009). Therefore, information about the infection load of the environment is required when estimating genetic parameters for survival, health, growth and immune traits that describe aspects of disease resilience. Methodology: Repeated weight measurements were recorded for 2388 pigs from January 2013 to October 2014. A proportion of pigs (910 pigs) had 20 immune traits recorded including differential blood counts, immunoglobulins and haptoglobin. These immune traits were recorded in weaner pigs at 37 days of age. Further information was available about the incidence of disease, medication and mortalities of pigs. A specific scoring methodology was developed for this project to record incidence of disease at each weighing of pigs. Four air quality measures (temperature, humidity, carbon dioxide and ammonia) were collected in individual pens of three pens housing weaner, porker and finisher pigs. Mixed models including fixed and random effects were developed for 15 growth and 20 immune traits.