Genetic parameter estimation and evaluation of Duroc boars for feed efficiency and component traits

Abstract

. 2015. Genetic parameter estimation and evaluation of Duroc boars for feed efficiency and component traits. Can. J. Anim. Sci. 95: 155Á159. The objective of this research was to produce a genetic evaluation for traits related to feed efficiency of Duroc boars. Meeting this objective required partitioning phenotypic (co)variance into additive genetic and environmental components for feed intake and traits indicative of growth and body composition. Boars (N 03291) were housed in group pens of 22 to 24 animals with two electronic feeders per pen and feed intake was recorded for 8 to 14 wk. Body weight was recorded for each boar at the start and end of test, at approximately 100 kg and at up to three times during the test. The pedigree used contained sire and dam of each boar with at least one recorded phenotype (N 04651) and their maternal and paternal grandsires. Variance components were estimated by restricted maximum likelihood for animal models in a series of uni-variate and bi-variate analyses. Two multiple trait genetic evaluations were conducted to predict estimated breeding value for feed intake using animal models. The first evaluation included feed intake (h 2 00.339 0.05), age at 100 kg (h 2 00.3190.04), and subcutaneous fat depth (h 2 00.4790.05). The second genetic evaluation included feed intake, average daily gain (h 2 00.2790.04), mid-test weight (h 2 00.3390.05), and subcutaneous fat depth. Genetic correlations of feed intake with age at 100 kg and fat depth were (0.8090.05 and 0.5790.08, respectively. Estimated breeding values for measures of feed efficiency (residual feed intake and residual gain) were calculated from the results of the second analysis and the associated additive genetic (co)variance components.

The relationship between different measures of feed efficiency and feeding behavior traits in Duroc pigs1

“…Fitting a common litter effect was suggested by Johnson et al (1999), Suzuki (2008), andHoque et al (2009) to further partition the additive genetic variance of G:F and RFI. However, it explained less than 5% of the variation of the traits in our preliminary analysis and, therefore, was removed as suggested by MacNeil and Kemp (2015). The very small proportion of variance accounted for by the common litter effect was expected because the number of observations per common litter was small, approximately 80% of the litters had between 1 and 3 observations each, and therefore, the estimated variance might have been shrunk aggressively toward 0.…”

“…Although RG should be associated with faster growth and independent of feed intake, RIG combines RFI and RG to identify efficient and fast-growing individuals independent of BW (Berry and Crowley, 2012). However, RG and RIG have not been used in swine research (MacNeil and Kemp, 2015). Additionally, relationships between efficiency measures and feeding behavior have not been well documented in the current literature.…”

Genomic evaluation of feed efficiency component traits in Duroc pigs using 80K, 650K and whole-genome sequence variants

“…Data were collected at the Prairie Sun Research and Development Facility (Genesus Inc., Oakville, MB). All animals used in this study were raised under commercial production-like conditions and fed standard diets designed to exceed the pig’s requirements, as described previously [ 29 ]. The proposed work was reviewed by the University of Alberta Animal Care and Use Committee.…”

“…Individual meal events were edited to remove outliers and obvious errors using adapted procedures recommended by Casey et al [ 30 ], as described in [ 29 ]. All boars had to have a minimum of 63 valid feed intake days to pass the edits, along with a minimum of two valid feed intake days per week while on test.…”