Estimation of Genetic Parameters in Berkshire Population Reared in a Hoop Structure

The objective of this study is to estimate genetic parameters in Berkshire population reared in a hoop structure at the university farm of North Carolina Agricultural and Technical State University (NC A&T SU). The swine unit at NC A&T SU has a 15m x 30m hoop facility that is different from standard confinement facilities. The deep bedding, generally straw, corn stalks, or hay, is spread approximately 34-45 cm thick and provides a comfortable environment for the animals which allows rooting and other natural behaviors. The Berkshire population has been being constructed since 2011 for the selection experiment. Pigs were farrowed outdoor in farrowing huts, weaned at 4 weeks of age, and reared within deep-bedded hoop houses after that. The number of pigs in the pedigree was 161. Average daily gain (ADG) and backfat thickness (BF) were collected from 43 pigs at 20 weeks of age. There were 22 intact male and 21 female pigs, and two contemporary groups (birth year-month). Contemporary group and sex were included in the model as fixed effects, and the animal effect was included as a random effect. The animal model was analyzed with MTDFREML. The means of ADG and BF were 0.28±0.06kg and 7.68±1.25mm. The coefficients of variation were 20.18 and 16.34, and the estimated heritabilities were 0.26±0.01 and 0.35±0.01 in ADG and BF, respectively. Average daily gain and the heritability were lower than the results reported in the past, which may be due to rearing outdoor.