Estimation of Genetic Parameters and Trends for Length of Productive Life and Lifetime Production Traits in a Commercial Landrace and Yorkshire Swine Population in Northern Thailand

The objective of this research was to estimate genetic parameters and trends for length of productive life (LPL), lifetime number of piglets born alive (LBA), lifetime number of piglets weaned (LPW), lifetime litter birth weight (LBW), and lifetime litter weaning weight (LWW) in a commercial swine farm in Northern Thailand. Data were gathered during a 24-year period from July 1989 to August 2013. A total of 3,109 phenotypic records from 2,271 Landrace (L) and 838 Yorkshire sows (Y) were analyzed. Variance and covariance components, heritabilities and correlations were estimated using an Average Information Restricted Maximum Likelihood (AIREML) procedure. The 5-trait animal model contained the fixed effects of first farrowing year-season, breed group, and age at first farrowing. Random effects were sow and residual. Estimates of heritabilities were medium for all five traits (0.17 +/- 0.04 for LPL and LBA to 0.20 +/- 0.04 for LPW). Genetic correlations among these traits were high, positive, and favorable (p<0.05), ranging from 0.93 +/- 0.02 (LPL-LWW) to 0.99 +/- 0.02 (LPL-LPW). Sow genetic trends were non-significant for LPL and all lifetime production traits. Sire genetic trends were negative and significant for LPL (-2.54 +/- 0.65 d/yr; p = 0.0007), LBA (-0.12 +/- 0.04 piglets/yr; p = 0.0073), LPW (-0.14 +/- 0.04 piglets/yr; p = 0.0037), LBW (-0.13 +/- 0.06 kg/yr; p = 0.0487), and LWW (-0.69 +/- 0.31 kg/yr; p = 0.0365). Dam genetic trends were positive, small and significant for all traits (1.04 +/- 0.42 d/yr for LPL, p = 0.0217; 0.16 +/- 0.03 piglets/yr for LBA, p<0.0001; 0.12 +/- 0.03 piglets/yr for LPW, p = 0.0002; 0.29 +/- 0.04 kg/yr for LBW, p<0.0001 and 1.23 +/- 0.19 kg/yr for LWW, p<0.0001). Thus, the selection program in this commercial herd managed to improve both LPL and lifetime productive traits in sires and dams. It was ineffective to improve LPL and lifetime productive traits in sows.