Holm B, Bakken M, Klemetsdal G, Vangen O
Norsvin, NO-2304 Hamar, Norway.
J Anim Sci. 2004 Dec;82(12):3458-64. doi: 10.2527/2004.82123458x.
Genetic correlations between reproduction and production traits were estimated in swine. Reproduction traits investigated were age at first service (AFS), number of live-born piglets in the first litter (NBA1), interval from weaning to first service after first litter (WTS1), number of live-born piglets in the second litter (NBA2), and interval from weaning to first service after the second litter (WTS2). Females generating the data were Norwegian Landrace born in nucleus herds between 1990 and 2000, and the number of records ranged from 13,792 to 56,932. Genetic correlations were estimated among the main production traits in the breeding goal: adjusted age at 100 kg live weight (A100), percentage of lean meat content (LMC), individual feed consumption from 25 to 100 kg (FC), and bacon side quality (BSQ). Average adjusted backfat thickness (BF) was included as a production trait. The A100 and BF traits were recorded on gilts on-farm with 190,454 records, whereas LMC, BSQ, and FC were recorded on-station with the number of records ranging from 12,487 to 12,992. Analyses were carried out with a multivariate animal model using average information restricted maximum likelihood procedures by first running each reproduction trait with A100 and BF, followed by each reproduction trait with LMC, BSQ, and FC. Average heritabilities for reproduction traits were as follows: AFS (0.38), NBA1 (0.11), WTS1 (0.06), NBA2 (0.12), and WTS2 (0.03); and for production traits: A100 (0.30), BF (0.44), FC (0.22), LMC (0.58), and BSQ (0.23). The highest genetic correlation was estimated between A100 and AFS (r(g)= 0.68), also resulting in a positive genetic correlation between FC and AFS. Growth (A100) was negatively (i.e., unfavorably) genetically correlated to NBA1 and NBA2 (r(g) = 0.60 and rg = 0.42 respectively), and so the genetic correlation to FC also became unfavorable (r(g)= 0.23 and r(g) = 0.20). Single-trait selection for enhanced LMC would also affect NBA1 and NBA2 unfavorably (r(g)= -0.12 and r(g)= -0.24). Correlations between BF at 100 kg live weight and reproduction traits were close to zero; however, a low genetic correlation between BF and WTS1 was obtained (r(g)= -0.12), indicating that selection toward reduced BF at 100 kg live weight may have an unfavorable impact on WTS1.
对猪的繁殖性状与生产性状之间的遗传相关性进行了估计。所研究的繁殖性状包括首次配种年龄（AFS）、第一窝活产仔猪数（NBA1）、第一窝断奶至首次配种的间隔时间（WTS1）、第二窝活产仔猪数（NBA2）以及第二窝断奶至首次配种的间隔时间（WTS2）。生成这些数据的母猪为1990年至2000年间出生于核心群的挪威长白猪，记录数量从13,792条到56,932条不等。对育种目标中的主要生产性状进行了遗传相关性估计：100千克活重时的校正年龄（A100）、瘦肉率（LMC）、25至100千克体重期间的个体采食量（FC）以及腌肉质量（BSQ）。平均校正背膘厚度（BF）被纳入生产性状。A100和BF性状是在农场对后备母猪进行记录的，记录数量为190,454条，而LMC、BSQ和FC是在测定站进行记录的，记录数量从12,487条到12,992条不等。采用多变量动物模型，运用平均信息约束最大似然法进行分析，首先将每个繁殖性状与A100和BF进行分析，随后将每个繁殖性状与LMC, BSQ和FC进行分析。繁殖性状的平均遗传力如下：AFS（0.38）、NBA1（0.11）、WTS1（0.06）、NBA2（0.12）和WTS2（0.03）；生产性状的平均遗传力如下：A100（0.30）、BF（0.44）、FC（0.22）、LMC（0.58）和BSQ（0.23）。估计A100与AFS之间的遗传相关性最高（r(g)= 0.68），这也导致FC与AFS之间存在正遗传相关性。生长性状（A100）与NBA1和NBA2存在负遗传相关性（即不利相关性，r(g)分别为0.60和0.42），因此与FC的遗传相关性也变得不利（r(g)= 0.23和r(g) = 0.20）。单性状选择提高LMC也会对NBA1和NBA2产生不利影响（r(g)= -0.12和r(g)= -0.24）。100千克活重时的BF与繁殖性状之间的相关性接近零；然而，获得了BF与WTS1之间较低的遗传相关性（r(g)= -0.12），这表明选择降低100千克活重时的BF可能会对WTS1产生不利影响。
