Genetic and phenotypic relationships between performance test and reproduction traits in Large White pigs

Abstract

Genetic and phenotypic relationships between performance test and reproduction traits were estimated, after five generations of divergent selection for components of efficient lean growth, in a population of Large Wltite pigs. On ad-libitum feeding, a total of 4334 pigs were performance tested, of which 884 selected gilts had measurements of reproduction traits. On a restricted feeding regime, 1558 pigs were tested, which included 336 selected gilts with reproduction records. For pigs given food ad libitum, genetic correlations between litter weights at birth and weaning with daily food intake (0·48 and 0·42, s.e. 0·16) and with growth rate on test (0·65 and 0·52) were positive, but correlations with backfat depths were not significantly different from zero. For pigs given food at a restricted level, litter birth weight was positively genetically correlated with growth rate (0·50, s.e. 0·18) and negatively correlated with backfat depths (-0·48, s.e. 0·16). Phenotypic and environmental correlations between performance test and reproduction traits were all less than 0·10 in magnitude, for pigs tested on either feeding regime. The variation in backfat depth enabled detection of a non-linear relationship between predicted breeding values for litter weight at birth with predicted breeding values for average backfat depth of farrowing gilts performance tested on ad-libitum feeding, but not for gilts tested on restricted feeding. The positive genetic correlations between growth rate and daily food intake with litter traits suggested that selection strategies which change growth and daily food intake may result in relatively greater genetic changes in piglet growth rate than in litter size.

Correlations between fattening and slaughter performance test results of gilts and their subsequent reproductive performance

“…Bereskin (1984), Ferguson et al (1985), Cleveland et al (1988) and Kerr and Cameron (1996) reported negative genetic correlations of fattening and slaughter traits with reproductive traits. The correlations between weight gain and number of piglets per litter on day 21 were estimated by Bereskin (1984) to be r = -0.60.…”

Relationships between quantitative and reproductive fitness traits in animals

“…Correlated responses in LS traits in a landrace line selected for 200 day weight, however, produced relationships that were small, and regression coefficients for reproductive traits that did not differ significantly from zero (Kuhlers & Jungst 1993). Kerr & Cameron (1996) estimated genetic and phenotypic relationships between performance test and reproduction traits, after five generations of divergent selection for daily food intake, lean food conversion and lean growth rate in 865 ad-libitum fed large white pigs. They concluded that selection directed to increase lean growth rate and/or reduce daily food intake may have a negative effect on reproductive performance, even though estimates of the genotypic and environmental correlations between traits were small.…”

Genetic variation and responses in reproductive performance of sows in lines selected for growth rate under restricted feeding

“…Genetic correlations of piglet or litter weights at birth or weaning have been found to be consistently positive with daily gain and negative (i.e. favourable) with backfat by Tholen et al (1996), Cameron (1996a), andHermesch et al (2000). However, correlated responses in litter birth (or weaning) weights to selection for high lean growth in other studies have been either negative (DeNise et al, 1983;Fredeen and Mikami 1986) or non-significant (Cleveland et al, 1988;Chen et al, 2001;Gibson et al, 2001).…”