Association of the porcine alpha-lactalbumin gene to growth, carcass, meatquality and reproductive traits

alpha-Lactalbumin is one of the two major whey proteins in procine milk and may be a regulatory factor in milk yield. Pigs from the University of Illi nois three generation Meishan x Yorkshire reference family (n=259) were gen otyped using a PCR-based test for a polymorphism in the 5' flanking region of the porcine alpha-lactalbumin gene. The PCR product was digested with Rs aI, allowing variation in restriction fragment lengths to be detected by ge l electrophoresis. In the F-2 generation, two alleles (A and B) had a frequ ency of 72.2% and 27.8%, respectively and three genotypes were present at t he frequency of 48.3% AA, 48.0% AB and 3.7% BB. Growth, carcass, meat quali ty and reproductive data were analyzed for associations with alpha-lactalbu min genotype. There was an association between the alpha-lactalbumin genoty pes and age at puberty (P<.05) with heterozygous gilts exhibiting first oes trus approximately 2 wk earlier than pigs homozygous for the A allele and m ore than 4 wk earlier than pigs homozygous for the B allele (AB=142.4 d, SD 9.1; AA=155.5 d, SD 9.0 BB=170.0 d, SD 16.1). Embryo/fetal mortality durin g the 50 d of gestation was also different among the genotypes (AA=29.2%, S D 4.0; AB=23.9%, SD 4.0; BB=6.9%, SD 8.4; P <.05) and there were trends tow ard higher post-weaning (second parity) ovulation rates for AA and AB compa red with BB animals (15.4 ova, SD 1.31; 16.10 ova, SD 1.30; 11.9 ova, SD 2. 01, respectively; P <.10). No significant associations (P >.05) were detect ed between growth and carcass traits and alpha-lactalbumin genotype. There was trend for an association with the intramuscular fat content of the long issimus (AA=3.67%, SD .50; AB=3.87%, SD .50; BB=5.68%, SD .99; P <.10). Thi s study has demonstrated possible associations between the porcine alpha-la ctalbumin gene and some economically important traits that require further investigation.