Association of leptin gene polymorphism with growth, milk production andreproduction traits in Sahiwal and crossbred cattle

Abstract

The genetic polymorphism in exon 2 of bovine leptin gene in purebred Bos indicus (Sahiwal) and crossbred cattle Bos indicus × Bos taurus (Jersey × HF × Sahiwal) was analyzed by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). A 330 bp fragment enclosing the polymorphic HphI site within the second exon was amplified. The digestion of the PCR product with HphI enzyme revealed 2 alleles, viz. allele A (330 bp) and allele V (310 and 20 bp) in crossbred cattle. Only 1 undigested fragment of 330 bp was found in Sahiwal cattle. The results showed a highly significant association of leptin genotypes with the growth traits, first lactation milk yield, second lactation milk yield, average daily milk yield during first lactation and days in milk in first lactation in crossbred cattle. However, nonsignificant association was observed in reproduction traits. The results demonstrated that the heterozygous cows tended to have a better production performance than the homozygous cows.