Prolactin gene polymorphism in crossbred cattle of Assam and its association with productive and reproductive traits

Abstract

The present investigation was designed to study the performance of crossbred cows as well as to identify polymorphism in genomic sequences of PRL gene and its association with various reproductive and productive traits of crossbred cows maintained at the Bull Mother Farm, Barapeta, Assam. A total of 40 cows were utilized to study the polymorphism of the PRL gene, the results of which showed polymorphic banding pattern in most of the samples of crossbred cows with respect to the gene under study. Polymerase Chain Reaction-Restriction Fragment Length Polymorphism studies on PRL gene in crossbred cows, using Rsa I restriction enzyme revealed three types of fragment pattern, arbitrarily designated as AA (156 bp), AB (74, 82 and 156 bp), BB (74 and 82 bp) genotype. The frequencies of A and B alleles were calculated as 0.534 and 0.466 and those of AA, AB and BB genotypes as 0.334, 0.400 and 0.266 respectively. The prolactin genotypes were found to be significantly related to age at sexual maturity, age at first calving, first lactation milk yield. The crossbred cattle with AB genotype showed better performance than those with AA and BB genotype in the population studied.