Polymorphism of the Prolactin Gene and Its Relationship with Milk Production in Gir and Kankrej Cattle

BACKGROUND The aim of this study was to detect allelic and genotypic frequencies of prolactin (PRL) gene in Gir (200) and Kankrej (100) cattle and to analyze milk production traits of tested cattle on their PRL genotypes. MATERIALS AND METHODS The 156 bp fragment located in exon 3 was amplified using polymerase chain reaction-restriction fragments length polymorphism technique. RESULTS Allele frequencies in the studied breed were A = 0.52 and B = 0.48. Means and standard deviations for milk yield and fat content (%) were 3811.6 ± 462.1 and 3.99 ± 0.18 for the AA genotype, 3514.9 ± 450.8 and 4.16 ± 0.33 for the AB genotype, and 3388.8 ± 423.3 and 4.34 ± 0.11 for the BB genotype, respectively, in Gir cattle. Similarly, for Kankrej cattle, means and standard deviations for milk yield and fat content (%) were 2007.8 ± 246.3 and 4.05 ± 0.16 for the AA genotype, 1846.14 ± 133.4 and 4.10 ± 0.156 for the AB genotype, and 1767.7 ± 186.4 and 4.30 ± 0.178 for the BB genotype, respectively, in Kankrej cattle. CONCLUSION This study showed differences in milk traits among PRL genotypes of Gir and Kankrej cattle.