The butyrophilin (BTN1A1) gene is found at a quantitative trait locus (QTL) in cattle for milk production traits. The effect of a single nucleotide polymorphism (SNP) A465G in exon 8, which causes a lysine to arginine transition, on milk production attributes in Holstein Friesian crossbred cattle from Kerala was investigated in this study (151 numbers). Using custom synthesised primers, a 90-bp fragment encompassing the polymorphic region was amplified from genomic DNA isolated.Genotyping was carried out by high resolution melt curve analysis (HRM) and two genotypes KK (0.25) and KL (0.75) were detected based on melting temperature and melt curve patterns.Sanger’s sequencing and sequence analysis of representative samples confirmed the genotypes.Chi-square test showed that the population was not distributed as per Hardy-Weinberg equilibrium(p≤0.05). The relationship between the A465G transition and milk production traits like 305 daymilk, fat, SNF yields, fat and SNF per cent was determined by general linear model-analysis of variance (GLM-ANOVA). In the model herd, season of calving, parity of animal (non-geneticfactors), and genotype were considered fixed variables and milk production traits as dependent variable. The study revealed significantly higher (p≤0.01) milk fat and SNF per cent for KK genotype(4.14±0.08 %; 7.86±0.06 %) than KL genotype (3.91±0.07 %; 7.73±0.05 %). The butyrophilin genepolymorphism (A465G) can be recommended as a marker for higher milk fat and SNF per cent infuture breeding programmes in crossbred cattle of Kerala.