<![CDATA[ABSTRAK Gen Pituitary Specific Transcription Factor 1 (PIT1) adalah gen yang mengatur kelenjar pituitari dan merupakan regulatory factor hormon pertumbuhan serta hormon lain yang terkait dengan produksi susu. Oleh karena itu, penelitian ini bertujuan untuk mengasosiasikan variasi genotipe PIT1 dengan produksi susu sapi Friesian Holstein (FH) di Indonesia. Sebanyak 42 ekor sapi dipilih sebagai sumber DNA. Variasi genotipe ditentukan dengan metode Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) menggunakan enzim restriksi HinfI. Data produksi susu diambil pada laktasi 1 dan 2 yang distandardisasi ke catatan produksi 305 hari. Sebanyak 3 variasi genotipe terdeteksi yaitu AA, AB, dan BB dengan frekuensi masing-masing 0,21; 0,26; dan 0,52. Pada penelitian ini diperoleh frekuensi alel A sebesar 0,35 dan B sebesar 0,65, dan populasi berada pada kondisi setimbang (p<0,05). Genotipe BB pada penelitian ini memproduksi susu lebih tinggi (p>0,05) dibanding AA dan AB pada laktasi 1, namun pada laktasi 2 antar genotipe tidak berbeda nyata. Berdasarkan hasil penelitian maka disimpulkan bahwa variasi genotipe gen PIT1 memiliki potensi untuk digunakan sebagai penanda genetik kemampuan produksi susu sapi FH di Indonesia.Kata Kunci: asosiasi, produksi susu, sapi FH Indonesia, variasi genotip gen PIT1.Association of PIT1|HinfI Genotype Variation on Milk Production of Indonesian Friesian Holstein Dairy Cattle ABSTRACT Pituitary Specific Transcription Factor 1 or known as PIT1, is a gene which function to control the pituitary gland and act as regulatory factor for growth hormone and other hormones related to milk production. The current study was aimed to associate the variant of PIT1 genotype on milk production in Indonesian Friesian Holstein. In total, 42 dairy cows were sampled for DNA source. Phenotypic data of milk yielded from first and second lactation were recorded then standardized to 305 days. To scan PIT1 genotype variation, PCR-RFLP was employed using HinfI restriction enzyme. Three types of PIT1 genotype were found, namely AA, AB, and BB; its frequencies were 0.21; 0.26; and 0.52, respectively. The allele frequencies of allele A and B were 0.35 and 0.65, and the population is in equilibrium condition (p<0.05). Significant associations (p<0.05) were found between genotypes in lactation 1. In this study, BB genotype yielded highest milk compared to other genotypes in lactation 1, but no differences among genotypes were observed in lactation 2. In a conclusion, the variation of PIT1 genotype in Indonesian Friesian Holstein shows potential use for genetic marker to improve milk production in this study.Keywords: association, milk yield, Indonesian Friesian Holstein, PIT1 genotype variation]]>
