Genotype of melatonin receptor MT1 (MTNR1A) and puberty in Mediterranean Italian buffalo

Summary In adult buff aloes, polymorphism of the MT1 receptor gene has shown to infl uence the reproductive seasonality. Th e aim of study was to assess whether the polymorphism of the MTNR1A gene may infl uence puberty in Mediterranean Italian buffalo. Th e study was conducted using 50 prepubertal buff alo cows that at the age of 15 months were placed into the group where there was the male. Estrus detection was performed by observing estrous-behaviour and pregnancy checking by palpation per rectum and/or ultrasound between days 40 and 60 post-mating. Also of each animal dates of calving was recorded. From each buff alos a blood sample was collected and used for DNA extraction. PCR analysis was performed using 100-150 ng of DNA to amplify the second exon of the MTNRA1 gene. All PCR products were digested with 2U of enzyme HpaI to highlight the polymorphism at position 82 (characterized by a C to a T substitution) of the MTNR1A gene. Frequency of C and T alleles was respectively 0.42 and 0.58 in the analyzed population which resulted in Hardy Weinberg equilibrium. Th e genotypic frequency was 28% for genotype C/C, 38% for C/T and 34% for T/T. Th e registration of reproductive data showed that the fi rst heat is around the age of 20 months and the fi rst calving around 32 months. Our data show that the genotype of the MTNR1A does not infl uence the onset of reproductive activity in prepubertal buff alo cows.