Mutations in the leptin receptor gene associated with delayed onset of puberty are also associated with decreased ovulation and lambing rates in prolific Davisdale sheep

The aim of this study was to determine if single nucleotide polymorphisms (SNPs) in the leptin receptor (LEPR) gene associated with delayed onset of puberty are associated with changes in other reproductive traits in adult ewes. The ovulation rate of ewes homozygous for the SNPs was similar to 15% lower (P < 0.001) than either wild-type or heterozygous ewes. First-service conception rate was also affected, being similar to 12% lower (P < 0. 01) in ewes homozygous for the LEPR SNPs than their wild-type or heterozygous contemporaries. Partial failure of multiple ovulations was also increased (P < 0.01) in ewes that ovulated three ova that were either heterozygous or homozygous for the mutations. Ewes homozygous for the mutations in LEPR had on average 0.2 fewer lambs at mid-pregnancy and at birth compared with the wild-type or heterozygous ewes (P < 0.01). Thus, mutations in LEPR were strongly associated with poorer reproductive performance in Davisdale ewes, which is likely to be linked to both a reduced number of ova available for fertilisation and an increased number of ewes failing to become pregnant. Increased partial failure of multiple ovulations in ewes with high ovulation rates (i.e. 3 or greater) may also contribute to the poor reproductive performance.