RPL21 and uterine disorder: Genes upregulated in subfertile mares without clinical signs of uterine diseases compared to fertile mares were mainly related to ‘monocarboxylic acid transmembrane transporter activity’ (SLC10A2, SLC16A5, SLC16A9) and protein targeting (RPS17, RPL21, TOMM7, 60S ribosomal protein L26-like pseudogene, 40S ribosomal protein S2 pseudogene).