Genetic variation in the growth hormone (GH) gene influences postnatal growth and placental structure in indigenous Tuj sheep

This study investigated the association between growth hormone (GH) gene polymorphism and postnatal growth and placental traits of Tuj sheep over a 3-year period (2020–2022) at the Atatürk University Sheep Research Farm, Erzurum. The genotype–phenotype association analyses comprised Tuj ewes and their progeny. The polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method using the Hae-III restriction enzyme was applied to identify GH gene variants. Three genotypes were detected: LL (49.0 %), LV (39.0 %), and VV (11.0 %). The mean birth weights were 4.45 kg (LL), 4.52 kg (LV), and 4.36 kg (VV); the weaning weights were 14.80, 15.55, and 14.43 kg, respectively; and the average daily gains were 0.213, 0.226, and 0.209 kg d −1 , respectively. Although the GH genotype had no significant association with birth weight ( p >0.05), it was significantly associated with weaning weight ( p