Updated project metadata. Enhanced nutrition during the early calfhood period has been shown to hasten the onset of puberty in heifer calves. The hypothalamic-pituitary-ovarian biochemical signalling axis regulates reproductive development in heifers, with the dynamics of gonadotropin pulsatility within the anterior pituitary gland, in particular, central to final sexual maturity. However, the precise molecular mechanisms regulating the influence of metabolic status on this signalling axis in heifer calves is yet to be fully elucidated. The objective of this study was to determine the effect of an enhanced plane of nutrition during early life, up to 21 weeks of age, on the anterior pituitary gland proteome of heifer calves. Heifer calves were offered either a high or moderate plane of nutrition. Pathway analysis of differentially abundant proteins highlighted an effect on both growth hormone and GnRH signalling pathways, as well as an effect towards reproductive system development and function