The effect of plane of nutrition on metabolism has been an important topic of discussion in ruminants from late pregnancy to early lactation. Lactation represents a unique state of homeorhesis, where metabolism is coordinated to support the mammary gland's energy demands for milk production. The intricate physiological adaptations that lactating ruminants undergo involves the development of insulin resistance. Insulin resistance emerges as a pivotal mechanism that ensures glucose partitioning toward the mammary gland, a process facilitated by insulin-independent glucose transporters. While much is known about these mechanisms in nonruminants and early lactation cows, this study shifts the focus to ewes during the transition from late gestation to early lactation. This critical period is marked by significant physiological changes, yet the precise factors triggering insulin resistance and the influence of plane of nutrition remain elusive. To address these gaps, the research aims to elucidate the relationship between plane of nutrition and changes in glucose tolerance in late gestation and early lactation ewes. By unraveling these intricate interactions, the study contributes to a deeper understanding of the physiological adaptations that underlie successful lactation in ruminants.