Abstract

FREITAS-DE-MELO, Aline et al. Prepartum shearing in ewes and its effects on the energy metabolism and thermoregulation of ewes and lambs. Veterinaria (Montev.) [online]. 2025, vol.61, n.223, e301.  Epub June 01, 2025. ISSN 0376-4362.  https://doi.org/10.29155/vet.61.223.4.

This review synthesizes and discusses information on changes in the energy metabolism of pregnant ewes and their newborn lambs, as well as the modifications induced by prepartum shearing on the metabolism and thermoregulation of pregnant ewes and their lambs. During pregnancy, the availability of glucose in the maternal blood increases and is directed to the placental fetus unit, promoting adequate fetal development, which is maximum during the last third of gestation. A temporary insulin resistance explains the increase in prepartum blood glucose in sheep. After lambing, lambs must preserve their homeostasis by maintaining their blood glucose and body temperature within ranges compatible with life. Neonates rely primarily on glycogen stores and gluconeogenesis to maintain blood glucose and brown fat stores to generate heat. The metabolic status of the ewes during pregnancy directly influences the amount of glycogen and brown fat in the lamb at birth. Prepartum shearing is a management that farmers are increasingly using since lambs are born heavier and have higher survival rates than those born to non-shorn sheep. Prepartum shearing advances insulin resistance before parturition, so the fetoplacental unit begins to capture more glucose earlier. Consequently, muscle and liver glycogen stores and brown fat reserves are greater in newborns born to shorn ewes, which are used as fuels for energy generation and metabolic heat. In summary, prepartum shearing favors the metabolic and morphological characteristics of the lamb that increase the metabolic rate and increase heat production, resulting in fewer deaths due to hypothermia.

Keywords : Pregnancy; Brown adipose tissue; Hypothermia; Carbohydrate metabolism; Sheep.

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