Sheep in extensive grazing systems often face periods of poor-quality forage, particularly during winter, which can impede ewe nutrition during pregnancy. Nutrient restriction during mid-to-late gestation is known to negatively impact ewe health and lamb development. This study investigated early life performance in lambs from ewes fed a poor-quality diet that simulates winter forage with a prolonged moderate nutrient restriction followed by late gestation supplementation, versus lambs from ewes fed a diet meeting all nutritional requirements for the entirety of gestation. Ewes receiving the poor-quality diet lost weight and body condition during the feeding period well before traditional supplementation windows. Lambs from poor-quality diet ewes were born at similar size to controls but were more likely to experience hypothermia in the first week of life, despite having normal blood glucose concentrations. From 5 wk of age until weaning, lambs from poor-quality fed ewes grew slower and asymmetrically. These results indicate that even moderate nutritional challenges during pregnancy can impair lamb thermoregulation and growth, highlighting the importance of maintaining ewe nutrition at all gestational time points to support offspring health and productivity.

Read the full article in the Journal of Animal Science.