The largest losses in lambs occur around birth. When ewes are underfed or overfed during the last part of gestation, the risk of underweight or overweight lambs increases. There are disadvantages to both situations: lightweight or weak lambs often don’t consume sufficient amounts of colostrum, and consequently may die of a variety of causes, like starvation and hypothermia. Overweight lambs, on the other hand, may experience a problematic birth process.