The study was carried out to evaluate the effects of supplementary diets with different levels of metabolizable energy (ME) and crude protein (CP) on the performance traits of Rayeni does in the first gestation and their offspring. Animals were fed four supplementary diets during pregnancy and lactation. Supplementary pregnancy diets consisted of two levels of ME (9.20 and 10.12 MJ/kg) and two levels of CP (11.10 and 12.20%) based on dry matter (DM). Dietary treatments during the lactation period contained two levels of ME (10.04 and 11.05 MJ/kg) and two levels of CP (12.70 and 13.96%) based on DM. Kids were weighed from birth to 12 months of age. A patch of fleece was clipped from the left mid-side of each animal (area approx. 100 cm², weight ~18 g). Then fleece samples were tested for cashmere yield, washed fleece yield and mean cashmere fibre diameter. It was shown that the total fleece weight (469 vs 424 g) and final live weight (27.3 vs 25.4 kg) of does fed diet supplemented with higher energy level were improved (P < 0.05). The increase in dietary energy level increased also body weight gain of kids, greasy cashmere fleece weight (457 vs 419 g) and clean cashmere weight (327 vs 297 g) of kids. So, it can be concluded that supplementary feed with an increased level of energy, but not protein, for grazing does, in the critical period of the last month of pregnancy and birth time, is necessary to optimize the performance of the Rayeni cashmere goats and their offspring.