Two comparable groups of three- to four-year-old Dorper-type ewes were fed a protein-rich supplement in addition to veld grazing to make either small mass gains (6,56%) or substantial mass gains (14,45%) during the gestation period. The quantitative milk production was determined by the lamb-suckling technique and the results indicated that when ewes gained up to 12%mass during the gestation period. There was a corresponding increase in the milk yield. When the mass gained was in excess of 15% there was a marked suppression in the milk yield of ewes.