This study investigated the effects of supplementary feeding at different physiological stages in a crossbreeding programme on the reproductive performance of goats, and the growth and performance of their offspring (purebred, F1, F2 and B1). Hair, Saanen × Hair F1 (SHF1) and Alpine × Hair F1 (AHF1) crossbred goats were studied in four pasture-based flocks considering the effects of the lunar cycle, parturition time and some environmental factors. Crossbreeding both increased the twinning rate and shortened the gestation period (P<0.05). The distribution of births over the day was mostly between 06:01 and 09:00 (P<0.05; 38.4%). The distribution of births in eight different moon phases showed statistical differences (P<0.05). The lowest number of births (7.6%) occurred during the new moon phase and the highest number of births (20.9%) during the last quarter moon phase (P<0.05). In addition, a much higher birth rate in goats was observed on nights with a bright moon phase than on nights with a dark moon phase (P<0.05). Environmental factors had a significant effect on gestation age at birth and on time from birth to yearling weight of purebred, F1, F2, and B1 generation crossbred kids (P<0.01 to P<0.05). The estimated Kleiber ratio of genotypes was important for weight gain from birth to 12 months of age (P<0.05). This study shows that innovative sustainable goat production systems can be developed through better modelling of environmental changes in mountain areas, and that the reproductive and growth traits of local goats can be improved through crossbreeding.