Investigations of influence of artificial and natural light on developmentof sexual organs and fertility of female rabbits

234 female fattening rabbits with slaughtering on day 84 of age (6 rounds) and 62 does (11 rounds) kept under three light regimes: a) natural light (NL) with an intensity of 27 Lux on average, b) artificial light (AL 8) with 8 hours light a day and c) artificial light (AL 16) with 16 hours light a day (both AL with a mean light intensity of 60 Lux) were included in investigations. Weight of ovaries and uteri was measured a nd percentage of females with follicular development (follicles with diamet er of > 1 mm, Corpora lutea, Corpora haemorrhagica) was verified after slau ghter in fattening rabbits. Data of fertility (rate of conception, litter s ize and litter weight Lit bir th and at weaning) were recorded in does to c alculate on this basis pup index. Weight of ovaries was not influenced by light regime. Female rabbits kept u nder AL 8 had significantly lowest mean weight of uterus and lowest percent age of animals with follicular development (39.7 % compared with 53.1 % in AL 16 and 56.3 % in NL). Against this, highest rate of conception (69.3 %) and highest pup index alive born and weaned pups (593, 547 pups per 100 ins eminated does nsp.) were found in does kept under AL 8. Corresponding value s were 65.9 % rate of conception, 565 alive born and 539 weaned pups/100 do es in AL 16 and 65.7 %. 524, 505 pups resp. in NL.