Effects of light intensity on reproductive performance of mice

The effect of light intensity on reproduction in mice has not been investigated extensively. It was the purpose of this study to determine the effects of 10, 50, and 90 foot candles (ft.-c.) of light on the reproductive performance of C₃H/HeJ mice housed in either transparent or translucent cages. Filter covers on the cages minimized the influence of disease on the colony. Daylength was 14 hours for all treatments. The incidence of sterile matings was significantly higher(P < .01) within the 90 ft.-c. group. Neither light intensity nor cage type significantly affected (1) the age of dam at first parity, (2) the number of mice born or weaned, or (3) the Q factor (number of mice produced per 100 breeding days). Considering the results of the present study, the following conclusions are made subject to the conditions of this experiment: 1. Suddenly increasing light intensity by 50 to 100 percent at puberty may cause sterility in some new matings. 2. Fertile mice maintained at illumination levels of 10, 50,or 90 ft.-c. will have similar levels of reproduction. 3. Mice reproduce equally well in transparent or translucent cages.