EFFECTS OF DURATION OF DAILY ILLUMINATION ON REPRODUCTIVE-ORGANS AND FERTILITY OF THE MEADOW VOLE (MICROTUS-PENNSYLVANICUS)

  • 1 January 1979
    • journal article
    • research article
    • Vol. 29  (2) , 182-185
Abstract
The optimum simple, constant photoperiod for voles in a laboratory colony was determined. Voles from an established colony maintained at 22.degree. C with a photoperiod of 14:10 h of light:dark were transferred at 50 days of age to a photoperiod of 12:12, 14:10, 16:8 or 18:6 h of light:dark. From Day 96-102, the 9-10 females per treatment group were paired with a male. Body and gonadal wt, spermatogenesis, ovarian activity and pregnancy were evaluated on Day 110. Reproductive function and body wt of both male and female voles maintained on a photoperiod of 16:8 exceeded (P < 0.05) values for voles exposed to 12:12 h of light:dark and tended to be more favorable than for voles in the 14:10 and 18:6 groups.