We measured reproductive parameters of 2,833 female white-tailed deer (Odocoileus virginianus) collected from 1978 to 1986 and 1989 to 1993 in 3 geographical regions of Missouri. Fawn pregnancy and fetal rates were lower (P < 0.001) than those of yearling and older does. Ozark region fawns had lower fetal rates than fawns from the Glaciated Plains region; no other regional differences were found. Fetal sex ratios approached 1:1 and were not influenced by year of collection, litter size, region, or age of doe. However, yearling and older does that conceived late in the annual breeding season produced a higher proportion (P = 0.001) of males than those conceiving earlier. Fawn does breed later in the fall than yearling or adult does, but there were no regional or annual effects on mean conception dates. Most (75%) yearling and adult breeding occurred during a 2-week period while 75% of fawn breeding covered 7 weeks. Our results showed little annual variation in fecundity during a 14-year period for yearling and adult does. Fawn reproductive rates were more variable, suggesting that periodic monitoring of fawn reproduction is warranted.
