The reproductive capacity of the white-tailed deer (Odocoileus virginianus) in Iowa was determined for the period 1957 to 1961. Ovarian structures were checked in 425 pairs of ovaries. Physical characteristics of corpora lutea and corpora albicantia were checked. Breeding by fawns was indicated by the presence of an average of 1.09 corpora lutea per doe in their first winter of life, and by 0.87 corpora albicantia between the ages of 1 and 2 years. This indicates a loss or lack of detection of 25 per cent of the corpora albicantia. As is to be expected, no corpora albicantia were found in fawn does. Adult whitetails had an average of 2.27 corpora lutea per deer, while the mean number of corpora albicantia was 2.21. This indicates a decrease of 3 per cent in counts from corpora lutea to their scar tissue remnants, the corpora albicantia, in deer 2-1/2 years and older. Discussion of technique is included
