Determination of Deer Reproductive Parameters on Ossabaw and Sapelo Islands, Georgia

Authors: John W. Bowers, Daniel Forster, and Jim Simmons

In an effort to determine breeding periodicity, ovulation incidence, and parturition frequency for isolated white-tailed deer populations on Ossabaw and Sapelo Islands, ovaries and fetuses were collected from hunter-harvested adult does (>1.5 years of age) taken during a 3-day hunt in December from 1996-2000.  Fetuses were aged immediately after removal using a Forestry Suppliers Fetus Scale for White-tailed Deer based on data by Hamilton et al. (1985). Ovaries for each doe were sectioned and corpora lutea of pregnancy counted following the procedure outlined by Cheatum (1949). Fetal age and corpora lutea of pregnancy data were used to determine breeding periodicity, frequency of fertilization, ovulation incidence, and reproductive rates on the respective islands. A total of 76 and 43 sets of ovaries, and 73 and 41 fetuses were collected from Ossabaw and Sapelo, respectively. Deer on Sapelo Island experienced an earlier average conception and parturition date in all 5 years than did Ossabaw, but the difference was only significant in 2 of those years (1997 and 1998, P < 0.005). Sapelo and Ossabaw experienced a similar frequency of fertilization (0.89 and 0.81, respectively), ovulation incidence (1.21 and 1.26, respectively) and reproductive rates (1.06 and 1.05, respectively). Mitochondrial DNA assays indicate that Ossabaw and Sapelo possess unique genetic populations. Consideration of this genetic uniqueness and its interaction with environmental variables may explain the earlier conception and parturition dates experienced on Sapelo.

Presented at the 26th Annual  Meeting of the Southeast Deer Study Group, February 23-26, 2003, Chattanooga, TN.