Ovarian features in white-tailed deer (Odocoileus virginianus) fawns and does.

G D A Gastal,G A Apgar,S G S De Tarso,A Hamilton,J M Feugang,E L Gastal,C K Nielsen,B G Alves,W J Banz,Carlos E Ambrósio

doi:10.1371/journal.pone.0177357

Abstract

The knowledge about ovarian reserve is essential to determine the reproductive potential and to improve the methods of fertility control for overpopulated species, such as white-tailed deer (Odocoileus virginianus). The goal of this study was to evaluate the effect of age on the female reproductive tract of white-tailed deer, focusing on ovarian features. Genital tracts from 8 prepubertal and 10 pubertal females were used to characterize the preantral follicle population and density, morphology, distribution of follicular classes; stromal cell density; and apoptosis in the ovary. In addition, uterus and ovary weights and dimensions were recorded; and the number and the size of antral follicles and corpus luteum in the ovary were quantified. Overall, fawns had a greater (P < 0.05) preantral follicle population, percentage of normal follicles, and preantral follicle density than does. The mean stromal cell density in ovaries of fawns and does differed among animals but not between age groups. The apoptotic signaling did not differ (P > 0.05) between the ovaries of fawns and does. However, apoptotic ovarian cells negatively (P < 0.001) affected the preantral follicle morphology and density, and conversely, a positive correlation was observed with stromal cell density. As expected, the uteri and ovaries were larger (P < 0.002) and heavier (P < 0.001) in does than in fawns. In conclusion, this study has shown, for the first time, the preantral follicle population and distribution of classes, rate of morphologically normal follicles, and density of preantral follicles and stromal cells in white- tailed deer. Therefore, the findings herein described lead to a better understanding of the white-tailed deer ovarian biology, facilitating the development of new methods of fertility control.

Highlights

In North America, white-tailed deer (Odocoileus virginianus) are one of the most predominant herbivore species of wildlife
The goal of this study was to evaluate the effect of age on the female reproductive tract features of white-tailed deer fawns and does to: (i) characterize preantral follicle population and density, morphology, and distribution of follicular classes in the ovary; (ii) quantify density of ovarian stromal cells; (iii) evaluate apoptosis in the ovary; (iv) describe macroscopic dimensions and weight of uteri and ovaries; and (v) quantify macroscopic antral follicles, and corpora lutea and albicans
The present study describes, for the first time, the preantral follicle reserve including preantral follicle population, density, morphology, and distribution of classes in the ovary of white-tailed deer within two different age groups

Summary

Introduction

In North America, white-tailed deer (Odocoileus virginianus) are one of the most predominant herbivore species of wildlife. More than any other wildlife species, white-tailed deer have caused a variety of damages, such as: crop loss, automobile and aviation. Hunting is facilitating as a method of controlling the deer population, lethal methods are not adequate for effective management in several regions, such as in areas of prohibit hunting, for example in urban areas, national parks and other types of conservation reserves [4]. Wildlife scientists and professionals are developing various non-lethal methods of population control including contraceptive treatments [5,6,7,8]. Because of the lack of information on ovarian function of white-tailed deer, more studies are needed to understand the reproductive physiological events to improve the efficiency of contraception and fertility methods

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Results

Conclusion