Histology confirms that macroscopic evaluation of ovaries is a valid method for the assessment of the reproductive status in wild boar

摘要

Research on reproduction and fertility is an essential fundament of management strategies in European wild boar. Concerning the examination of the reproductive tract, methods still lack conformity and comparability. So far the reproductive status of female wild boar has been assessed by ovarian macroscopic examination. In order to find out if this is a valid method, 21 ovaries of 8-34 months old animals covering (early) follicular phase and cyclic inactivity were evaluated microscopically. Number and dimension of follicles as well as the occurrence of atretic follicles were compared and related to age, weight, ovary weight and size of ovary. For this study, 21 ovaries of the right side of each animal were weighed and measured. The diameter of the functional bodies was measured and functional bodies were counted. Size of ovary was calculated by length*width*height (cm(3)). Macroscopically, follicles were classified into four categories by diameter: F1 (0.2-0.3 cm), F2 (0.4-0.5 cm), F3 (0.6-0.8 cm) and F4 (0.9-13 cm). Microscopically, antral follicles of every 10th slice per section of each ovary were counted and classified into three categories by diameter: F0 (&= 2 mm), FS (1-2 mm) and FXS (&= 1 mm). In follicles with a diameter greater than 2 mm (F0), length and width were measured from the beginning of theca interna. Results showed that age and weight of wild boars were highly correlated (cor = 0.845, p & 0.001). Wild boar of higher age and weight showed higher ovary weight, but this was not significant (p = 0.135 (age), p = 0329 (weight)). Although the number of macroscopically seen follicles differed widely by animal, microscopically only one ovary showed only small tertiary follicles. Animals with bigger follicles showed a significantly (p = 0.006) smaller number of small and smallest tertiary follicles. The number of tertiary follicles (F0) was not significantly influenced by age or carcass weight (p = 0.460, 0.159). Older and heavier animals showed significantly less FX and FXS (p & 0.001). Comparison of the follicular composition of young wild boar ovaries with domestic pig research allows the conclusion that assessment of cyclic activity and near puberty is possible. However, due to the fact that puberty is a long term biological progress, defining the time of sexual maturity will always be an estimate. Nevertheless, microscopic examination confirmed the macroscopic findings, including follicular dimensions and developmental stage allowing the conclusion that macroscopic evaluation of ovarian functional bodies in wild boar is an easy and reliable way to assess reproductive performance. (C) 2018 Elsevier Inc. All rights reserved.