Macroscopic and histological characteristics of fluid-filled ovarian structures in dairy cows.

摘要

The primary objective of this study was to use macroscopic and histological features of corpora lutea with a cavity and anovulatory cystic ovarian structures, present in 90 pairs of abattoir-derived dairy cow ovaries, as the basis to clarify the nomenclature of ovarian structures. Excluding morphologically normal ovarian fol-licles (antrum <2 cm, wall <1 mm), there were 27 fluid-filled ovarian structures. Ovulatory structures >16 mm in diameter were designated as Group A (cavity <=10 mm and wall >10 mm) or Group B (cavity >10 mm and wall <10 mm). The volume of luteal tissue was less (P<0.05) in Group B than in Group A, whereas that of a solid corpus luteum (CL) was intermediate (least square means+or-SEM: 72+or-1.92, 11.22+or-1.57 and 5.84+or-1.92 cm3, respectively). There was a greater proportion (P<0.05) of small luteal cells in Group B compared to a solid CL, whereas Group A was intermediate (58.6+or-5.3, 37.4+or-5.3 and 44.0+or-4.4%, respectively). Connective tissue was thicker (P<0.05) in Group B than in Group A (295.4+or-46.9 vs. 153.9+or-38.2 micro m). Based on the above-mentioned characteristics and differences, Groups A and B were designated as a CL with a cavity and a cystic CL, respectively. Furthermore, there were three groups of anovulatory ovarian structures. Structures in Group C were termed persistent/anovulatory follicles (overall diameter and wall thickness <=20 and 1-3 mm, respectively). Finally, Groups D and E were designated as a follicle-fibrous cyst and a follicle-luteinised cyst (based on histological structure) for anovulatory structures with an overall diameter and wall thickness of >=20 and <=3 mm, and >=20 and >=3 mm, respectively.