COMPARATIVE MORPHOLOGICAL STUDY OF OVARIES OF NELORE COWS AND HEIFERS (Bos taurus indicus).

Abstract

In order to verify the morphological changes of the female reproductive tract of Nelore cows, 20 right and left ovaries of 20 3-to-7-years-old cows and 20 heifers aged approximately 2 years were collected in a slaughterhouse. After anatomical measurements and histological analysis were carried out, conclusions were: 1 - The highest measurements and weights were of the ovaries of cows, as well as the right organs for two groups; however, height showed no significant difference between groups, although significant difference was documented between sides; 2 - The frequency of corpora lutea was higher for cows and significantly greater in the right side in the group of cows and heifers; the frequency of mature follicles was higher for heifers, though no significant difference between the sides was observed in both groups; 3 - The ovaries of cows showed a more developed cortical as compared to the medulla, whereas heifers presented the medullar region more extensive than the cortical; 4 - The coating epithelium varied from pavimentous to cubic, and the tunica albuginea and interstitial tissue were typical for cows and heifers; 5 -  Primordial, primary and growing follicles were present in small numbers in cows, whereas a great quantity of the two latter was seen in heifers; 6 – The mature follicles were typical, although vesicular structures near the oocytes were observed in some samples in heifers; 7 - Corpora lutea were typical.

KEY-WORDS: Ovary. Cow. Heifer. Morphology. Nelore.