Morphological analysis, cytological, and oocyte quality of reproductive tract of bovine females submitted to slaughter

The disorders that cause infertility and subfertility in cows can be either infectious or not, or originate from errors in breeding and nutrition. Uterine infections are among the main causes of infertility, negatively influencing ovarian activity and reproductive performance of animals. Thus, the purpose of this study was to characterize the main reproductive disorders through macroscopic and cytologic evaluations of the uterus of cows, focusing on the disorders that cause a decrease in reproductive efficiency, and to correlate the different degrees of uterine infection with oocyte quality. This research was approved by the Ethics Committee on Animal Use (CEUA) of the Federal University of Espirito Santo, under number 76/2015. 98 reproductive tracts were obtained from slaughterhouses. In relation to macroscopic aspects, changes related to morphology, consistency and color were evaluated. Inflammation was classified according to the aspect of the uterine secretion as: modera clinical infection (grade II): presence of cloudy or catarrhal mucus; severe clinical infection (grade III): presence of purulent mucus (Ferreira et al, Brazilian Agricultural Research 22: 339-344, 1987). The diagnosis of subclinical uterine infection (grade I) was conducted by endometrial cytology obtained by endometrial scraping. Subclinical infection was characterized by the presence of more than 3% neutrophils, from the 200 cells counted (Salasel et al, Theriogenology, 74: 271-1278, 2010). The oocyte quality of each ovary/animal was analyzed according to the number of cumulus cell layers and cytoplasm aspect, and was classified as: grade I: excellent quality, grade II: intermediate, and grade III: poor. The data was analyzed using Descriptive Statistical Analysis, Spearman Correlation test, and Post-compared with Studentu0027s t test, with 5% significance level. In regards to ovarian changes, 1.02% of ovarian cysts, ovarian agenesis and ooforites were observed. 4.08% of the animals had uterine wall thickening. 1.02% of the animals had an increase in length of the uterine horns, uterine fibrosis, and the presence of clots. There were 12.24% of uterine clinical infections cases. 6.12% of the animals with positive endometrial cytology were diagnosed with subclinical uterine infection. In the analysis using the Spearman Correlation test, there was a negative correlation (r = -0.14), with no significance between uterine infection and rates of recovered oocytes grade I and II.Clinical and subclinical uterine infections were the most frequent changes are possible causes of decreased fertility. There wasnu0027t significant correlation between the degree of uterine infection and oocyte quality of animals.