Morfometria do placentomo da vaca mestiça Holandês-zebu segundo a ordem de parto

Abstract

This study was conducted to evaluate the morphological characteristics of mestiças cows placentomes with different birth orders. To this end, 15 pregnant Holstein cows, without retained placenta, were used and classified into three groups according to birth order. In the different groups were quantified: number of caruncular epithelial cells, trophoblast binucleated cells population, volumetric proportion of trophoblast binucleated cells and other structural components of the placentome. The volumetric proportion of structural components studied did not differ significantly among the three groups, except in the cases of maternal connective tissue (CM) and fetal epithelium (EF). The volumetric proportion of the CM tissue were in G1 31.36 ± 6.97, G2 19.82 ± 4.06 and in G3 19.38 ± 0.88. A statistically significant difference was observed when comparing G1 with groups 2 and 3 (P <0.05). In volumetric proportion of EF, the mean values of G1, G2 and G3 were 12.52 ± 2.57, 18.46 ± 3.11 and 22.04 ± 4.62, respectively. In this analysis there was a statistical difference between the G1 and G3 (P < 0.05), however the G2 did not differ statistically from G1 and G2 (P > 0.05). The results indicate that there is a decrease in the number of placentome CM in heifers compared to cows of 2° or more births. In the meantime, there was a increase of placentome EF in heifers compared to cows of 3° or more births. Negative, strong and very significant correlations were also observed between the placentome CM in cows, and the EF and their vessels. However, changes in the amount of CM are related to other connective tissue components than collagen, since it showed moderate positive correlations with fetal epithelium.