SONOGRAPHIC CHARACTERISTICS OF ACCESSORY CORPORA LUTEA IN PREGNANT ACYCLIC AND CONVENTIONAL PREGNANT CYCLIC RECIPIENT MARES

Abstract

The finding that hormonally treated acyclic recipient mares can maintain pregnancy through their endogenous production, after the formation of accessory corpora luteum, would reduce the expenses with P4 supplementation in Embryo Transfer programs. The experiment consisted of ultrasonographic evaluations of the ovaries of acyclic recipient mares supplemented with exogenous progesterone (anestrus period) and conventional cyclic mares (breeding season). Pregnancy was found at 15 days of gestation, and the following evaluations were made in the period of formation of the corpora luteum at 30 days of gestation and at gestational follow-up, at 60 and 90 days. The images were recorded and cropped in the region of the corpora lutea and treated in the Pixel Analyser application with the objective of analyzing their dimensions through the pixel color density. The areas of importance were the hyperechoic ones, which represent the parenchyma of these structures, up to 120 days of gestation, estimating whether the P4 production capacity per area in the experimental group would be similar to that of the control group. This would allow us to suppose the possibility of maintaining the pregnancy without exogenous P4 supplementation, which would reduce the costs of hormonal treatment. The statistical analysis consisted of comparing the means between the treatments of the control and experimental groups. Considering that, although at 60 days there is no statistical difference in the size of the hyperechogenic areas, due to the differences between the groups at 90 days of gestation, it would not be advisable to cease hormone supplementation with complete safety, and more information on the subject is needed.