Plasma Progesterone and Some Uterine and Embryonic Characteristics in Early Gestation of Colombian Mares

Abstract

Twenty-four Colombian mares from 4 to 14 years of age were inseminated artificially. Progesterone (P4) plasma levels were quantified by the technique of solid phase radioimmunoassay (RIA); corpus luteum (CL), the uterus and uterine edema were evaluated by ultrasonography from ovulation until day 40 post-ovulation. Pregnancy was diagnosed upon detecting a conceptus; it was evaluated daily from that moment until day 40. Data were analyzed using descriptive statistics with mean values and standard deviation (SD). Pregnancy diagnosis was made on day 10.4 ± 0.8 (mean ± SD). The conceptus growth rate was 1.65 ± 0.1 mm / day; attachment to the uterus occurred on day 16.8 ± 1.5. The embryo was visualized within the gallbladder on day 20.8 ± 1.7; its growth rate was 0.8 ± 0.3 mm/day. Heartbeat was detected from day 23.9 ± 1.3. 100 % of the embryos had normal development until day 40 of gestation. 62.5 % of the CL was located in the right ovary and 33.3 % in the left; one animal had double ovulation. 66.6 % of the conceptus was located in the right utero corneal junction and 33.3 % in the left;79.1 % ipsilateral to the CL. Pregnancy in the mare shows physiological characteristics similar to those described in literature. The data presented here are important for clinical evaluations and provide a starting point for future studies.