Acta Vet. Brno 2026, 95: 237-244
Evaluation of corpus luteum vascularization in pregnant mares using colour Doppler ultrasonography
This study aimed to assess changes in corpus luteum (CL) vascularization using Colour Doppler Ultrasonography (CDU) based on pregnancy status and gestational age. A total of 26 Arabian mares were included, comprising 16 pregnant (Group P) and 10 non-pregnant (Group C) mares. The CL images were obtained on post-ovulation days 15, 25, 35, 45, 60, 75, 90, and 120. On day 15, the coloured pixel area (CPA) values of pregnant mares were significantly larger than those of non-pregnant mares (P < 0.001), while no significant differences were found in coloured pixel mean (CPM) and corpus luteum area (CLA) values. The lowest CPA and CLA values were observed on D120 which was significantly lower than at all time points except D90 (for CPA) and D60 (for CLA) (P < 0.05), but CPM values remained stable. A significant decrease in vascularization was detected between early and mid-pregnancy (P < 0.05). In Group P, a negative correlation between age and CPA (ρ = −0.35 to −0.52) was observed, indicating a significant decline in CL vascularization efficiency with advancing age. Time dependent differences in CPA and CLA were significantly related to mares’ age, parity, and foetal sex (P < 0.001). Both CPA and CLA values on D35 were higher in younger (< 10 years) compared to older mares (> 10 years) (P < 0.05). The CLAs on D35 were higher in the 1–3 parities group compared to the 4–6 parities group (P < 0.05), while CPA did not exhibit significant changes related to the parity. These findings suggest that pregnancy status significantly affects CL vascularization patterns. Older mares exhibit reduced vascularization capacity, which may impact reproductive management strategies.
Funding
The authors are grateful to Prof Dr Bülent Ekiz for statistical analysis.
