Relationship between Body Condition Score (BCS) and Reproductive Score (RS) on estrous cycle of Standardbred maiden mares

Standardbred maiden mares are generally in poor physical condition as a result of incorrect feeding management at the end of a racing career. The aim of this study was to investigate the influence of Body Condition Score (BCS: 1–5 scale) and Reproductive Score (RS: 1–5 scale) on ovarian activity of mares during the same breeding season. A total of 29 standardbred maiden mares (7 ± 2 year old) were divided in two groups. Group A (BCS ≥3.0; n = 12) and group B (BCS ≤2.5; n = 17). BCS was determined by visual and palpation inspection before breeding season starting 15 January; day 0. On day 17, RS was determined by gynaecological and ultrasound examination (Aloka SSD 500®, probe 5.0 MHz) of ovaries and uterine horns. On ovulation day (OD) the subjects exited from the study. Regression equations for the prediction of days to first seasonal ovulation (y) were created; the best equation was: y = 1.74BCS3 – 50.72BCS – 28.26RS + 242.16 (R2 = 0.89; SE=11.6 day; p < 0.01). Highly significant relationships were shown in all mares between BCS and RS (0.81; p < 0.01) and between OD and BCS (-0.81; p < 0.01) and RS (-0.92; p < 0.01). In conclusion, combining BCS and RS allows a good prediction of OD in standardbred maiden mares.