Periconceptional body condition, feto-placental development and foal metabolism in horses

Abstract

International audience32 pregnant saddlebred mares were divided in 2 groups from 7 months of gestation. Control mares (n=15) were fed to requirements whereas H-mares (n=17) were fed +15.5% energy and +30.4% proteins. Maternal weight and body condition score (BCS, 1-5 scale), foal growth and fasting glycemia were monitored. Results were analyzed using a linear model.The BCS of H-mares remained ≥3.5 throughout gestation but that of L-mares decreased from 9 months of gestation (foaling BCS: 2.75) despite no difference in weight. Fasting glycemia in H-foals was lower at 1 month (p=0.03) and 3 months (p=0.09, tendency) compared to controls. There was no other difference between groups. Data were analyzed sorting the mares according to BCS at insemination into Fat (F, n=18, BCS: 3 to 4.25) and Normal (N, n=14, BCS: 2 to 3.75) groups. There was no difference in food intake between groups. F-mares kept a high BCS until foaling but the BCS of N-mares decreased from 7 months until foaling (foaling BCS: 2.75). At birth, F-placentas were 12% lighter (p<0.01), F-foals 1.4kg lighter (p<0.01) and 1.04cm smaller (p=0.04) than N-foals. There was no difference growth but F-foals had lower fasting glycemia at 1 month (p=0.03). Mares were also sorted by parity: multiparous (M, n=20) and primiparous (P, n=12). There was no difference in food intake between groups. M-mares had a high BCS (≥3.5) until foaling. P-mares were lighter (p<0.01), their BCS was lower (p<0.01) until 8 months of gestation. Gestation was shorter by 7 days (p=0.01) in P-mares. At birth, P-placentas were 16% lighter, P-foals 8.6kg lighter (p<0.01) and 5.1cm smaller (p<0.01) than M-foals. They remained lighter and smaller until 9 months of age. Fasting glycemia was higher at 1 day (p=0.02) and 3 months (p=0.08, tendency).In conclusion, we demonstrate the importance of periconceptional maternal BCS and parity on feto-placental and foal metabolism, based on a study initially aiming at exploring effects of nutrition during gestatio