Glucose and insulin curve in pregnant mares and its relationship with clinical and biometric features of newborn foals

The effects of obesity and insulin dysregulation on mare reproduction, pregnancy, and foal health: a review

Obesity is a growing welfare concern in modern equine populations and predisposes horses to disturbances in energy metabolism such as insulin dysregulation. However, equine metabolic syndrome has only been recognized in recent decades. Functioning energy metabolism is pivotal to normal body homeostasis and affects essentially all organ systems, including reproduction. Previous literature suggests that obesity has an effect not only on the reproductive processes in mares but also on offspring health, predisposing the offspring to later-onset orthopedic and metabolic problems. This review focuses on the effects of obesity, insulin dysregulation and hyperinsulinemia on the reproductive functions of mares and the implications on foal health before and after birth. The points of interest are the cyclicity and ovarian function, uterine environment, gestation, the postpartum period, and the newborn foal. The aim is to review the current state of knowledge, and identify outstanding questions that could stimulate future research. This topic is important not only from the equine industry and production perspective but is also relevant for the welfare of future populations and individuals.

Energy and mineral metabolism of peripartum mares and foals of the Quarter Horse breed

BACKGROUND

Several studies have demonstrated variations in peripartum blood biochemical analytes used to monitor the health status of mares and their foals of different breeds.

OBJECTIVES

We aimed to characterize the physiologic changes of peripartum energy and mineral metabolism in healthy Quarter Horse mares and their neonatal foals.

METHODS

Blood samples were initially collected from 17 mares on days 60 and 30 prepartum, and from mares and their foals on the day of parturition (after colostrum ingestion), and on days 15, 30, and 60 postpartum. The serum concentrations of calcium, phosphorus, magnesium, total cholesterol (T-Cho), triglyceride, beta-hydroxybutyrate (BHBA), and nonesterified fatty acids (NEFA) were measured using commercial kits. Statistical differences were analyzed using one-way ANOVA followed by Tukey's test (parametric variables) or the Kruskal-Wallis test followed by Dunn's multiple comparison test (nonparametric variables).

RESULTS

Fourteen of 17 healthy Quarter Horse mares and their neonatal foals remained in the study until termination. Serum BHBA, T-Cho, and calcium concentrations in mares showed significant differences during the observation period. Serum BHBA concentrations increased from 60 days prepartum to 60 days postpartum. Postpartum serum T-Cho and calcium concentrations significantly decreased until day-30 postpartum. In the foals, NEFA, T-Cho, calcium, and magnesium concentrations significantly differed between sampling times. In the foals, serum NEFA concentrations decreased from parturition until day-60 postpartum, while serum T-Cho, calcium, and magnesium concentrations were lowest at day-30 postpartum.

CONCLUSIONS

The temporal changes observed in the blood biochemical analytes of this study could be used to improve the clinical evaluation of periparturient mare and neonatal foal Quarter Horses.

Nutrition of Broodmares

Forage availability should cover most needs for mares bred during spring and summer. Out-of-season breeding, lack of access to pasture, or good quality forage calls for nutritional supplementation. Current evaluations of broodmare needs are based on fetoplacental tissue requirements, but do not consider endocrine changes or that the maternal diet quality affects long-term foal health. This article reviews pregnant mares' current nutritional recommendations. Secondly, fetoplacental developmental stages during gestation are outlined, defining critical periods in the context of the developmental origins of health and disease. Last, examples of how maternal nutrition affects long-term foal health are presented.