Background: Variation in feeding methods are common in critically ill neonatal foals. However, the effect of feeding methods on energy regulation has not been investigated in foals and could be relevant to nutritional management. Hypothesis/objectives: Our objective was to investigate blood glucose (BG) and serum insulin responses in healthy foals to bolus feeding mare's milk (MM), mare’s milk replacer (MMR), and lactated Ringer’s solution (LRS; control), with direct nursing (DN) from the dam. We hypothesized that DN would enhance the glucose and insulin responses compared to bolus feeding responses. Animals: Twenty-eight healthy Standardbred foals, less than 96 hours of age, were included.
Methods: Each foal was randomly assigned to one of four treatment groups: bolus feeding 500 ml MM, MMR, or LRS via nasogastric tube, or DN from the mare for 5 minutes, each after a one-hour fast. Blood samples were collected for BG and serum insulin measurements up to 180 minutes.
Results: Area under the curve (AUC) values for BG and insulin were significantly larger in bolus-fed groups compared to DN and control. Time to maximal BG was longer for DN compared to MM and MMR, and DN maintained higher BG throughout the study period. Insulin concentrations peaked later in the DN group compared to other groups.
Conclusions: Our results suggest that while suckling is not necessary for maintaining energy regulation, the DN group demonstrated a more gradual peak in BG and insulin concentrations compared to bolus-fed groups, and sustained higher BG concentrations for a longer time.
