Effect of weaning and milk replacer feeding on plasma insulin and related metabolites in Saanen goat kids

Thirty-six three-day old Saanen goat kids were divided into four groups (GM, WGM, MR and WMR). GM kids received goat milk to age 48 days. WGM group was initially fed goat milk, but started weaning at 25 days and was completely weaned by 40 days. MR kids were fed a milk replacer to age 48 days. WMR kids were initially fed the milk replacer and then subjected to the same weaning protocol used for WGM kids. During the experimental period, total consumption per group was recorded daily. Weekly, body weights were recorded and plasma samples were taken and analyzed for glucose, free amino-acids and insulin. Weaning significantly decreased dry matter intake in WGM and WMR. Nonetheless, no difference was observed in body weight between the four groups, throughout the study period. Weaning decreased plasma glucose, amino-acids and insulin in WGM and WMR groups. Soon after the first week of treatment, plasma glucose and free-amino acids began to be lower in milk replacer-fed kids (MR and WMR), in comparison to goat milk-fed ones (GM and WGM). Results suggest that weaning affects glucose and amino-acid metabolism and insulin secretion, while milk replacer feeding reduces plasma glucose and free amino-acids, without affecting insulin.