Endocrine/Metabolic Traits in Goat Kids Around Weaning

Eleven Saanen kids, three days after birth, were divided into two groups: WEAN and MILK. All kids were fed goat milk until the 5th week of age, when the WEAN group began a weaning protocol. MILK group continued to receive goat milk for the entire experimental period, while WEAN group was weaned at 47 days of age. Starting from the 3rd week of age, body weight was recorded and blood samples were taken weekly, before the first meal of the day. Plasma was analysed for glucose, total protein, free aminoacid, insulin, leptin and ghrelin. Weaning did not affect plasma levels of total protein and leptin, but decreased plasma glucose and free aminoacid, and increased ghrelin concentration. Moreover, weaning decreased plasma insulin level more than three times. This result was probably the consequence of the lower concentration of plasma glucose of the WEAN group, but the effect could be enforced by the milk-borne insulin ingested by the MILK kids with the diet. Goat milk contains peptides that can pass across the intestinal epithelium and enter the systemic circulation, suggesting a possible role in accomplishing the immature ability of suckling animals to produce hormones and growth factors.