Free amino acids in plasma of neonatal calves are influenced by feeding colostrum for different durations or by feeding only milli replacer

The importance of protein and amino acid supply by colostrum intake was inv estigated in newborn calves by measuring plasma concentrations of proteins and free amino acids. Three groups of newborn calves with different colostr um supplies were created. Calves were fed colostrum twice daily for 3 days (group C-6, n = 6), or colostrum only as their first meal followed by milk replacer up to day 7 (group C-1, n = 6), or they were only fed milk replace r but no colostrum (group M, n = 5). Plasma concentrations of total protein s increased after colostrum intake on day 1 in groups C-6 and C-1 and were higher on day 7 in group C-6 than group C-1, but did not increase in group M during the first week of life. The sum of free essential, as well as free non-essential, amino acids in plasma increased after colostrum, but not af ter milk replacer intake on day 1. Free essential amino acids in plasma mer e higher on day 2 in group C-6 than groups C-1 and M. Free non-essential am ino acids in plasma on day 2 were highest in group M and higher in group C- 6 than group C-1. Plasma concentrations of glutamate were highly dependent on amounts of ingested colostrum during the first week of life, with the hi ghest concentrations in group C-6, whereas plasma glutamine concentrations on day 1 decreased after colostrum intake in groups C-6 and C-1, but not af ter milk replacer intake in group M, and were highest on day 2 in group M. Our results indicate marked effects of colostrum intake on the free amino a cid plasma pattern, especially on changes in plasma glutamine and glutamate concentrations, in neonatal calves.