Delayed Colostrum Feeding Affects IGF-I and Insulin Plasma Concentrations in Neonatal Calves

Abstract

In the neonatal calf, insulin-like growth factor I (IGF-I) concentrations are markedly influenced by the amount of colostrum intake after birth, although colostral IGF-I is barely absorbed. In this study we have investigated effects of delayed colostrum intake in neonatal calves on metabolic traits and on IGF-I, IGF binding proteins (IGFBP), growth hormone (GH), and insulin concentrations in plasma. Calves received colostrum of first milking starting at 2 (GrA), 6 (GrB), 12 (GrC), and 24 h (GrD) after birth. Before third colostrum intake plasma total protein concentrations were higher in GrA than in GrD and plasma glucose concentrations were higher in GrC than GrD. Plasma IGF-I concentrations at first and third colostrum intake were higher in GrA than in GrD. Plasma IGFBP-2 concentrations before first colostrum intake were higher in GrD than in GrA and GrC, and were higher before third colostrum intake in GrD than in GrA. Plasma IGFBP-3 concentrations before first colostrum intake were lower in GrD than in GrA, and before third colostrum intake were lower in GrD than in GrA and GrB. Postprandial plasma insulin concentrations after first colostrum intake were higher in GrA than in GrC and GrD. In conclusion, the plasma IGF-I and insulin status are markedly, albeit transiently, decreased in calves fed colostrum with a delay of 12 to 24 h, and the decreased concentrations of plasma IGF-I were associated with decreased IGFBP-3/IGFBP-2 ratios.

Effects of dexamethasone and colostrum intake on the somatotropic axis in neonatal calves

“…In addition, plasma IGFBP-2 concentrations in neonatal calves are regulated by the amount and time point of colostrum intake (20,23). In our study, decreased IGFBP-2 plasma concentrations in colostrumfed calves were associated with reduced hepatic IGFBP-2 mRNA levels.…”

“…Plasma GH concentrations in our study were not influenced by different feeding but were reduced by Dexa treatment. Plasma GH concentrations were barely regulated by feeding in neonatal calves (20,23,42), whereas they were influenced by feeding intensity in older cattle (7,43). Because nutrient intake was the same in the present study, nonnutritive factors such as IGFs, IGFBPs, and lactoferrin, which are present in high amounts in colostrum (3) but not in the formulas, obviously did not influence GH secretion.…”

“…Plasma concentrations of IGFBP-2 and IGFBP-3 were measured by ligand blots using 125 I-labeled IGF-I. The procedure was described recently (20,23).…”

“…Although colostral IGF-I did not affect systemic IGF-I levels in a significant manner, colostrum intake increased IGF-I plasma concentrations and hepatic IGF-I expression in neonatal calves, whereas GH plasma concentrations behaved inconsistently with respect to colostrum feeding (13,20,23,50). Besides the large nutrient supply by colostrum feeding, nonnutritive components of colostrum seem to affect the IGF-I status in neonatal calves (13).…”

IGF-I e IgG séricos e nas secreções lácteas em vacas tratadas com rbST no período pré-parto

“…Até o sétimo dia de coleta, houve queda de 98% (P<0,05) em relação à concentração inicial, com concentração média de 12,86 ng/mL de IGF-I no leite. Flutuação semelhante de IGF-I nas secreções lácteas foi encontrada por Blum & Hammon (2000), Hammon et al (2000) e Sejrsen et al (2001). A partir dos dados obtidos, pode-se sugerir que aumentos nos níveis de IGF-I na circulação materna pré-parto podem não refletir diretamente na condição de mobilização dessa proteína para a glândula mamária, pois o aumento de IGF-I nas secreções lácteas depende de um conjunto de fatores, sobretudo os níveis de hormônio de crescimento, a duração do período seco, a síntese local na glândula mamária, as características de produção e o balanço energético do animal.…”