Insulin-like Growth Factor-I and Its Binding Proteins in Colostrum Compared to Measures in Serum of Holstein Neonates1

• Published in: Journal of dairy science Vol. 86; no. 6; pp. 2022 - 2029
• Main Authors: Sparks, A.L., Kirkpatrick, J.G., Chamberlain, C.S., Waldner, D., Spicer, L.J.
• Format: Journal Article
• Language: English
• Published: Champaign Elsevier Inc 01.06.2003; American Dairy Science Association
• Subjects: colostrum; IGF binding protein; IGF-I; neonatal calf; IGF binding protein; IGFBP; IGF-I; ADU; colostrum; GGT; IgG; neonatal calf
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(03)73791-6

Colostral insulin-like growth factor-I (IGF-I) may be beneficial in the development of gastrointestinal tracts of bovine neonates. Thus, the purpose of this study was to examine relationships among concentrations of IGF-I and IGF-binding proteins (IGFBP) in colostrum used at two initial feedings and serum concentrations of IGF-I, IGFBP, total protein, gamma glutamyltransferase (GGT), and immunoglobulin G at 0 and 48h after birth in Holstein neonates. Calves (n = 22) were separated from dams immediately after birth. Blood samples were taken before initial feeding and at 48h after birth. Calves were fed 2L of colostrum twice and milk replacer thereafter. Linear regression of serum IGF-I at 48h and colostral IGF-I revealed a significant positive relationship (R2 = 0.204). Serum IGFBP-3 at 48h and colostral IGFBP-3 also had a positive relationship (R2 = 0.143). However, linear regression of colostral IGF-I on the difference in serum IGF-I at 48 and 0h was not significant. Calves were assigned to group 1 (0-h serum IGF-I<10ng/ml; n = 11) or group 2 (0-h serum IGF-I≥10ng/ml; n = 11) for further analysis. There were no differences in serum IGF-I or IGFBP-2, -3, -4, and -5 concentrations at 48h between groups 1 and 2. Correlation coefficients revealed negative relationships of serum IGF-I at 0h to the difference between serum IGF-I at 48 and 0h (r = −0.824), as well as birth weight of the calf to the amount of GGT at 48h (r = −0.604). Females had lower birth weights than males, but sex of calf did not affect serum measures. At 0h, but not 48h, total serum protein was correlated to serum GGT concentrations (r = 0.573). From indirect evidence, absorption of colostral IGF-I and IGFBP-3 into systemic circulation may occur, but relative importance compared to endogenous sources is uncertain.