Bovine colostrum supplementation does not influence serum insulin-like growth factor-1 in horses in race training

Bovine colostrum (BC) is a commonly used food supplement in humans for both immune support and athletic performance enhancement; the latter effect has been attributed in some studies to an increase in the anabolic cytokine Insulin-like Growth Factor-1 (IGF-1). The aim of the present study was to determine the effect of BC supplementation on serum IGF-1 in racing horses. Five serum IGF-1 samples were collected from 12 horses in race training every 2 weeks over an 8-week period from November to January. Six horses received BC supplementation for 4 weeks, starting at the 2-week point. The expected seasonal IGF-1 decrease over the November to January study period was observed, but there was no effect of BC supplementation on serum IGF-1 concentrations as compared with the untreated controls.