In beef cows, grazing pastures and being feed harvested forages in the winter, chromium supplementation has improved reproductive performance. In these studies chromium was provided in a free choice mineral where salt was used to regulate mineral consumption. Stahlhutet al. (2006b) reported that chromium picolinate supplementation increased pregnancy rate in beef cows 5 years of age or younger. Chromium did not affect pregnancy rate in cows 6 years of
age or older. The improved pregnancy rate was associated with much lower plasma nonesterified fatty acid concentrations at approximately 21and 79 days after calving in chromium supplemented cows. Lower plasma
nonesterified fatty acid concentrations would suggest that chromium-supplemented cows were mobilizing less body fat to support milk
production. Consistent with the lower plasma
nonesterified fatty acid levels, chromium
supplementation reduced body weight loss in
young cows (2 and 3-year olds) after
calving. Improving pregnancy rate in young
beef cows is important because pregnancy
rate is lower in young cows compared to
mature cows.