It is not yet clear how supplemental Cr may increase milk yield in early lactation. A reduction in the rate of mobilization of fatty acids from adipose tissue may allow a greater increase in feed intake, stabilize hepatic fat metabolism, and reduce hepatic ketogenesis, all working to increase milk production. If chromium is acting through glucose transporters in the adipose tissue, this speculation becomes a viable hypothesis. In the study of Besong et al. (1996)
), increased milk yield with Cr supplementation was accompanied by increased feed intake; however, feed intake was not affected by supplemental Cr in the study of Yang et al. (1996)
). Hayirli et al. (2000)
) observed an increase in DMI (as a percentage of BW) as lactation progressed, and the recent study of Smith et al. (2005)
) demonstrated an increase in DMI. It is likely that gluconeogenic precursors (such as calcium propionate) and chromium are acting via different mechanisms to elicit the same effect. The present study was done to investigate the effect on adipose tissue lipogenesis and lipolysis, as well as production effects, of feeding chromium propionate to supply 10 mg of Cr/d and calcium propionate to supply 125 g of propionate/d to high-producing dairy cattle in late pregnancy and early lactation.