Effects of excessive energy intake and supplementation with chromium propionate on insulin resistance parameters in nonlactating dairy cows.

The objective was to compare insulin resistance parameters in cows with adequate or excessive energy intake as well as in cows with excessive energy intake receiving Cr supplementation as chromium propionate. Thirteen multiparous, nonlactating Gir × Holstein cows were ranked by BW and BCS and assigned to 1 of 3 dietary treatments on d 0: 1) diet to meet their ME requirements without Cr supplementation (MAN; n = 4), 2) diet to exceed their ME requirements without Cr supplementation (HIGH; n = 4), and 3) HIGH with 2.5 g/d of chromium propionate (HIGHCR; n = 5, with 10 mg of Cr/cow daily).

Short communication: Acute but transient increase in serum insulin reduces messenger RNA expression of hepatic enzymes associated with progesterone catabolism in dairy cows.

The objective of this experiment was to evaluate the effects of glucose infusion on serum concentrations of glucose, insulin, and progesterone (P4), as well as mRNA expression of hepatic CYP2C19 and CYP3A4 in nonlactating, ovariectomized cows in adequate nutritional status. Eight Gir × Holstein cows were maintained on a low-quality Brachiaria brizantha pasture with reduced forage availability, but they individually received, on average, 3 kg/cow daily (as fed) of a corn-based concentrate from d -28 to 0 of the experiment. All cows had an intravaginal P4-releasing device inserted on d -14, which remained in cows until the end of the experiment (d 1).