162 Differential Late Gestation Metabolizable Energy Intake Alters Adipose-Specific Insulin Responsiveness in Antepartum Beef Cattle

Abstract We evaluated how metabolizable energy (ME) intake influences antepartum insulin sensitivity in beef cattle. Angus-Simmental cattle (primiparous: n = 17; multiparous: 21) were randomly assigned to treatments supplying 80 (LowME, 19) or 120% (HighME, of predicted ME requirements for 53 d prepartum. At 7 antepartum, intravenous glucose tolerance tests (IVGTT) imposed by infusing 1.36 g glucose/kg BW0.75 and sampling from -3 90 min measure plasma serum non-esterified fatty acids (NEFA) concentrations. Data analyzed using PROC GLIMMIX with the fixed effects treatment, parity, time (repeated), treatment×time considering cow(treatment) as random. Baseline concentration increased (P 0.03) baseline tended increase 0.06) HighME relative LowME irrespective ≥ 0.33) whereas NEFA was elevated < 0.01) vs. HighME. Plasma glucose-insulin concentrations during IVGTT did not differ 0.25) treatment×time, parity. However, throughout be affected 0.09) interaction became similar at due having a shallower (treatment×time: P decremental response than Low cleared more quickly (75% increase; The positive incremental area-under-the-curve lesser heifers cows but had blunted ≤ 0.05) glucose-stimulated reduction clearance rate compared cows. These data demonstrate that provision may alter adipose responsiveness respond excess differently