Influence of corn supplementation to beef cows during mid- to late-gestation: maternal feed intake, body condition, plasma metabolites, and calf growth

To determine the effect of supplementing dry-rolled corn during mid- to late-gestation in cows fed low-quality forage on feed intake, body weight (BW), and body condition score (BCS), plasma metabolites, and neonatal growth, 47 multiparous cows (661 +/- 7.8 kg BW, 5.2 +/- 0.1 BCS, 7.5 +/- 0.2 yr of age) predominately of Angus breeding and carrying male calves were assigned randomly to supplement treatments: 0% (unsupplemented; = 24) or 0.2% of BW of dry-rolled corn (supplemented; DM basis; n = 23) from d 110 to 265 of gestation. All cows were fed the same basal forage consisting of grass hay, wheat straw, and sugar beet concentrated separator byproduct. Feed intake was monitored individually from d 110 of gestation until d 21 post-calving. Cows on the supplemented treatment were individually allowed access to 1 Insentec feeder containing corn per pen. Body weight and BCS were determined every 28 d until d 240 of pregnancy, at parturition, and at 3 wk postpartum. Jugular blood samples also were collected every 28 d during the gestation period. Calves were weighed at birth, 3 wk postpartum, and at weaning (d 168). Data were analyzed using the MIXED procedure of SAS. Corn supplementation increased (P <= 0.008) BW and BCS change during gestation and tended (P = 0.07) to decrease gestation length. Corn supplementation decreased (P = 0.002) dry matter intake (DMI) of the basal forage but did not influence (P = 0.84) total DMI (forage + corn) during gestation. Plasma glucose was not influenced (P = 0.12) by supplemental treatment and plasma urea N and non-esterified fatty acids were greater (P <= 0.02) in unsupplemented than supplemented cows. Body weight and BCS change, and DMI in cows from birth until 21 d of lactation were not influenced (P >= 0.27) by supplementation treatment. Corn supplementation during gestation did not affect (P = 0.76) calf birth weight. At 3 wk postpartum calves from supplemented cows were heavier (P = 0.04) but corn supplementation did not influence BW (P = 0.76) at weaning. Overall, supplementation of dry-rolled corn at 0.2% of BW during mid- to late-gestation likely did not elicit large enough differences in energy status to have lasting effects on calf BW. However, corn supplementation at low levels during gestation may be useful as a substitute for forage to improve energy status of the cow while decreasing the need for forage.