Effects of Late Gestation Forage System on Dam and Subsequent Progeny Performance

Multiparous, May-calving cows (n = 652) were managed at Gudmundsen Sandhills Laboratory, Whitman, NE over six production cycles to determine the effects of late gestation grazing system on dam and progeny performance. Dams were randomly assigned to one of two forage types from gestational d 160 - 276: sub-irrigated meadow (M) or upland range (R). Average CP values for the treatment period were 17.1% and 9.4% for meadow and range, respectively. Dams grazing meadow increased (P < 0.01) BW over the treatment period (49 vs. 32 ± 2 kg, M vs. R); however, dam BCS was not impacted. Dam rebreed pregnancy rates were similar between treatments. Calves born to M dams had a greater (P = 0.04) birth BW (33.5 vs. 32.6 ± 0.3 kg, M vs. R) and weaning BW (201 vs. 197 ± 1 kg, M vs. R). Despite an increase in calf birth BW, dystocia rates were not impacted by treatment. Throughout the feedlot period, there was a tendency (P < 0.09) for DMI (12.6 vs. 12.0 ± 0.13 kg/d, M vs. R) and residual feed intake (0.073 vs. -0.110 ± 0.080 kg/d, M vs. R) to be greater for M steers. At slaughter, M steers had a greater (P < 0.05) HCW (420 vs. 409 ± 4 kg, M vs. R), empty body fat (35 vs 34 ± 0.3%, M vs. R), and marbling score (485 vs. 464 ± 8, M vs. R). Consequently, a greater percentage of M steers tended (P = 0.10) to grade USDA low Choice or greater (82 vs. 73 ± 4%, M vs. R). Heifers born to M dams had a greater (P < 0.03) BW at 14 mo. (311 vs. 302 ± 3 kg, M vs. R), and at 17 mo. (362 vs. 354 ± 3 kg, M vs. R). Prior to the birth of the first calf, M heifers had a greater (P = 0.02) BCS (5.5 vs. 5.3 ± 0.1). Percentage of heifers diagnosed pregnant did not differ (80 vs. 75 ± 4%, M vs. R), but rebreed pregnancy rates as a primiparous cow were greater (P = 0.03) for females born to M dams (90 vs. 76 ± 6%). Late gestation forage system impacted postnatal progeny growth and lipid accumulation, which may be advantageous to producers due to accelerated growth, improved carcass characteristics, and improved reproductive performance.