Effects of Late Gestation Supplementation on Dam and Subsequent Progeny Performance

Multiparous, May-calving cows (n = 652) at Gudmundsen Sandhills Laboratory, Whitman, NE were utilized over 6 production cycles to determine the effects of supplementation during late gestation on dam and progeny performance. Dams were randomly assigned to either no supplementation (NS) or supplementation with a 33% CP (DM) cube (S) from gestational d 160 - 246. This increased dietary CP and TDN approximately 1%. Supplement increased (P < 0.01) cow BW (469 vs. 455 ± 4 kg, S vs. NS), and cow BCS (4.7 vs. 4.6 ± 0.03, S vs. NS). Subsequent rebreed pregnancy rates were not impacted (P = 0.52) by treatment. Calf birth BW and dystocia rates were not impacted by supplementation. At weaning, calves born to S dams had a greater (P = 0.03) BW (201 vs. 197 ± 1 kg, S vs. NS). Following weaning, steer progeny BW and ADG were not impacted by dam’s treatment through either the development or feedlot period. Feedlot DMI for steers was also similar. Marbling score was increased (P = 0.03) for steers born to NS dams (486 vs. 463 ± 8; NS vs. S). Heifers born to S dams tended to have a greater (P < 0.10) BW at 14 mo. (320 vs. 313 ± 2 kg, S vs. NS) and at 17 mo. (361 vs. 355 ± 3 kg, S vs. NS). Heifer pregnancy rates (78 vs. 78 ± 4%, S vs. NS) and rebreed pregnancy rates as a primiparous cow (81 vs. 87 ± 5%, S vs. NS) were not impacted by dam treatment. Supplementation of the grand-dam impacted (P = 0.05) heifer’s first progeny BW at birth (30 vs. 29 ± 0.4 kg, S vs. NS). Dystocia rates were also increased (P = 0.04) in heifers whose dams were supplemented (18 vs. 9 ± 5%, S vs. NS). Late gestation supplementation increased BW over two generations, and resulted in decreased marbling score of steer progeny and increased risk of dystocia in first-calf heifers.