Effects of Maternal Plane of Nutrition During Mid-Gestation on Beef Calf Post-Weaning Growth and Feed Efficiency, Methane Production, Insulin Sensitivity, and Carcass Characteristics

Abstract Text: Objectives were to investigate the effects of maternal plane of nutrition, during mid-gestation, on calf post-weaning growth and feed efficiency, methane production, insulin sensitivity, and carcass characteristics. Calves (n=27; steers, n=14; heifers, n=13; initial BW=239 ± 22 kg) used for this experiment were born to beef cows limit-fed for 3 planes of nutrition from 195 ± 14 to 112 ± 14 d prepartum: 100% NRC energy and protein requirement (REQ), 70% NRC requirement (70%REQ), or 130% NRC requirement (130%REQ). Calves were weaned at 198 ± 14 d of age and transitioned over 30 d to a common finishing diet. Individual DMI was recorded using GrowSafe (Airdrie, AB). At 304 ± 14 d of age, methane was collected, beginning at 3 h post-feeding, for 24 h. An indwelling venous catheter was inserted at 316 ± 14 d of age to conduct a glucose tolerance test. Plasma glucose and insulin concentrations were analyzed pre-infusion and 5, 10, 15, 20, 30, 60, 90, and 120 min post-infusion. All calves were slaughtered at 404 ± 14 d of age at an average backfat of 1.24 cm. Transition period initial BW, ADG, and DMI were not different (P≥0.39). However, G:F was greatest (P=0.01) for calves from cows fed 70%REQ and least for calves from REQ cows; calves from 130%REQ cows intermediate and different from both. In the finishing phase, treatment did not affect (P≥0.11) final BW, DMI, ADG, G:F, or residual feed intake. Residual gain tended (P=0.06) to be greater in calves from 130%REQ cows when compared to calves from 70%REQ and REQ cows. Ultrasound backfat at 299 ± 14 d post-weaning tended (P=0.06) to be greatest for calves from REQ cows and lowest for calves from 70%REQ cows, with calves from 130%REQ cows being intermediate. Maternal treatments did not affect (P=0.66) calves’ methane production. There were no effects (P>0.15) of maternal treatment on calf post-infusion glucose and insulin concentrations, glucose and insulin area under curve, or insulin to glucose ratio. Calves from REQ cows tended (P=0.08) to have greater HCW than calves from 70%REQ and 130%REQ cows. Treatment did not affect (P≥0.18) carcass backfat, yield grade, LM area, marbling score, KPH, shear force, or intramuscular fat percentage. Differing maternal plane of nutrition during mid-gestation affected transition period gain efficiency; yet, did not dramatically impact calf growth performance, feed efficiency measures, methane production, insulin sensitivity, or carcass characteristics during the finishing phase.

Keywords: Fetal programming, feed efficiency, carcass characteristics