Effects of Maternal Plane of Nutrition During Late 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 late gestation, on calf post-weaning growth and feed efficiency, methane production, insulin sensitivity, and carcass characteristics. Calves (n=28; steers, n=17; heifers, n=11; initial BW=251±25 kg) used for this experiment were born to beef cows limit-fed for 3 planes of nutrition from 92±6 to 9±6 d prepartum: 100% NRC energy and protein requirement (REQ), 70% NRC requirement (70%REQ), or 130% NRC requirement (130%REQ). Calves were weaned at 199±6 d of age and transitioned over 28 d to a common finishing diet. Individual DMI was recorded using GrowSafe (Airdrie, AB). At 305±6 d of age, methane was collected, beginning at 3 h post-feeding, for 24 h. An indwelling venous catheter was inserted at 315±6 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 388±6 d of age at an average backfat of 0.96 cm. Calf BW at the beginning and end of the transition period was not different (P≥0.37). Transition period ADG was greater (P=0.05) for calves from cows fed 130%REQ than calves from 70%REQ cows, with calves from REQ cows intermediate and not different from either. There were no differences (P≥0.12) in transition period DMI or G:F. In the finishing phase, there were no differences (P≥0.41) in final BW, DMI, and ADG; however, G:F was greater (P=0.05) for calves from 70%REQ cows than calves from REQ cows, with calves from 130%REQ cows intermediate and not different from either. Residual feed intake and residual gain were improved (P<0.01) in calves from 70%REQ cows compared to calves from REQ and 130%REQ cows. Treatment did not affect (P=0.48) methane production. Post-infusion glucose concentration was not different (P=0.63); however, post-infusion insulin concentration was greater (P=0.01) for calves from REQ cows than calves from 70%REQ and 130%REQ cows. There were no differences (P≥0.19) in glucose or insulin area under curve and insulin to glucose ratio. Treatment did not affect (P≥0.12) HCW, backfat, yield grade, LM area, marbling score, KPH, shear force, or intramuscular fat percentage. Calves born to 70%REQ cows were more efficient during the finishing phase, and calves born to REQ cows had greater post-infusion insulin concentrations. However, maternal plane of nutrition had no effect on final BW, methane production or carcass characteristics.

Keywords: Fetal programming, feed efficiency, insulin sensitivity