Exploring Relationships Between Cow-Calf Management Systems as Affected by Protein Level and Methionine Supplementation in Late Gestation on Cow-Calf Performance Prior to Weaning
The objective of this study was to assess impacts of protein and methionine nutrition during gestation and two lactational management systems on the performance of cow-calf pairs prior to weaning. Late gestation beef cows were fed to meet 90%, 100%, or 110% of metabolizable protein requirements, with(without) rumen-protected methionine. Postpartum, cow-calf pairs were managed in drylot and fed a ration formulated to meet nutrient requirements, or rotationally grazed on pasture. Prepartum nutrition did not impact calf performance prior to weaning, but may have affected cow performance during lactation. Both gestational protein supply and lactational management system altered methane emissions throughout lactation. Rotationally grazing cow-calf pairs improved pre-weaning calf performance, but reduced cow gains throughout lactation. In addition, nutrition and management did not impact reproductive performance. This study demonstrated that managing cow-calf pairs on pasture prior to weaning produced healthier and heavier calves, without sacrificing dam reproductive performance.