Review: A hierarchical research model to foster dialog between grazing ecology and beef cow energetics to support ecological intensification of native grassland.

Abstract

Cow-calf systems grazing native grasslands must transition toward improved economic performance simultaneously with the conservation and improvement of ecosystem services they provide. We present an innovation model with this objective based on a hierarchical model that links functional relationships between state variables, grazing experiments and its validation, and co-innovation at the farm level. This paper describes the hypotheses, designs, and results of the studies, and the role of grazing ecology and herbivore nutrition to support the process of ecological intensification of livestock systems on native grasslands. The model consists of records analysis, grazing experiments, employment of econometric and simulation models, and proposal of validation and co-innovation studies in production systems. Analysis of records could identify forage height and cow body condition score at calving as state variables and their relationship with pregnancy rates. Grazing experiments were designed to identify seasonal levels of state variables, and a management model was proposed to enhance cow-calf performance. The next stage examined the effects of Forage Allowance (FA) levels (Low [3] vs High [5] kg DM/kg BW) on state variables, main ecosystem processes, and beef production per cow and hectare. High FA increases forage production, forage intake, and energy use efficiency of cows, which explains the 30-50% improvements in meat production per hectare. The increase in FA was associated with improved forage structure, cow DM intake, and levels of metabolic hormones. A validation of the management proposal and 'optimal' FA coefficients from analytical research confirmed improvements in productive and economic commercial systems results. Co-innovation on 60 livestock farms led to better economic results through increased meat production per hectare without elevating production costs. This adjustment, along with a small reduction in stocking rate, helps account for the reduction in CO₂ equivalent emissions per product unit. The innovation platform promotes a hierarchical model linking Grazing Ecology and Herbivore Nutrition and contributes to improving the sustainability of livestock systems on native grasslands.