Models for predicting nitrogen excretion in dairy cattle

• Grant number: 25/07543-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Animal Husbandry
• Principal Investigator: Vinícius Carneiro de Souza
• Grantee: Stella Zanini Barbosa
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

The relationship between the intensification of animal production and greenhousegas (GHG) emissions has gained prominence in discussions on sustainability, climatechange, and environmental impacts. Ruminants, especially dairy cattle, are recognizedas major nitrogen (N) emitters due to their low nitrogen use efficiency (NUE), whichexacerbates the environmental burden of livestock systems. In this context, it is essentialto explore nutritional and management strategies aimed at optimizing nitrogen utilization,thereby reducing both environmental losses and production costs. However, directlymeasuring nitrogen excretion in production systems is a complex process, highlightingthe need for robust predictive models adapted to regional conditions. In South America,this need is particularly urgent due to the scarcity of N excretion prediction models. Thus,this study aims to develop and validate predictive models for fecal, urinary, and totalnitrogen excretion, based on a database compiled from studies conducted in variousSouth American countries. The proposed models are expected to be efficient and easilyapplicable, contributing to the sustainability of dairy farming in the region