CowNflow: A dataset on nitrogen flows and balances in dairy cows fed maize forage or herbage-based diets

Diet and animal characteristics have a significant impact on the nitrogen (N)-use efficiency by dairy cows. A dataset was built that compiles 28 N-balance experiments with Holstein dairy cows from 1983-2019, corresponding to 414 individual N flows, on a wide range of diets and animal characteristics. This dataset is composed of six Microsoft® files that correspond to six levels of information. The main file, “CowNflow_6_Cows_measurements” reports individual weekly measurements of dry matter intake, daily faeces and urine excretion, milk production and composition, cows characteristics, and chemical composition of diets, faeces, urine and milk. These raw data were used to calculate the N-balance, N-use efficiency and nutrients' in vivo total-tract digestibility. The experiments, conducted under standardised conditions, had multiples aims and offered a wide range of diets, including maize forage or herbage-based diet. The other five Excel files provide supplementary information at larger scales and describe experiment characteristics, experimental treatments, offered feeds along with their chemical composition, ingredients composition of compound feeds and cow characteristics.