Dairy barns emit harmful gases like ammonia and greenhouse gases, which impact the environment. By adjusting the cows' diet and how manure is managed, researchers found that they could reduce these emissions. Cows fed a low-protein diet produced less ammonia, regardless of manure management. High-protein diets led to higher ammonia emissions, especially with solid manure. Methane emissions were higher with solid manure due to litter accumulation. Overall, the study suggests that accurately measuring ammonia emissions requires considering the variability in nitrogen excretion.