Livestock systems are typically managed to provide a least-cost ration balancing energy, protein, minerals, and vitamins in the diet according to the estimated requirements of the average animal. Optimizing the utilization of available food and its quality is important to the profitability of any production system, as well as helping to minimize the proportion of nutrients consumed by the animal that are lost to the environment. For a dairy cow, 35% of energy consumed in the diet can be lost in the form of enteric methane, faeces or urine and 77% of nitrogen consumed can be excreted in faeces or urine. Furthermore, poor quality food can impair the production and wellbeing of the animal which leads to an inability to achieve desired intakes of food, therefore resulting in increased land required and reduced nutrient efficiency.