Reducing diseases in dairy cows can decrease greenhouse gas emissions
The objectives of this thesis were to estimate the impact of diseases in dairy cows on greenhouse gas emissions, and to understand the relation between the impact of diseases on greenhouse gas emissions and economic performance. To do so, a model was developed to simulate the dynamics of diseases and associated production losses. This model was combined with a life cycle assessment to quantify the impact of subclinical ketosis, clinical mastitis, and foot lesions on greenhouse gas emissions along the dairy production chain. Compared to a healthy cow, a case of subclinical ketosis increased emissions per unit of milk by 2.3%, a case of clinical mastitis by 6.2%, and a case of foot lesions by 1.5%. An economic analysis showed that the total costs of a case of subclinical ketosis were €130. A reduction in milk production had the highest impact on the economic performance, whereas removal of cows and discarded milk had the highest impact on increase in greenhouse gas emissions. Diseases in dairy cows increase greenhouse gas emissions by approximately 0.4 Mton per year, and therefore, reducing diseases can have an important contribution to the Dutch emissions reduction aim of 3.5 Mton from agriculture in 2030.