Understanding ketone bodies is crucial in the context of dairy farming. Ketone is a group of organic compounds consisting of β-hydroxybutyric acid (βHBA), acetoacetic acid (ACAC), and acetone (AC). These compounds are the product of fat metabolites during the oxidation of free fatty acid in the liver, a process known as ketogenesis. This occurs when the body uses fat as fuel for energy instead of glucose due to an imbalance between the energy taken into the body as feed and the energy lost when producing milk [1].
This imbalance triggers the liver to rapidly metabolize fatty acids into ketone bodies that circulate in the bloodstream, with the excess excreted through urine and milk. The elevated level of ketone bodies in cows can cause a disease called “ketosis.” This disease typically occurs in cows during early lactation or the first six to eight weeks. The negative impacts of ketosis may consist of reduced milk yield, impaired reproductive performance (e.g. infertility), a greater culling rate, and risk of other periparturient diseases, including displaced abomasum, lameness, mastitis, metritis, and retained placenta [2]. A concentration of βHBA above 1.2 mmol/L in blood, 0.1 mmol/L in milk and 1.5 mmol/L in urine is considered subclinical ketosis, while a level above approximately 3.0 mmol/L in the blood indicates used for clinical ketosis. It is also important to note that a single case of ketosis can cost around Canadian (CAD) CA$50 to CA$100 [3].
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