Healthy, productive cows are the cornerstone of profitable dairy farms, and it is the adequate management during the transition period that defines the overall lactational response and health of dairy cows. Changes happening during this period are the result of body changes, shifting hormonal balances, and nutrient requirements.
Hormonal changes during this period reduce appetite, which is combined with the fetus partially occupying the room previously destined to the pre-stomachs. The sudden onset of lactation right after calving leads to drastic changes in nutritional demands particularly to supply nutrients for colostrum and milk synthesis. All these changes result in the need of the cow to mobilize body reserves to account for the reduced nutrient intake.
From a biological response perspective, it is the mobilization of body fat stores that is the most impactful physiological change in the dairy cow. The appearance in blood of non-esterified fatty acids and subsequently beta-hydroxybutyrate are consequences of this mobilization. Excessive ketone bodies in body fluids, reflect this degree of fat catabolism, and contribute to reduced appetite and decreased milk yield.
Negative effects of ketosis
When ketone bodies concentration in blood exceed certain limits both subclinical and the clinical ketosis can manifest in cattle. One approach to improve this condition has been to artificially supplement gluconeogenic precursors to provide energy, without the need by the animal to mobilize fat excessively. It has been demonstrated that these precursors stimulate gluconeogenesis, increase plasma glucose, and decrease lipolysis.