The nexus between nutrient metabolism, oxidative stress and inflammation in transition cows

Increased incidence of several economically important diseases (i.e. mastitis, metritis, displaced abomasum and ketosis) causes significant animal welfare problems and production losses in transition dairy cattle and decreases the availability of safe and nutritious food for a growing global population. A major underlying factor responsible for the development of transition cow disorders is metabolic stress, which occurs when cows fail to adapt physiologically to an increase in nutrient requirements needed for parturition and the onset of copious milk synthesis and secretion. Metabolic stress can be characterised as resulting from the combined effects of altered nutrient metabolism, dysfunctional inflammatory responses, and oxidative stress. Together, these factors form destructive feedback loops that exacerbate metabolic stress and cause health disorders in transition cows. A better understanding of how nutrition and immunology interact to influence metabolic stress will facilitate the development of control programs to improve transition cow health. The ability to detect signs of metabolic stress early enough in the dry period to implement needed management adjustments before calving will be the key to successful monitoring and intervention programs.