Dairy cattle are susceptible to increased incidence and severity of disease during the periparturient period. Increased health disorders have been associated with alterations in bovine immune mechanisms. Many different aspects of the bovine immune system change during the periparturient period, but uncontrolled inflammation is a dominant factor in several economically important disorders such as metritis and mastitis. In human medicine, the metabolic syndrome is known to trigger several key events that can initiate and promote uncontrolled systemic inflammation. Altered lipid metabolism, increased circulating concentrations of non-esterified fatty acids and oxidative stress are significant contributing factors to systemic inflammation and the development of inflammatory-based diseases in humans. Dairy cows undergo similar metabolic adaptations during the onset of lactation, and it was postulated that some of these physiological events may negatively impact the magnitude and duration of inflammation. This review will discuss how certain types of fatty acids may promote uncontrolled inflammation either directly or through metabolism into potent lipid mediators. The relationship of increased lipid metabolism and oxidative stress to inflammatory dysfunction will be reviewed as well. Understanding more about the underlying cause of periparturient health disorders may facilitate the design of nutritional regimens that will meet the energy requirements of cows during early lactation and reduce the susceptibility to disease as a function of compromised inflammatory responses.

Dairy cattle are susceptible to increased incidence and severity of both metabolic and infectious diseases during the periparturient period. A major contributing factor to increased health disorders is alterations in bovine immune mechanisms. Indeed, uncontrolled inflammation is a major contributing factor and a common link among several economically important infectious and metabolic diseases including mastitis, retained placenta, metritis, displaced abomasum, and ketosis. The nutritional status of dairy cows and the metabolism of specific nutrients are critical regulators of immune cell function. There is now a greater appreciation that certain mediators of the immune system can have a reciprocal effect on the metabolism of nutrients. Thus, any disturbances in nutritional or immunological homeostasis can provide deleterious feedback loops that can further enhance health disorders, increase production losses, and decrease the availability of safe and nutritious dairy foods for a growing global population. This review will discuss the complex interactions between nutrient metabolism and immune functions in periparturient dairy cattle. Details of how either deficiencies or overexposure to macro- and micronutrients can contribute to immune dysfunction and the subsequent development of health disorders will be presented. Specifically, the ways in which altered nutrient metabolism and oxidative stress can interact to compromise the immune system in transition cows will be discussed. A better understanding of the linkages between nutrition and immunity may facilitate the design of nutritional regimens that will reduce disease susceptibility in early lactation 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.

The composition of fatty acids in the diets of both human and domestic animal species can regulate inflammation through the biosynthesis of potent lipid mediators. The substrates for lipid mediator biosynthesis are derived primarily from membrane phospholipids and reflect dietary fatty acid intake. Inflammation can be exacerbated with intake of certain dietary fatty acids, such as some ω-6 polyunsaturated fatty acids (PUFA), and subsequent incorporation into membrane phospholipids. Inflammation, however, can be resolved with ingestion of other fatty acids, such as ω-3 PUFA. The influence of dietary PUFA on phospholipid composition is influenced by factors that control phospholipid biosynthesis within cellular membranes, such as preferential incorporation of some fatty acids, competition between newly ingested PUFA and fatty acids released from stores such as adipose, and the impacts of carbohydrate metabolism and physiological state. The objective of this review is to explain these factors as potential obstacles to manipulating PUFA composition of tissue phospholipids by specific dietary fatty acids. A better understanding of the factors that influence how dietary fatty acids can be incorporated into phospholipids may lead to nutritional intervention strategies that optimize health.