A Master’s thesis at the College of Veterinary Medicine, Al-Qadisiyah University, entitled “Investigating Interleukin-15 Levels in Blood Serum and Their Relationship to Milk Metabolites in Dairy Cows with Negative Energy Balance Before and After Calving,” was submitted by researcher Ali Nayer Abdul-Amir and supervised by Assistant Professor Dr. Miad Jabbar Sahib Al-Hilali.

The thesis aimed to investigate interleukin-15 levels and the potential role of this interleukin in metabolic adaptation, in addition to evaluating the concentrations of some milk metabolites and studying the relationship between the concentrations of these metabolites and interleukin-15 during the transition period from the end of pregnancy to the beginning of lactation.

The most important conclusion is that interleukin-15 concentrations decrease in the blood serum of dairy cows as an immune and metabolic adaptation mechanism for energy conservation, indicating the pivotal physiological role this cytokine plays in regulating energy expenditure after calving.

The thesis recommends studying changes in digestive processes and epithelial and microbiota-related alterations to assess the digestive system’s adaptations to negative energy balance. It also recommends investigating the role of other interleukin cytokines.