The success of the control of obstetric diseases in cattle depends on the timely implementation of preventive measures, and, in cases of pathology, on diagnosis, effective obstetric care and treatment. A prominent place is given to blood tests among the methods that allow to objectively assess the state of health and the course of the pathological process in animals' bodies. The study of biochemical parameters of blood allows for the assessment of the state of metabolic processes in animals, with high accuracy in establishing the body's general condition and predicting complications and adjusting their prevention and therapy. The goal of the work: our work aimed to study the biochemical parameters of the blood of deep-calving heifers for the prediction, correction, and prevention of obstetric pathology during childbirth and puerperium. The research was carried out on deep-calving heifers of Holstein breed selected on the principle of analogues. Biochemical examination of blood serum was performed in the district laboratory of veterinary medicine. Indicators of protein and mineral metabolism were determined in the blood serum of deep- calving heifers: total protein, carotene, reserve alkalinity, inorganic phosphorus, albumin content, class M immunoglobulins. The obtained research results indicate that the total protein content corresponds to the norm in deep-calving heifers of the Holstein black-spotted breed. The protein coefficient exceeds the standard. There are pronounced deviations in the blood's biochemical parameters: low levels of carotene almost two-fold, reserve alkalinity – 1.91-fold, the total calcium content – by 16.08 % and the ratio of calcium to phosphorus by 17.78 %. Since the decrease in carotene content correlates with the predisposition to endometritis, the Holstein black-spotted breed's deep-calving heifers are prone to developing birth and postpartum pathology. For pregnant cows which are predisposed to postpartum obstetric pathology, that occur in weak parturition activity, failure to release the placenta, uterus subinvolution, endometritis and postpartum hypocalcaemia, unfavorable prognostication is the low concentration in blood plasma of general calcium, inorganic phosphorus and carotene.