Acidosis as one of the key factors in the development of laminitis in highly productive dairy cows

Abstract

One of the main causes of lameness in cows is laminitis - an aseptic diffuse inflammation of the claw horn dermis. Laminitis is more common in high-yielding dairy cows and first-calf heifers. The research goal was to investigate the mechanism of metabolic disorders, clarify the conditions for the development of metabolic pathologies, and provide a rationale for the use of a combination of therapeutic and preventive measures in high-yielding dairy cows. The objective was to recreate conditions that contributed to the development of moderate acidosis leading to laminitis, analyze the clinical picture in cows with metabolic disorders, and develop treatment and preventive measures. To study the causes of laminitis in more detail, a model of acidosis was created in Holstein cows by introducing easily soluble carbohydrates at a dose of 16.25 g kg of live weight. Biochemical studies of blood, urine, and rumen contents were conducted. Biochemical studies of the blood of animals with acidosis revealed increased content levels of lactic acid to 4.18 ± 0.13 mmol L and higher. There were increased levels of total protein (96.23 ± 1.75), ALT (49.4 ± 1.43), and bilirubin (16.6 ± 1.02) which was indicative of impaired liver function and structure due to acidosis. The blood pH value was reduced from 7.423 to 7.145 which corresponded to acidemia. During the clinical examination of the animals, it was found that there was increased local temperature, swelling, hyperemia, and tenderness of the tissues of the coronet and the second and fifth digits on the palmar side of the dew claws as well as pulsation of the common digital arteries which were symptoms of laminitis. The conducted research on the experimental simulation of the disease allows identifying the relationship of acidemic syndrome in cows and the appearance of laminitis signs. The stages of laminitis development were studied in detail and a treatment regimen for the pathology was proposed.