Assessment of biochemical markers of connective tissue metabolism in horses with Laminitis

This study aimed to evaluate biochemical changes in urine associated with mineral and connective tissue metabolism in horses diagnosed with laminitis, and to identify potential markers for early diagnosis and monitoring of this condition. Twenty horses participated in the study: 10 clinically healthy (control group) and 10 animals with laminitis. A clinical examination was conducted, assessing behavior, posture, response to palpation, and physiological indicators. Concentrations of calcium (Ca), inorganic phosphorus (P), uronic acids, hydroxyproline, and creatinine were determined in urine samples. To eliminate the influence of variations in urine output, the ratio of each indicator to the creatinine level was calculated. Animals with laminitis exhibited the following characteristic clinical signs: weight transfer to the hind limbs; shortened gait; lameness; increased pulsation of the palmar arteries; pain; and localized temperature increase in the hoof area. Biochemical analysis of the urine revealed significant increases in calcium (+31.1%), phosphorus (+78.8%), uronic acids (+49.4%), and hydroxyproline (+50.6%) levels (p < 0.001). The Ca/P ratio decreased by 24% (p < 0.001). Relative indicators also increased: Ca/creatinine (30.2%), P/creatinine (75.0%), uronic acids/creatinine (47.4%), and hydroxyproline/creatinine (50.0%). The obtained data showed that laminitis in horses is accompanied by local and systemic metabolic disorders. Urine markers and their creatinine ratios can be used as additional, sensitive indicators of laminitis severity and treatment effectiveness