Assessment of calcium, phosphorus, magnesium, vitamin D and PTH levels in sera of lame horses

BACKGROUND: Minerals play vital roles in physiologic processes. Calcium, phosphorus and magnesium are common minerals. Secretion, absorption and homeostasis of these minerals are affected by associations between the active vitamin D and parathyroid hormone (PTH). OBJECTIVE: The aim of this study was to assess concentrations of vitamin D, PTH and minerals, such as calcium, phosphorus and magnesium in horse sera, as well as associations of these values with lameness in horses. In the references, the reasons for lameness can be deficiency and imbalance of minerals, and clinical observations also confirm this and there is still not enough information regarding the relationship between mineral imbalance and lameness of horses. The prominent forms of lameness include navicular syndrome, back pain, splints, ring bone, side bone, non‐infectious arthritis and bucked shins. Deficiency and inadequacy of calcium, phosphorous and magnesium have been regarded as predisposing and aggravating factors of the aforementioned diseases. MATERIALS AND METHODS: This cross‐sectional study was carried out on 60 horses, including 30 lame and 30 healthy adult horses, summer to fall 2021. Levels of calcium, phosphorus, magnesium, vitamin D and PTH were assessed in sera using automatic analyser, atomic absorption spectroscopy and commercially available kits. RESULTS: The average level of calcium was higher healthy horses than lame horses in the two seasons (p < 0.001). The average level of inorganic phosphorus in horses was higher in summer than autumn (p < 0.001). The mean magnesium concentration in healthy horses was greater than lame horses in the two seasons (p < 0.01). In this study, the mean PTH concentration in healthy horses was lower in fall than summer (p < 0.05). CONCLUSION: The low average levels of calcium and magnesium in lame horses in the two seasons indicate critical roles of calcium and magnesium in the normal function of the horse musculoskeletal system as well as prevention of lameness.