Plasma ionized calcium and parathyroid hormone concentrations in horses after endurance rides.

The study observes the behavior of plasma ionized calcium (Ca2+) and parathyroid hormone (PTH) concentrations in horses participating in endurance rides of 80 kilometers, revealing that most horses experience a decrease in calcium concentration and rise in PTH concentration after the exercise.

Methodology

• The research is a longitudinal clinical study, conducted on 28 horses.
• These horses were made to start enduring rides over 80 kilometers to evaluate changes in their plasma levels.
• Before and after the ride, venous blood samples were collected from the horses for further examination.
• The collected samples measured various aspects including plasma pH, calcium concentrations (Ca2+), parathyroid hormone (PTH), levels of inorganic phosphorus, albumin, lactate, and magnesium.

Results

• Upon analysis, the researchers revealed a significant decrease in average plasma calcium concentration following the endurance race, falling from 6.44 +/- 0.42 to 5.64 +/- 0.42 mg/dl.
• They also noted a significant increase in plasma PTH concentration, rising from 49.9 +/- 30.1 to 148.1 +/- 183.0 pg/ml, as a response to the drop in calcium levels.
• The horse’s exercise also triggered notable increases in plasma levels of inorganic phosphorus, albumin, and lactate.
• Interestingly, the levels of plasma magnesium and pH remained stable and didn’t show any variations following the exercise.
• However, it was also observed that 8 horses didn’t show the expected increase in plasma PTH concentration after the exercise. Instead, their plasma PTH concentration dropped from 58.2 +/- 26.3 to 27.4 +/- 22.4 pg/ml, despite also having decreased calcium concentrations.

Conclusion

• The research concluded that long-distance ideal for most horses was the decrease in plasma calcium concentration.
• Most horses also showed a rise in plasma PTH concentration corresponding to the dip in calcium levels, suggesting PTH’s role in regulating calcium levels and maintaining balance post-exercise.
• Some horses differed from the norm and showcased reduced plasma PTH concentrations. The reasons behind these exceptions require further investigation.