Oxalate urinary calculi in beef steers.

Area of Science:

• Animal Science
• Veterinary Medicine
• Nutritional Biochemistry

Background:

• Urinary calculi (urolithiasis) are a significant health concern in feedlot cattle.
• Oxalate calculi are common and can lead to severe health issues and economic losses.
• Dietary calcium is a key factor influencing mineral balance and urolithiasis risk.

Purpose of the Study:

• To investigate the effect of varying dietary calcium levels on the incidence of urinary calculi in feedlot steers.
• To determine the relationship between dietary calcium, plasma hydroxyproline, and oxalate calculi formation.

Main Methods:

• Hereford X Angus steers were fed concentrate diets supplemented with ground limestone to achieve 0.3%, 0.6%, 0.9%, or 1.2% calcium.
• Two trials were conducted, lasting 92 and 114 days respectively.
• Urinary calculi incidence was assessed at slaughter, and plasma hydroxyproline concentrations were measured during one trial.

Main Results:

• A dose-dependent reduction in calculi incidence was observed with increasing dietary calcium.
• Steers fed 0.3% calcium had the highest incidence (12/20) of oxalate calculi.
• Higher plasma hydroxyproline concentrations, indicative of bone resorption and oxalate precursor, were found in steers fed 0.3% calcium.

Conclusions:

• Supplementing cattle diets with calcium at 0.6% or higher effectively reduces the risk of oxalate urinary calculi.
• Increased bone resorption and subsequent elevated plasma hydroxyproline in low-calcium diets contribute to calculi formation.
• Dietary calcium management is crucial for preventing urolithiasis in feedlot cattle.