Prevention of Urolithiasis in Lambs

6 November 2018

Urinary stones / urolithiasis / water belly can be a problem with rapidly growing lambs fed high amounts of concentrates.

Crystals can be formed in the bladder, which block the flow of urine in male lambs and if the urethra ruptures under pressure, this results in ‘water belly’.

As water belly is life threatening and usually requires surgery to unblock the crystals, nutritional prevention is key. Strategies to help prevent urolithiasis are ensuring a good water supply, adding salt to the diet, using anionic salts, and using a correctly balanced mineral to ensure the mineral content in the diet is correct.

  1. Fresh clean water Fresh clean water must always be available to ensure lambs drink water to help dilute and flush crystals from the bladder.
  2. Adding salt to the ration Salt (sodium chloride) can be added to the diet to promote water intake. This keeps the bladder flushed, reducing crystal formation. Salt can be gradually increased in the diet to a final level of 4%.
  3. Urine acidifiers Feeding anionic salts, such as ammonium chloride or calcium chloride, lowers the pH (acidifies) the urine, which helps prevent crystals forming in the bladder.
  4. Ensuring the mineral content of the diet is correct The most common crystal in lambs urine is a struvite crystal, composed of magnesium ammonium phosphate hexahydrate.

    To help prevent these crystals forming keep:
    • the dietary magnesium content below 0.2%
    • the dietary phosphate content below 0.6%
    • the dietary calcium : phosphorus ratio above  2 : 1