top of page

Avoiding Urinary Calculi

18 JANUARY 2016

Urinary Calculi, or ‘Stones’, is a big issue to the UK lamb industry and a problem that generally increases through colder periods of the year. Kidney stones in lambs occur when insoluble salts (mostly magnesium ammonium phosphate) are deposited into the kidney or the bladder. These kidney stones can ultimately lead to death from kidney failure (uraemia), or from toxins entering the blood stream (septicaemia). This condition can account for as much as 35% of all fattening lamb deaths, with male lambs making up the largest proportion. Removal of the calculi is an expensive veterinary procedure, and so prevention is definitely better than cure through both dietary and livestock management.


Drinking an adequate amount of fresh, clean water is the single most important factor in the prevention of kidney stones. This dilutes the urine and prevents it becoming saturated with magnesium and phosphorus, reducing their deposition. Maintaining water temperature at around 10°C, can help maximise water intakes, especially when ambient temperatures are very low, whilst adding something like a tennis ball to a water trough can encourage inquisitive lambs to go to the trough and drink.


Having enough water trough space, at the right temperature is important, but so is ensuring that lambs have easy access to that trough. Freezing temperatures or troughs that are too high will restrict water intakes, so make sure the water is easy enough for stock to get to.


Offering lambs a supplementary supply of salt, or salt licks, encourages them to drink more water. Making sure the salt is accessible by all of the animals is crucial.


Making sure lambs have access to enough functional fibre helps them to ruminate and produce saliva. This increases the amount of phosphate excreted in the urine and therefore slows down the formation of the stones. Making sure lambs have access to good quality straw, separate from the bedding, can help to achieve this. This will be especially important if lambs are drinking more and bedding is wetter.


Diet is very rarely a factor that triggers problems with Urinary Calculi, but certain factors can be considered to help prevent them forming. Firstly, no additional magnesium or phosphorus should be added to diets, and the calcium to phosphorus ratio should be approximately 2:1.

Ammonium chloride should also be added to concentrate diets. This acidifies the urine and helps to prevent the formation of the stones, as long as there is enough water intake.


  • Make sure water is clean, fresh and accessible

  • Consider slightly warming the water and adding a ball to the trough to encourage drinking

  • Provide salt licks to make lambs more thirsty

  • Provide a source of roughage, such as straw, as well as providing enough bedding

  • Ensure that the mineral balance of concentrate feed is appropriate, including the addition of Ammonium Chloride

Dugdale Nutrition have a range of products for fattening lambs and for feeding to tups that contain the correct mineral balance and appropriate level of ammonium chloride to help to reduce the risk of Urinary Calculi. Speak to your local representative or call us on 01200 420200 for more information.

29 views0 comments


bottom of page