The formation of urinary calculi – or water belly – is a common metabolic issue in rams and wethers. It can also occur in females, but it's not as prevalent because the urethra is much larger in females than males.
Calculi are "stones" formed by an accumulation of minerals in the urethra, the tube that leads from the bladder to the animal's exterior.
While urinary calculi in sheep can be a serious issue, providing the proper feed and management can help stop it before it starts.
Feed a balanced ration
Urinary calculi in sheep typically occur as a result of an inverted calcium-to-phosphorus ratio in the diet. Grains and grain-based sheep feeds tend to be higher in phosphorus, the main mineral in calculi formation. Urinary calculi is seen more often in confined sheep on high-energy diets than in pastured animals consuming large amounts of forage.
The calcium content of the total diet should be 2 to 2.5 times that of the phosphorus to support a healthy balance. Also, look for a feed with an acidifier, such as ammonium chloride, to help break down stones so they can pass through the urethra. An acidifier doesn't require a veterinary feed directive (VFD).
Forages can also be a concern if they were fertilized with high-phosphorus sources, such as chicken litter. Consider testing forages and, if necessary, adding calcium sources to the diet to keep the calcium-to-phosphorus ratio balanced.
sheep feeds are developed with optimal calcium-to-phosphorus concentrations and added ammonium chloride.
Encourage water intake
Monitoring water intake is a necessary proactive measure in managing urinary calculi in sheep. Anything that causes animals to drink less water can result in more concentrated urine, increasing the chance of urinary calculi development.
Always provide sheep with an unlimited supply of clean, fresh water and consider testing your water sources for mineral imbalances that could contribute to calculi development.
Adding salt to the diet can also help increase water intake (salt doesn't contribute to the development of urinary calculi).
Other management considerations
Testosterone influences the diameter growth of the urethra, so the earlier the ram is castrated, the slimmer the urethra and the more prone it will be to blockage by a stone. It's recommended to wait until at minimum 4 months of age, and preferably 5 or 6, to castrate rams.
Symptoms of urinary calculi in sheep
Signs of urinary calculi can include restlessness, anxiety, abdominal pain (indicated by kicking of the belly) and loss of appetite. Sheep may vocalize excessively, and animals will strain frequently and forcefully to urinate. Sheep with a partial obstruction may void small, intermittent streams of urine but show discomfort.
Urinary calculi in sheep should be taken seriously as they can be life-threatening. Consult your veterinarian as soon as possible if you suspect urinary calculi in one or more of your animals.
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