FEATURES
• In Memoriam
• WNAF Dedicated to Larry
   Kirk
• Problems with Feeding Grain
• Reproductive Systems
• Same Old Cycle
• Trace Mineral Efficiencies
• Urinary Stones In Cattle

Often called “water belly” because of the distended bladder that eventually ruptures and releases urine into the abdomen, this condition affects steers and bulls more frequently than cows or heifers. Females have a larger, shorter urinary passage and it rarely becomes blocked.

If even one animal in the herd suffers from this problem, however, it may mean that the herd diet is out of balance and other animals may be harboring urinary stones. Water belly occurs most frequently in steers between 5 and 18 months of age. This situation is more common in feedlot animals, but sometimes afflicts animals at pasture.

The blockage is a life-threatening problem, caused by eating feeds that contain unbalanced quantities of certain minerals. The various minerals in feed are absorbed from the intestine into the bloodstream where they find their way to various parts of the body to assist in certain functions. Iron, for instance, helps create healthy red blood cells to carry oxygen. Calcium and phosphorus help build bones. Any extra minerals not needed by the body are filtered out by the kidneys and excreted in urine.

If the concentration of certain minerals in the urine reaches a saturation point, however, the solution starts to form crystals. This happens more readily if the animal is short on water and the urine becomes more concentrated than normal. This is similar to what happens when salt water evaporates, leaving crystals of salt. If the animals are drinking plenty of water, the urine is more dilute and the minerals rarely precipitate out of solution.

If urine stays quite concentrated most of the time, however, mineral crystals in the kidney or bladder increase in number and size and start clumping together to form stones. Any stones that stay in the bladder rarely cause problems and may be there for the rest of the animal’s life without symptoms.

In an animal with a short, large-diameter urethra (such as a cow or heifer) stones may readily pass on out with the urine. In the female, the passage from the bladder to the outside opening is very short and direct. But in a male, the urethra is much longer and it makes a sharp bend. It also becomes quite narrow where it passes through the penis. A stone may become caught in this narrow passage and block it. Steers are most commonly affected because they have the smallest diameter urethra, especially if they were castrated at a young age. The urethra does not enlarge very much as the animal grows. The urethra of a bull is a little larger in diameter, but not nearly as large as in a female.

Animals that don’t drink enough water, or individuals that consume an excessive amount of minerals (especially phosphates) are more likely to develop stones because the urine is more concentrated. Some people think that hard water (containing a high level of minerals) can lead to stones, but hard water generally contains calcium and magnesium, which actually helps protect cattle against formation of phosphate stones.

Symptoms
If the urethra is blocked by a stone, the bladder cannot empty, and grows larger. Urine is continually formed by the kidneys and routed to the bladder, which can no longer empty through the blocked tube. The distended bladder puts pressure on other organs in the abdomen, causing discomfort at first, and eventually extreme pain. The affected animal will lick or kick at his belly, stomp or tread with his hind feet, and constantly switch his tail. Attempts to urinate may be accompanied by straining. If the stone does not completely obstruct the urethra, the steer may dribble a little blood-stained urine, but he is still in a lot of pain. He tries repeatedly to urinate, and may grind his teeth while trying to pass urine.

As pressure builds up in the distended bladder, it eventually ruptures. This gives instant relief to the animal because the pressure is gone. He quits kicking or showing other signs of distress. But this relief is temporary and the start of a more serious problem. The urine from the ruptured bladder now flows into the abdominal cavity or fills the tissues around the penis. Swelling caused by this fluid seepage may extend under the belly skin toward the chest.

In a few hours, toxins and other waste materials that were filtered out of the body via the kidneys and into the urine are now absorbed back into the bloodstream and start to slowly poison the animal. An affected animal usually becomes dull and stops eating, and may go into shock, or he becomes weak and eventually dies. Death usually occurs within 48 hours after the rupture.

Treatment
At first sign of water belly, the options are to either butcher the animal or have your veterinarian try treatment, or perform surgery. If you detect the problem early enough, often the best solution is to salvage the animal by slaughter. If this is not feasible, consult your veterinarian for advice on treatment and/or surgery.

Urinary tract relaxation may help keep the urethra as open as possible, to allow passage of stones. Giving the steer ammonium chloride may help make the urine more acid, to dissolve any phosphate stones. Surgery is probably the most effective treatment, if performed soon after the problem is discovered, but may not save the animal if the condition has been going on for several days and the animal’s health is already compromised. If the bladder has already burst, there is generally no hope for recovery.

The surgical procedure is merely a temporary solution to keep the steer alive, enabling him to recover and grow large enough to be butchered. The vet will make an incision below the rectum so the penis can be dissected out through the underlying tissues and pulled out backward through the opening. The urethra in the penis is then opened up to allow urine to drain out. This hole in the urethra is kept open by stitching it to the skin. Since the new opening is above the blockage, it creates a new exit for urine coming from the bladder. The steer will then urinate through this hole just below the anus, similar to the route of urination in a heifer.

If the surgical site heals properly and the hole stays open, the steer can continue to function, though the urine will usually run down the back of his hindquarters. This emergency procedure can buy time, however, to get the steer over the problems caused by the stone, including any tissue residues of medication and urine, and perhaps give him enough time to finish growing to better butcher weight.

Prevention
In feedlot cattle, a ration balanced for calcium and phosphorus (2 parts calcium to 1 part phosphorus) will help reduce the risk for stone formation. Feeding alfalfa, which has a high level of calcium and lower level of phosphorus, is beneficial. Adding salt and a little ammonium chloride to the feed may also help. The diet should always be well balanced, with adequate vitamin A. Plenty of clean, warm water should be supplied in cold weather so the animals will drink enough.
In pastured cattle, make sure they always have salt and plenty of clean water. Pastures that contain plants that are high in silicates and oxalates may be risky for steers and should only be used by cows and calves unless you can supplement with alfalfa or other legumes to reduce the intake of siliceous plants.

BVD OR IBR MAY PLAY A ROLE IN FORMATION OF STONES
In many geographic regions the incidence of urinary stones has decreased within the past 20 years, possibly due to better herd health and vaccinations. Some veterinarians feel there is a possibility that BVD and/or IBR virus (both of which can be found in the kidneys if an animal has been exposed to these diseases) might cause the sloughing of small cells or tissues from the lining of this organ. These cells or bits of tissue could then serve as something for minerals to cling to and build up on. Some herds or feedlots that have had a diligent health program to eradicate and/or protect against these viral diseases now seem to have less incidence of water belly than they had in the past.

TWO KINDS OF STONES
Phosphate stones are most common when steers are fed grain. The high levels of carbohydrates cause an increase in muco-proteins in urine, and grain is high in phosphorus. In urine that is slightly alkaline, these two factors may result in phosphate stones, which are relatively soft.
Silicate stones are more common when animals are out on pasture. Some forage plants contain high levels of silica, as do some water sources. Silicate stones, which are very hard, tend to form when urine is slightly acidic.