In goats, clinical obstructive urolithiasis, or urinary calculi, is most frequently seen in young, castrated males fed grain. Urinary calculi can also cause obstructive disease in intact male and may result in their destruction as breeding animals. The tendency for urinary calculi to become lodged in the urethra derives from anatomic factors and castration practices in male ruminants. Increased urine concentration from decreased water intake or increased water loss are other contributing factors. This condition is a well-recognized, highly prevalent, and costly disease of fattening steers and sheep wethers maintained in feedlot conditions and fed high a concentrate ration. This could be a potential condition in meat goats raised on a high concentration ration.
Clinical signs include restlessness and anxiety. Tail twitching is an early sign. There may be excessive vocalization and animals will strain frequently and forcefully to urinate. Marked abdominal press may produce some degree of rectal prolapse. Inexperienced owners may assume that the animals are constipated and medicate goats inappropriately rather than seeking veterinary attention. Drops of bloody urine and (or) crystals may be seen attached to preputial hairs. Animals with partial obstruction may be able to void small intermittent streams of urine, but show discomfort.
When the obstruction goes uncorrected, rupture of the bladder or urethra usually results within 24 to 48 hours. Subcutaneous filling of the preputial or perineal region becomes noticeable when the urethra is ruptured. Advanced cases often are presented in a terminal stage and the condition is fatal if left untreated.
When conservative treatment does not alleviate the condition, or if urinary tract rupture has occurred, then some sort of surgical intervention is necessary. Dietary management is the key to control and prevention of obstructive urolithiasis. Providing a continuous supply of clean, fresh water, increasing the concentration of salt in the ration up to 4% to promote water consumption and diuresis are other management factors. Prophylactic uses of urinary acidifiers have also been advocated. Continuous administration of ammonium chloride along with grain at the level of 1 to 2% has been recommended in goats. Concentrations as low as 0.5% have been used successfully to control urolithiasis in Angora goats in Texas.