NADIS disease bulletins are written specifically for farmers, to increase awareness of prevalent conditions and promote disease prevention and control, in order to benefit animal health and welfare.

Farmers are advised to discuss their individual farm circumstances with their veterinary surgeon.

Urolithiasis (Gravel) in Rams

There were several reports during June of urolithiasis in shearling rams which were receiving supplementary concentrate feeding in preparation for autumn sales. Typically, affected animals were first seen separated from the flock, with intermittent straining, kicking at the abdomen and repeated tail swishing. The animals dribbled small amounts of blood stained urine and small rice grain - like crystals were present on the preputial hairs.

Urolithiasis is caused by blockage of the urethra of rams and wethers by a sludge of calcium, magnesium, ammonium and phosphate solutes, precipitated from urine. In some cases, blockage occurs at the vermiform appendage of the penis. These cases sometimes respond to treatment including amputation of the vermiform appendage, injections of smooth muscle relaxants and oral dosing with ammonium chloride solution to acidify the urine. In more severe cases the lower abdomen and prepuce become swollen due to leakage of urine into subcutaneous tissues, which eventually slough. In some cases the abdomen becomes distended following rupture of the bladder. The prognosis in advanced cases is poor and recovered animals are usually ill thrifty associated with kidney damage.

Most outbreaks of urolithiasis in Britain are associated with intensive concentrate feeding. Ewe rations frequently contain high levels of magnesium, so should never be fed to male sheep. Similarly, high magnesium licks for the prevention of staggers in ewes should not be available to male sheep.

Your vet can advise you about the prevention and management of urolithiasis in your flock.

RICE-LIKE CRYSTALS ON THE PREPUTIAL HAIRS OF A SHEARLING RAM

SWELLING AND NECROSIS OF THE VERMIFORM APPENDAGE OF THE PENIS

Neil Sargison BA VetMB DSHP FRCVS

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