Indian Journal of Veterinary Surgery

The aim of the present investigation was to study the composition and growth pattern of solid caprine urethral calculi and urethral plugs by scanning electron microscopic (SEM) examination. Four randomly selected urethral calculi and 2 urethral plugs collected surgically from the goats suffering from obstructive urolithiasis were subjected to scanning electron microscopic study. Surface SEM morphology was studied in each intact calculus and then the solid calculi were transected into 2 parts to study the internal composition and growth pattern. One part of the transected calculus was studied as such and the other part was decalcified with 0.25 m EDTA before it was subjected to SEM examination. The urethral plugs were studied without decalcification. Two calculi had clear nidus surrounded by variable size and number of laminae. One calculus did not have a clear nidus and was made up of whorls of laminae. Another calculus was a congregation of many calculi, attached to each other with fine cementing material. There was abundance of coffin lid shaped struvite crystals in the nidus as well as in the laminae of the 4 calculi. Small amounts of calcium phosphate, calcium oxalate and organic matrix were also present at a few places between the struvite crystals. SEM study of caprine calculi revealed that the calculi were mixed in nature but the struvite was the major ingredient of these calculi. Urethral plugs were mainly amorphous in nature. They had globular surface without the evidence of crystallization.