A Survey on Prevalence and Pathological Findings of Gallstones in Lori-Bakhtiari Sheep in Iran

In a survey of 430 Lori-Bakhtiari sheep at a slaughterhouse in Iran, gallstones were found in the gallbladder of 7 sheep (1.6%). Biliary calculi were more frequent in adult and female sheep (P < 0.05). Chemical analysis of the gallstones revealed 6 sheep with pigment (bilirubin) stones and 1 sheep with cholesterol stones. Chemical composition of bile in these sheep was evaluated. Bacteriologic analysis of the bile in the affected sheep revealed bacteria (Streptococcus spp., Klebsiella spp., Escherichia coli, and Salmonella spp.) in 5 sheep. Microscopic examination of gallbladders revealed focal calcification, cystic glands, necrosis and atrophy of mucosal layer, edema, diffuse and focal infiltration of lymphocytes in submucosal layer, and hypertrophy of smooth muscles in sheep with gallstones. It was concluded that the prevalence of both types of gallstones in Lori-Bakhtiari sheep is low. Cholelithiasis can cause chronic inflammation of the gallbladder, but it is not likely to become clinically significant.