Epidemiological Evaluation Of Uroliths In Selected Animals

Thumbnail Image

Persistent link to this item

View Statistics

Journal Title

Journal ISSN

Volume Title


Epidemiological Evaluation Of Uroliths In Selected Animals

Published Date




Thesis or Dissertation


ABSTRACT This dissertation examined the predominant minerals, as well as the risk and protective factors for urolith formation in ferrets, goats, sheep and horses. Sterile struvite was the predominant mineral in uroliths in ferrets. The mean age of ferrets with struvite uroliths was 3.6 ± 2.8 years and range (0.2 to 9.8 years). Cystine comprised 70 of the 435 (16%) uroliths retrieved from ferrets. The mean age of ferrets with cystine uroliths was 4.1 ± 1.5 years and range (0.5 to 9 years). This was surprising, as one might expect an earlier onset of clinical manifestations of a probable genetic disorder, with the life span of ferrets being reported to be between 5 and 11 years. Cystine uroliths are not rare at all in ferrets as was originally thought. Genetic factors associated with cystine urolithiasis have not yet been reported in ferrets, but a familial pattern of inheritance determined to be a major underlying factor in cystine urolithiasis in dogs and humans suggests that this may be a factor in ferrets and that the parent stock of ferrets in the present study may have been inbred. The mean age of goats with CaCO3 urolith was 3.8 ± 1.8 years and range (0.3 to 14 years). Males are at increased odds for CaCO3 urolith than females. Goats of African descent had a higher risk of developing calcium carbonate uroliths than did goats of non-African descent. The mean age of goats with silica uroliths was 3.1 ± 1.2 years and range (0.2 to 10 years). The bulk of goats with silica were fed grass/pasture (22%). Silica urolith submissions retrieved from goats and submitted to the MUC decreased from 20% between1984 and1998 to 11% between1999 and 2012. More than 57% percent of goats with struvite uroliths were < 1 year of age. Calcium carbonate uroliths rose significantly in North America but not in Europe and Asia from 40% in 1984 to 1998 to 45% in 1999 to 2012. Struvite and magnesium calcium phosphate apatite uroliths decreased significantly in North American continent respectively from 8% and 9% in 1984 to 1998 to 3% and 4% respectively in 1999 to 2012. The mean age of sheep with CaCO3 urolith was 3.4 ± 1.4 years and range (0.8 to 11 years). Calcium carbonate uroliths were common in Dorset, Suffolk and mixed breeds of sheep. These 3 breeds comprised 15 of 29 (52%) of case sheep with calcium carbonate uroliths with data available. The mean age of sheep with magnesium calcium phosphate carbonate (MCPC) uroliths was 1.6 ± 1.2 years and range (0.2 to 9 years). Rambouilette, Suffolk and Hamshire sheep breeds were at high frequency for magnesium calcium phosphate carbonate urolith formation. These 3 breeds comprised 23 of 31 (74%) of case sheep with MCPC uroliths with data available. Magnesium calcium phosphate carbonate uroliths were commonly retrieved from sheep < 1year of age and comprised 23 of 38 (60.5%) of sheep with this condition with age reported. MCPC is more common in male and sexually intact sheep. The mean age of horse with CaCO3 urolith during the study was 13 ± 1.8 years and range (0.3 to 36 years). Quarter and Thorough bred horses comprised 151 of 292 (52%) of all horses with CaCO3 urolith. Horses between the ages of 6 and 17 years old comprised 197 of 323 (61%) horse cases with ages reported. Male horses had higher frequency for CaCO3 uroliths compared to females. Neutered horses had higher frequency for CaCO3 uroliths than sexually intact. Calcium carbonate uroliths in horses were more likely to be retrieved from the lower portions of the urinary tract (85%) of case horses than from the upper portions of the urinary tract (14%). Three (1%) were retrieved from both upper and lower tracts. A typical horse with CaCO3 urolith is a neutered male between the ages of 6 and 17 years old. Seventy-six of 80 (95%) CaCO3 uroliths were retrieved from horses between 1981 and 1997 and submitted to the MUC, while between 1998 and 2014 the amount retrieved from case horses were 227 of 278 (97%) CaCO3 and submitted to the same laboratory. This study identified risk factors associated with urolithiasis in ferrets, goats, sheep and horses; however, these associations do not allow conclusions regarding cause-and-effect relationships. Evaluation of risk and protective factors through epidemiological studies may be useful in the development of recommendations for the prevention and control of urolith formation in these selected animals.


University of Minnesota Ph.D. dissertation. January 2017. Major: Veterinary Medicine. Advisor: EUGENE NWAOKORIE. 1 computer file (PDF); xxix, 272 pages.

Related to




Series/Report Number

Funding information

Isbn identifier

Doi identifier

Previously Published Citation

Suggested citation

NWAOKORIE, EUGENE. (2017). Epidemiological Evaluation Of Uroliths In Selected Animals. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/194567.

Content distributed via the University Digital Conservancy may be subject to additional license and use restrictions applied by the depositor. By using these files, users agree to the Terms of Use. Materials in the UDC may contain content that is disturbing and/or harmful. For more information, please see our statement on harmful content in digital repositories.