Background
Between 2006 and 2014, 10 cases of urolithiasis in yaks with calcium carbonate uroliths were confirmed in Switzerland, and at the same time, a sixfold calcium overhang in roughage in an affected farm was evident. The
Conclusions
The question of whether urolithiasis in yaks in alpine Switzerland poses a husbandry risk can be answered affirmatively. Calcium-rich forages play a crucial role in this multifactorial process.
Methods
Blood samples from 99 animals from 10 farms were examined (n = 6 problem farms; n = 4 control farms). Several metabolites were analyzed in the blood and urine. In addition, roughage, soil, and water samples were analyzed. The farms were distributed within different regions of Switzerland.
Results
This study revealed different Ca:P ratios, from 1.56 to 7.74:1, in the forages and mild hypercalcemia in the animals of the problem farms. In a univariate analysis of the problem versus control farms, about 20 other significant factors emerged. Multivariate analysis showed that altitude, CP (crude protein), P, Mg, NDF, and ADF in the diet are important factors. Based on analysis of the pedigree, there was no evidence of an obvious genetic background of urolithiasis. Limitations: A limitation of this study is the small number of yaks in Switzerland. Conclusions: The question of whether urolithiasis in yaks in alpine Switzerland poses a husbandry risk can be answered affirmatively. Calcium-rich forages play a crucial role in this multifactorial process.