The impact of nutrition on the development of urolithiasis in captive giraffes and meat goats

Obstructive urolithiasis is a documented problem in domestic ruminants, such as the meat goat, and also in captive giraffe. A survey of the health history, feeding practices, and dietary contents in captive giraffes in North America was conducted to examine the possible connection between diet and the development of urolithiasis. Samples of urine, serum and feed were collected and analyzed for basic panels and mineral content. There appeared to be a positive correlation between diet and physiologic phosphorus levels in giraffe. This may not have been related to the ingredients of the diet but rather to the ratio of concentrate to hay eaten and the nutrient composition of the concentrate. We hypothesized that high phosphorus content in the diet and a high level of concentrate feeding would increase indicators of urolith formations including crystal formation and high urine mineral content. We followed up with a metabolic trial in meat goats, testing 2 different complete pelleted feeds and 2 complete pelleted feed to hay ratios in a 2 by 2 factorial randomized complete block design. The intent of this study was to look at the impact of type of diet (ADF-16 or Wild Herbivore complete pelleted feed) and complete pelleted feed to hay ratios (20 or 80 % hay) on the development of urolithiasis in meat goats, in the context of captive giraffe feeding practices. The four treatments had a range of fiber content and differed in mineral content, particularly Ca to P ratio and levels of P. We also measured the number of crystals in the fresh urine, as these may be considered precursors to urolith formation. The ADF-16 diet where hay was 20% of the diet had the lowest levels of fiber, lowest Ca to P ratio, and highest level of phosphorus compared to the other 3 diet treatments. From our results, it can be concluded that feeding the ADF-16 diet where hay is 20% of the diet, produced a trend of high urinary P, high serum P and a tendency for a high crystal count in the urine over the four week experimental period. These can be considered strong risk factors for the development of phosphatic uroliths. As one third of the zoos which responded to the survey fed a majority of their diets as ADF-16, this conclusion warrants further investigation.

Publish DateMarch 9, 2020
Last UpdatedJanuary 31, 2021
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