Final answer:
Ammonium biurate crystals, while normal in pets like horses, dogs, and cats, can indicate urolithiasis, the formation of urinary stones. Adjusting food choices to reduce nitrogenous bases can help prevent such conditions.
Step-by-step explanation:
The presence of ammonium biurate crystals in animals is normal, but they can also indicate the condition known as urolithiasis, which is the correct answer to the student's question. Urolithiasis refers to the formation of urinary stones, or uroliths, in the urinary tract. Ammonium biurate crystals may form when there is an excess of uric acid, which could be due to a metabolic disorder or dehydration. Struvite stones, a different type of urinary stone, are often associated with urinary tract infections and are composed of magnesium, ammonium, and phosphate.
In terms of preventing conditions like urolithiasis or gout, which is another issue related to excess uric acid, it's advised to avoid food choices that increase the amount of nitrogenous bases in the diet. This includes substances such as tea, coffee, and chocolate, which contain purine-like compounds known as xanthines.