Many of the dogs I work with have urine pH that’s too high or too low. In most cases, the urine has crystals in it and in some, the dog develops urinary tract stones. I wrote a post about the different types of stones and their formation here, and received a number of questions from readers that I want to address now. The most common was about the great swing in urine pH over the course of the day. Say you check first thing in the morning and find that pH is 5.0, check 2 hours after a meal and find it’s 9.0. Which one should you go by when you’re trying to get the pH at a nice and steady 6.5 which is an ideal number? There’s a measurable alkaline tide that you should consider. It goes like this:
While the stomach is always producing some acid to keep the pH in the stomach around 2-ish, after a meal there is a flood of hydrochloric acid produced by the parietal cells. In the chemical reaction they use to make that acid, a flood of sodium bicarbonate (base) is produced.
That base or alkali has to go somewhere and it goes out into the blood stream.Well, the bloodstream has to stay around pH 7.2 for health and safety, so that extra alkali gets taken out of the blood by the kidneys and goes into the urine. So right after a meal, you’ll get a rise in pH in the bloodstream that’s pretty temporary and then a rise in urine pH soon after. The urine pH increase lasts longer and about 2 – 4 hours after a meal is perfect timing for that.
While fluctuations in pH in urine are normal over a day, the average pH of the urine over 24 hours is more important, and so is keeping the pet well hydrated. Sometimes, 24 hour urine collections are done for dogs or cats to find out the average pH over a day (kind of a pain to do) along with average specific gravity for hydration. It’s important to not react to a single pH reading in a 24-cycle.
Chances are that the urine pH first thing in the morning (before a meal) is the predominant reading for that dog, but as explained above it’s not as simple as that, so I encourage my clients to check throughout the day to get an average.