waterlilly0212 wrote:
I tried switching his greens from swiss chard to endive, but that didn't seem to make a difference!
First off, how many greens does he get? I'm a firm believer that the key to a good bunny diet is variety. My guys will usually get a half dozen different veggies in their salads (or more).The minimum isthee kinds per setting, including one that's not a green -- red cabbage, pepper, carrot, raddiccio (sp?), cauliflower. (Red lettuce doesn'to count).
I also keepan eye open tooverloading on any one group -- ie: not kale, broccoli, cauliflower, Brussels sprouts and cabbage at the same meal, they all have similar properties. Just like I won't feed high calcium collard greens, radish tops, carrot tops, dandelion leaves and parsley in one setting, but I don't micromanage the counts.
The calcium issue is a misunderstood quagmire.I don't think there's much of an argument anymore that the calcium content in vegetables when it comes to a rabbit diet rarely matters.Given the water content, the benefits will far outweigh the negatives with urinary issues. However, if a certain vegetable consistently produced while urine, then best to cut it out.
But calcium overload (and absorbency) is much more of an issue in rabbit pellets. Alfalfa pellets have a high calcium content and if a rabbit is consistently putting out white urine,they should be weaned off of them.
Check out these Library listings...
Urinary Problems (especially this one)
Vegetables
Feeding Your Rabbit
And here's a good article about the calcium issue by Susan Brown and Laura Atkins.
http://www.carrotcafe.com/n/calcium.html
Here's an excerpt:
II. Why calcium is an issue in rabbits
Rabbits are different in that they appear to absorb most of the free calcium in their diet. The calcium level in their blood is not regulated well, in fact blood levels increase in proportion to the calcium in their diet. They also primarily excrete calcium through the urine, unlike other mammals which primarily excrete calcium through the bile and ultimately through the feces. Rabbits also excrete a highly alkaline (basic) urine which, combined with a high calcium level, can form calcium carbonate crystals ("bladder sludge") or stones.
Bladder sludge and stones are the reason many veterinarians and rabbit people believe that calcium should be limited in rabbits. In some cases, they are probably correct. The form of calcium in rabbit pellets is highly absorbable, as is the calcium in alfalfa. This is primarily free calcium and the bunny intestine acts like a sponge and sucks it all in. Other forms of calcium, such as calcium oxalate, are not as absorbable (in some cases unabsorbable).
So, how much calcium is absorbed is dependent on what kind of calcium is in the diet as well as how much is present.
III. Why calcium is not an issue in rabbits
In terms of what we routinely feed bunnies, that is: hay, pellets, and vegetables, not all are created equal in calcium amount and type. Pellets contain calcium from alfalfa hay and calcium from sources like limestone. This type of calcium is in a very absorbable form and is something that is a good idea to watch. But, there are other reasons to limit pellets, so we assume there is not an overwhelming amount of calcium in them. For a bunny with problems, feeding a low calcium (typically timothy based) pellet is not a bad idea.
Alfalfa hay contains a high level of potassium as well as calcium. One of the texts I have suggests that the high level of potassium in alfalfa hay may contribute the formation to sludge or urine crystals. Certainly there is some evidence that the other minerals, such as potassium, magnesium, phosphate and even sodium, play a role in sludge formation in rabbits.
That leaves vegetables, and their calcium content. For the majority of vegetables, water levels are between 80 and 95% of the total weight of the plant. Many times when calcium levels are being reported, they are reported as a percentage of *dry weight*, which does not take into account the weight of water. So the actual amount of calcium being fed may be much less when you look at what you're actually feeding, not the dry weight of the food. Many vegetables that have significant calcium levels also have significant oxalate levels. Calcium bound to oxalate (called, oddly enough, calcium oxalate) is not readily absorbable by the rabbit. Any calcium that is not absorbed cannot contribute to sludge.
Needless to say, I don't pay attention to calcium content in veggies. What I do try and do is rotate veggies frequently to give the bunnies a balanced diet. I do have a list of the calcium content of selected vegetables. If you are interested in oxalate levels of various vegetables I have a chart of that, too. To round out the group, there is also a list of calcium content of selected hays. In general, feeding a "high calcium" veggie is not going to harm your bunny. As always, you want to monitor bunny's output. If feeding one veggie or another consistently results in sandy looking urine, then you may want to decrease the amount you feed, or remove it from their diet entirely.