How to Reduce Calcium in Your Rabbit’s Diet

Does your rabbit have trouble with too much calcium? Excess calcium can wreak havoc on a rabbit’s health. It puts them at risk for painful bladder stones, kidney issues, and even heart complications! The solution lies in a proper low calcium diet. Through careful selection of hay, pellets, veggies and more, you can create the perfect balance to keep your bunny healthy. This guide will walk you through everything you need to know about reducing calcium in your rabbit’s diet. You’ll learn about how rabbits process calcium, what causes unhealthy excess, and most importantly, how to provide a nutritious low calcium diet. Get ready to hop into action for your bunny’s wellbeing!

Low Calcium Diet for Rabbits

A proper diet is essential for the health and wellbeing of pet rabbits. While rabbits require adequate amounts of calcium for strong bones and teeth, excessive calcium can lead to serious health issues. Creating a balanced, low calcium diet for rabbits involves carefully selecting ingredients and monitoring calcium levels.

A low calcium rabbit diet aims to provide all the nutrients a rabbit needs while limiting high calcium foods. The goal is a calcium level of around 0.5% to 1% of their diet. This prevents excessive calcium intake which can cause bladder sludge, kidney stones, and other problems. Monitoring urinary health and adjusting the diet as needed is important.

When switching a rabbit to a low calcium diet, changes should be made slowly over 1-2 weeks. This allows their digestive system to adjust and avoids causing further issues. Patience is key, as diet changes may not show results immediately. With the right low calcium diet, rabbits can thrive and avoid complications related to excessive calcium.

How Do Rabbits Process Calcium?

Rabbits have a unique physiology when it comes to processing calcium in their diet. Here's an overview of how calcium metabolism works in rabbits:

  • Absorption – Rabbits absorb calcium efficiently, up to 60% of what they ingest. This occurs primarily in the small intestine.

  • Excretion – Unlike many mammals, rabbits cannot efficiently excrete excess calcium through their urine. Their kidneys resorb over 99% of calcium filtered through.

  • Storage – Rabbits store some calcium phosphate complexes in their skeleton. However, they lack a parathyroid hormone feedback loop to regulate bone calcium reserves.

  • Digestion – Rabbits produce calcium carbonate to buffer and facilitate digestion of plant matter in their hindgut. This provides a constant supply of calcium.

  • Reproduction – Female rabbits mobilize calcium from bones to help meet the high demands of pregnancy and lactation. After weaning, excess calcium can build up.

  • Growth – Young rabbits require calcium for skeletal growth and development. But as they reach maturity, calcium needs decrease.

In summary, rabbits evolved efficient calcium absorption without the ability to excrete surpluses. This leaves them prone to excessive calcium accumulation, especially when fed inappropriate diets high in calcium. Monitoring intake levels is important.

What Causes High Calcium in Rabbits?

There are several potential causes for high calcium levels, also called hypercalcemia, in pet rabbits:

  • Diet – Consuming too much calcium through food and treats is the most common cause. High calcium veggies, fruits, pellets, and hay may create excess.

  • Age – Mature, inactive rabbits require less calcium than young, growing rabbits. But they may continue eating calcium-rich diets.

  • Gender – Unspayed female rabbits can develop hypercalcemia after giving birth due to mobilizing and retaining calcium for milk production.

  • Kidney disease – Impaired kidney function reduces the excretion of excess calcium from the bloodstream. This allows build up over time.

  • Parathyroid disease – Tumors or dysfunction of the parathyroid glands can cause excess parathyroid hormone and calcium absorption.

  • Vitamin D excess – Too much vitamin D increases calcium absorption in the digestive tract leading to elevated blood calcium levels.

  • Cancer – Some cancers, like lymphoma, cause bones to leach out calcium increasing blood calcium.

  • Medications – Certain diuretics and lithium therapy can affect calcium homeostasis and lead to hypercalcemia.

Identifying and addressing the underlying cause is key to treating and preventing recurring high calcium levels in rabbits. A vet should diagnose the cause.

How Much Calcium Should Rabbits Have?

The recommended calcium levels for healthy pet rabbits are:

  • Kitten through 6 months old – 1.0% to 1.4% of diet

  • 6 months to 1 year old – 0.8% to 1.2% of diet

  • Adult rabbits over 1 year old – 0.5% to 0.8% of diet

Higher calcium needs in young rabbits support skeletal growth and development. But as rabbits mature, excess calcium can accumulate and cause health issues.

Adult rabbits, especially females over 2 years old, are at higher risk for hypercalcemia and associated urinary tract complications. Limiting dietary calcium to 0.5-0.8% is ideal for preventing excess intake.

Analyzing hay or having your vet assess blood calcium levels can help monitor the dietary calcium rabbits are receiving. Adjusting dietary calcium down is safer than providing excess amounts.

Reducing Calcium in a Rabbit's Diet

Here are some tips for reducing total calcium levels in a pet rabbit's diet:

  • Gradually transition to a timothy or oat hay rather than alfalfa hay, which is very high in calcium.

  • Limit calcium-rich vegetables like broccoli, kale, and spinach to occasional small servings.

  • Avoid calcium-fortified commercial treats and select grains/seeds treats instead.

  • Use a grass hay-based pellet formula with precise calcium levels around 0.5% to 0.8% total calcium.

  • Substitute lower calcium vegetables like cucumbers, peppers, carrots, and romaine lettuce for calcium-rich greens.

  • Check any vitamin supplements to ensure calcium levels are not excessive.

  • Have clean, fresh water always available to encourage drinking and urinary flow.

  • Monitor urine pH and watch for signs of sludge or stones, adjusting diet as needed.

  • Offer a variety of low calcium vegetables to ensure balanced nutrition.

  • Frequently measure and weigh food to feed proper portions and limit excess intake.

With a balanced, low calcium diet rabbits can get all the nutrients they need without the risks of excessive calcium. Always consult an exotic vet on ideal calcium levels for a rabbit's age, size, and health status. Monitoring and making adjustments takes patience but is worth it for their wellbeing.

Grass and Hay

Grass hay should make up the bulk of a pet rabbit's diet. But the calcium content varies significantly by source. Here are some tips for reducing calcium from grass hay:

  • Choose timothy, brome, Bermuda, or oat hays which are lower in calcium than legume hays like alfalfa.

  • Select a younger, less mature hay for lower calcium levels. Mature hays have higher fiber but more calcium.

  • Test hay calcium levels and aim for a percentage around 0.3% to 0.4% for adults.

  • Limit alfalfa hay to an occasional treat for young, growing rabbits. Adults should avoid it.

  • Rotate through different grass hays for variety and to average out differing calcium levels.

  • Soak hay thoroughly in water, then completely dry before feeding. This can leach some excess calcium.

  • Feed grass hay in moderation. Overeating, even low calcium hay, adds up in their diet.

  • Stemmy, seedy hay parts tend to be higher in calcium than leafy portions.

With attention to grass hay sources, you can identify and provide lower calcium hays suitable for an adult rabbit's diet. Consult your vet to help analyze options and calcium levels.

Dry Food

Dry food pellets designed for rabbits can be a convenient way to ensure balanced nutrition. But pellets vary widely in calcium content. Here are some tips for low calcium pellet diets:

  • Select an adult formula pellet with controlled calcium around 0.5% to 0.8%. Avoid alfalfa-based pellets.

  • Confirm calcium levels listed on the label or by contacting the manufacturer. Do not assume levels.

  • Feed a limited amount of pellets. 1/4 to 1/2 cup per day is plenty for an average sized adult rabbit.

  • Split the daily portions into at least 2 feedings. This prevents gorging.

  • Use plain, unfortified pellets without added seeds, fruits, nuts or vitamin mixes which add calcium.

  • Switch pellets slowly by mixing ratios over 1-2 weeks to help their digestive system adapt.

  • For young rabbits, choose age-appropriate pellets with proper calcium for growth. Adjust at 6-12 months old.

With a measured amount of an appropriate low calcium adult pellet formula, rabbits can get balanced nutrition without excess. Pellets should be just one component of a varied rabbit diet.

Low Calcium Vegetables and Plants

In addition to grass hay and limited pellets, many vegetables and plants can round out a low calcium rabbit diet. Focus on low and moderate calcium options:

Low Calcium Vegetables:

  • Carrots
  • Cucumbers
  • Bell Peppers
  • Radishes
  • Lettuce (romaine, not iceberg)
  • Tomatoes

Moderate Calcium Vegetables:

  • Cabbage
  • Cauliflower
  • Celery
  • Asparagus
  • Bean sprouts and pods
  • Brussel sprouts
  • Eggplant

Avoid or limit high calcium veggies like broccoli, spinach, kale, okra, mustard greens and swiss chard. Introduce new veggies slowly. Rotate through different moderate and low calcium vegetables for variety. Baby-sized portions help prevent overeating.

Water Consumption

Encouraging rabbits to drink more water can help flush excess calcium from their systems before it builds up. Try these tips:

  • Provide fresh, clean water daily in bowls or bottles. Refill when low.

  • Offer water in multiple bowls around living areas to promote drinking.

  • Position bowls away from food to avoid food contamination and increased intake.

  • Provide bowls large enough so ears don't get wet when drinking.

  • Flavor water lightly with healthy herbs or juice to entice drinking.

  • Let rabbits drink while exercising; intake increases with activity.

  • Adjust diets if urination decreases indicating less hydration.

  • Increase vegetable content and decrease dry hay temporarily to increase moisture intake.

  • Consult a vet about diuretic medication if dehydration persists.

Promoting water consumption in natural, healthy ways helps optimize urinary function and flushing of excess calcium in rabbits prone to accumulation. This supports a low calcium diet.


Creating a properly balanced low calcium diet for rabbits involves carefully selecting ingredients, portion control, and monitoring health. Adult rabbits in particular require controlled calcium around 0.5-0.8% of intake to prevent excess accumulation and associated health risks. Timothy hay, measured grass-based pellets, and low calcium vegetables can meet nutritional needs without going over. Working with an exotic vet, testing food calcium levels, assessing health frequently, and making gradual adjustments helps ensure rabbits thrive on a low calcium diet optimized for their needs. Proper nutrition is fundamental to a rabbit's health and happiness.


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