Iodine is essential for your rabbit's thyroid gland to produce the hormones T3 and T4, which regulate metabolism, body temperature, growth, and overall energy levels. Without adequate iodine, the thyroid cannot function properly, leading to a cascade of metabolic slowdowns. Rabbits need only trace amounts, and most quality pellets include supplemental iodine. Some leafy greens — particularly those from the brassica family like kale and broccoli — actually contain goitrogens that can interfere with iodine uptake, which is one reason to rotate cruciferous vegetables rather than feeding them daily.
A small sprig of watercress (about 10g) provides roughly 1 to 2mcg of iodine — barely visible to the naked eye in pure form. Your adult rabbit needs approximately 0.2 to 0.5mg of iodine per kilogram of diet. Quality rabbit pellets include supplemental iodine, and a varied diet of greens contributes trace amounts. No additional supplementation is needed.
0.0% of daily nutrient intake
Iodine makes up 0.0% of your domestic rabbit's total daily nutritional requirements by weight. That's a tiny amount — but it matters.
Goiter (visible swelling of the thyroid gland in the neck area), lethargy, weight gain despite normal eating, poor coat quality, cold intolerance, and reproductive problems in breeding rabbits. Severe deficiency can cause stunted growth in young kits.
Excess iodine can paradoxically suppress thyroid function, causing similar symptoms to deficiency. This is very unlikely from food sources and would only occur with inappropriate supplementation.
| Life Stage | Size | Min | Max | Unit | Notes |
|---|---|---|---|---|---|
| Adult | — | 0.02 | 0.05 | mg | About 0.2-0.5mg per kilogram of diet. Supplied by pellets and varied greens. |
| Pregnant / Nursing | — | 0.03 | 0.07 | mg | Slightly increased during pregnancy and lactation for fetal thyroid development. |
Source: NRC 1977, general veterinary consensus
Goitrogens in cruciferous vegetables (kale, broccoli, cauliflower, bok choy) interfere with the thyroid gland's ability to absorb iodine and produce thyroid hormones. When goitrogen-rich foods are fed consistently as the dominant green, they can effectively reduce the iodine available to the thyroid, potentially suppressing its function over time.
What this means: Rotate cruciferous vegetables with non-cruciferous greens so your rabbit gets the nutritional benefits of kale and broccoli without sustained goitrogen exposure. If your rabbit shows signs of thyroid issues (lethargy, weight gain, poor coat), discuss goitrogen intake with your vet.
