Why do cats get calcium deficiency?
The main reasons for calcium deficiency in cats are long-term insufficient nutrient intake and a diet high in liver. A healthy cat's calcium-to-phosphorus ratio should be 1:1. High-quality cat food is formulated according to this daily requirement. Fresh liver, however, has a calcium-to-phosphorus ratio of 1:36, so cats that regularly consume liver are prone to calcium deficiency.
I. Symptoms
Weakened stomach function, loss of appetite, pica, weight loss, acrophobia, slow movements, and lethargy can eventually lead to rickets and even paralysis.
II. Calcium and phosphorus deficiency
Loss of appetite, weakened stomach function, decreased activity level; pica, weight loss; acrophobia, slow movement; rickets in kittens; osteomalacia in adult cats.
III. Excessive
This can lead to slow growth, metabolic disorders, lameness, or long bone fractures.
Is it important to supplement calcium for cats?
Calcium is an essential nutrient for cats. Calcium is constantly lost from a cat's body, so continuous supplementation is necessary to maintain balance. Only when the amount of calcium supplemented exceeds the amount lost can a cat develop normally. 
There are several questions about giving calcium supplements to cats.
First, cats need calcium supplements throughout their entire growth process;
Secondly, kittenhood is a crucial period for a kitten's growth, and extra attention needs to be paid to calcium supplementation.
Third, older cats lose nutrients more quickly, so calcium supplementation is especially important;
Fourth, cats that are confirmed to be calcium deficient need more scientific calcium supplementation.
Under normal circumstances, a scientific diet should meet the calcium requirements for a cat's growth. However, due to various factors, cats are still prone to calcium deficiency. (For example, food lacking calcium, or poor calcium absorption, can all lead to calcium deficiency in cats). Therefore, special attention needs to be paid to calcium supplementation for cats.
If possible, it's best to have your cat checked regularly to see if they are calcium deficient. If it's mildly calcium deficient, you can improve their diet by providing calcium-rich foods and supplementing with calcium supplements. If the cat is severely calcium deficient, then you'll need to take them to the vet to develop a calcium supplementation plan, which may involve injections and supplements.
When supplementing your cat with calcium, it's important to also ensure they get adequate vitamins and other nutrients. Taking your cat out for some sunbathing is also beneficial, as the ultraviolet rays in sunlight can better promote the absorption of calcium, thus achieving the desired calcium supplementation. 
How to supplement calcium for cats?
Severe calcium deficiency in cats is a very serious problem. If the cat's calcium deficiency is caused by a long-term diet of liver, the first step is to stop feeding it liver and switch to high-quality cat food or a nutritionally complete diet. The second step is to supplement the cat with calcium.
Supplementary methods
1. Fish meal, meat and bone meal, and other animal-based foods containing bones (do not feed bones directly).
2. Replenish minerals
3. Get plenty of sunshine.
4. Breeding cats can be prevented or treated by injecting vitamin D and calcium supplements or by taking cod liver oil orally.
I hope every parent will take responsibility for their child and raise their cat scientifically. I hope all cats stay healthy.
