How to Help Runt Kitten Gain Weight?

Is one of your kittens different and unusual than other kittens?? Does it seem much smaller and thinner than their littermates??

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Are you worried about your cat’s health and growth? If that sounds like you, then you might have a runt kitten in your hands. These cats are born weaker and need extra care and attention. They often face many challenges to survive and thrive.

Therefore, helping runt cats gain weight is crucial for their overall well-being. Read on to learn what causes runt kittens to be underweight and how to help them thrive.

How can you identify a runt kitten?

First thing you have to do is identify whether your kitten is a runt or not. And for that, you have to look for some signs. 

What are the signs of a runt kitten?

It’s no secret that cats are very resilient animals. So, when they are born smaller and weaker than their siblings, we don’t see any obvious outward signs, especially in the first few days. Yet we can still notice this, but how?

There are some signs you should look out for, such as low birth weight, slow growth, and poor health. If you see these signs, you can almost be sure that your kitten is a runt. But just knowing that it is different is not enough. You need to differentiate between a runt and a healthy kitten. 

How can you differentiate between a runt and a healthy kitten?

Well, if we talk about healthy kittens, they are usually the average size and weight for their age and breed. They are energetic, playful, curious, and alert.

Moreover, they have a good appetite and can nurse well from their mother or a bottle. While talking about physique, a healthy kitten has a warm and pink skin tone, and a clean and shiny coat.

For runt of the litter cats, they are underweight than usual, have trouble nursing, breathing or staging warm. There are some ways to differentiate between a runt and a healthy kitten are:

  • Weigh them: A healthy kitten should gain about 10 grams per day in the first week of life, and about 15 grams per day in the second week. 
  • Measure them: A healthy kitten should grow about 1 inch per week in the first month of life.
  • Check them: A healthy kitten should have clear eyes, ears, nose, and mouth, a strong heartbeat and breathing rate. They will have a normal body temperature (around 100 °F or 37.78 °C).

If your little furball weight height and body condition doesn’t match with the above, then it’s a runt. 

What are the causes of poor weight gain in runt kittens?

Now we know which kitten is healthy and which one is a runt. Let’s see what causes a baby cat to gain poor weight. 

Are genetic factors involved?

You may be wondering if there are any inherited issues involved. Well, the answer is Genetic defects may cause the underdevelopment of runt kittens when they were born.

It’s not the only reason for their underweight. Some runts may have health issues like congenital defects or abnormalities that affect their usual growth and health. However, not all runts have genetic issues. 

What health issues or underlying conditions can affect weight gain?

  1. Fading kitten syndrome: This is a life-threatening condition that affects up to 30 percent of kittens. It is defined by a failure to thrive between the ages of birth and weaning. 
  1. Congenital defects: Congenital defects such as heart problem, cleft palate, hernia, or other malformation happen at birth. These flaws can impact their health. 
  1. Metabolic abnormalities: These abnormalities limit the body’s ability to use or produce energy, which influences the runt baby cat’s normal development and weight. 
  1. Intestinal parasites: Parasites like roundworms, coccidial, tapeworms, or hookworms may infest in the intestines and feed on the nutrients of the host. As a result, it can cause diarrhea, lethargy, blood loss, malnutrition, and stunted growth in your little furball. 
  1. Infections: As runt ones have weaker immune systems than others, they are more vulnerable to infections, which are caused by virus, fungi, or other parasites and resulting in other complications that can hinder weight gain.  
  1. Gastrointestinal disorders: Intestine inflammation can occur due to infections, bowel disease, food intolerance or colitis. These can cause diarrhea, dehydration, poor absorption of nutrients, and weight loss in runt cats.  

How does inadequate nutrition or feeding practices contribute?

Another reason for poor weight gain in runt cats is inadequate nutrition or feeding practices. For instance, insufficient milk supply from the mother cat due to large litter can contribute to poor weight gain.

Additionally, improper techniques like the feeding frequency, formula choice, transitioning to solid food, overfeeding, or underfeeding can disrupt their growth and lead to poor weight gain.

When should you consult a veterinarian and what will they examine?

Why is professional advice important?

Professional advice is critical because runt cats may have medical conditions or other behavioral issues that affect their pound gain and survival. An experienced veterinarian can diagnose and treat these problems, provide guidance on caring for them, monitor their growth and development, and recommend if they need any necessary intercessions or adjustments.

When should you schedule a veterinary visit?

Well, you should schedule a veterinary visit as soon as possible if you suspect you have a runt in the litter. Ideally, all kittens should be examined by a vet within the first week after birth, and regularly until they are fully vaccinated and spayed or neutered. Nevertheless, runt litter may need more frequent visits to check up on their overall progress. 

What diagnostic tests and assessments might be conducted?

A veterinarian may conduct various diagnostic tests and assessments to determine the cause and severity of your runt kitten’s condition. Such as a physical examination to check your kitty’s vital signs, body condition, and signs for infection, inflammations, or congenital defects. They will run some blood tests, urine or fecal tests to identify metabolic disorders or other diseases. Lastly they will do some x-rays, ultrasound, or MRI to diagnose heart problems, hernia or other malformations.

How can you create a suitable environment for a runt kitten?

What can you do to provide a warm and comfortable space?

Provide them with soft, clean, cozy bedding. You can also use a heating pad, a hot water bottle, or a snuggle safe to keep them warm. Make sure they are not too hot or accessible to move away if they are uncomfortable. Place their bed away from loud noises, bright lights, or other pets that may disturb them.

How can you ensure a stress-free environment?

Ensure a stress-free environment by providing them with nutritious food, water, litter boxes, toys, and scratching posts. Avoid any sudden changes in their routine or environment that may stress them. Use calming products such as pheromones, herbs, or music to help them relax.

How should you handle interactions with a runt kitten?

As these kittens are more timid or fearful than other pets, it’ll take more time and patience to trust you. Use soft voice and gentle touch when you approach them. Like other cats, you can also use treats, toys, or games to encourage them to play and interact with you, but with more diligence and carefulness. Gradually introduce them to other pets in the house (if you have).

[You can also track them with a microchip to make sure they are supervised and safe. How to do it? One click will tell you the answer]  

What are the best feeding strategies for a runt kitten?

If the runt kitten won’t nurse from its mother or is rejected by her, it will need a kitten formula to provide it with the necessary nutrients. 

How do you choose the right kitten formula?

Choose a high quality kitten formula that matches their nutritional needs and age, contains protein, fat, carbohydrates, vitamins, and minerals. Avoid cow’s milk, goat’s milk or human baby formula. 

What techniques are recommended for bottle feeding?

  • Warm the formula to body temperature (about 100 °F) by placing the bottle in a bowl of warm water. (Do not microwave!)
  • Sterilize the bottle and nipple before each use by boiling them in water for 10 minutes. 
  • Hold the kitten upright, gently squeeze the bottle to release a drop of milk, and let the kitten suckle.
  • If the kitten does not suckle, try rubbing its throat or stroking its back. Do not force or overfeed. 

[watch this video Runt of the Litter, learn how to care for a Malnourished Kitten]

How can you establish a feeding schedule?

Feed the kitten every 2 to 4 hours, depending on their growth and weight. Gradually increase the amount and decrease the frequency as they develop. Consult a vet for guidance on how much and how often to feed.

What should you monitor regarding the kitten’s intake?

Monitor the kitten’s intake and growth. Weigh them daily and keep track of their development. Check for signs of dehydration, constipation, diarrhea, or vomiting. Seek veterinary help if you notice any concern.

Are there nutritional supplements that can help a runt kitten?

Should you consult a veterinarian for supplements?

Well, yes! They will advise you on what type of supplements are suitable for them, how much and frequently to give them, and what are the possible side effects or interactions.

What are some appropriate supplements for runt kittens?

There’s no specific supplement for runt cats, but there are some types that may help your furball. Apply those obviously after having consultation with a veterinarian. Such as-

  • Kitten formula (Powdered by PetAg is recommended)
  • Taurine (amino acid)
  • High-calorie gel
  • Immunity booster (oral spray)
  • Multivitamins and minerals supplements.  

How should you determine the proper dosage and administration?

Basically it depends on several factors like supplement type, age, weight, kitten condition and the veterinarian’s recommendation. Here are some guidelines-

  • Kitten formula should be fed about 8 ml (1/4 oz) of formula per ounce of body weight per day.
  • High-calorie gel, should be fed 1/4 teaspoon of gel per 10 oz of body weight per day.
  • For Taurine, it’s about 250 mg per day. You can add this supplement to formula or other food. 
  • Vitamin/mineral supplement, can be fed about 1/4 tablet or capsule per day. This can be crushed and mixed with the formula or food before feeding.

All of these supplements should be divided into several feedings throughout the day and night, depending on the kitten’s age and pounds.

How can you increase appetite and encourage eating in a runt kitten?

What are effective ways to encourage play and exercise?

Like other cats, you can use toys, climbing frames, or laser pointers to entice your runt kitten to chase, pounce, and explore. Gently massage their body to improve blood circulation and relax its muscles. It will make them feel more comfortable around you, and strengthen the bond.

What types of enticing and palatable foods can you offer?

Something like a high in quality, calorie, protein diet that meets its nutritional needs. You can choose wet food, dry food, or a combination of both, tuna juice, chicken broth, or baby food (without onion and garlic).

Are there specific hand feeding techniques you can use?

If your runt kitten is unable to suckle from its mother or a bottle, you may need to hand feed it using a syringe, dropper, spoon or a soft tube (such as a catheter).

How do you track the progress of a runt kitten?

How often should you weigh and record the kitten’s weight?

The ideal amount of day to weigh and record the kitten’s pound is daily (at the same time each day). Compare with other littermates and normal growth charts.

You can also use a digital kitchen scale or a baby scale for measurement. Additionally, assess their body condition(e.g., ribs, waist, and abdomen) score by using a scale from 1 to 9, where 1 is very thin and 9 is very obese.

**Expecting gaining weight is at least 10 grams per day in the first week, and at least 100 grams per week in the first six months. 

**A healthy kitten should have a body condition score of 4 or 5.

What changes in behavior and appearance should you observe?

Some changes you should look for are their activity level like are they playful or lethargic, do they have good appetite or bad, are they well hydrated, do they breathe normally or labored, are their body temperature normal or under. Moreover, they should not have any infection, discharge or inflammation in eyes, ears, mouth, coats, or skin.

How can you note milestones and improvements?

You can take note by keeping a chart or journal. Record your felines every day’s weight, body condition, behavior, feeding schedule, appearance, medication schedule, veterinary visits, vaccinations, other treatments and procedures. You can also take photos and videos of their development stage and share it with your vet for feedback. 

What are the potential challenges and how can you solve them?

How do you deal with feeding difficulties?

Compared to other pets, runts often face feeding problems. For example, if they have trouble suckling from their mother or bottle, use alternatives like syringe or spoon. If they are not eating or hungry, rub some corn syrup on gums, then try again. Feed them in small amounts throughout the day. 

How can you address digestive issues?

To address digestive issues, you may need to change the formula or food type and amount. Add palatable foods, make it more moist, soft, and flavorful to prevent dehydration and constipation. Give them some probiotics, prebiotics, enzymes, or supplements to help balance its gut flora and improve its digestion (must be vet recommended). 

When should you seek veterinary guidance for complications?

If you notice them coughing, or labored breathing due to inhalation of milk or food into lungs, not taking the bottle for more than 6 hours, difficulty eating or swallowing, you should seek a vet’s guidance as soon as possible.

What additional care and support should you provide for a runt kitten?

How important is socialization and companionship?

Socialization and companionship are highly significant for development and well-being, whether it’s a runt kitten or other healthy cats. It’ll help the runt of the litters to learn social skills, cope up with stress, and thrive. 

What are the proper grooming and hygiene practices?

Regular grooming your malnourished cat with a soft brush or comb, trimming or clipping the claws carefully, cleaning their body, face gently with a wet cloth or cotton ball, bathing them occasionally with mild pet-shampoo or soap. Dry them thoroughly with a towel or dryer, wrap them with a blanket. Avoid frequent bathing, using harsh products. 

What vaccinations and preventive healthcare measures are necessary?

Make sure to vaccinate your runt cat according to your veterinarian’s recommendations. Some vaccination for common diseases such as feline panleukopenia (distemper, feline herpesvirus (rhinotracheitis), feline calicivirus (upper respiratory infection), feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), rabies, etc. 

Deworming to get rid of parasitic infections. Spay or neuter them when they are around 6 months of age to prevent unwanted pregnancies, reduce behavioral problems, and lower the risk of reproductive cancers.


It’s a challenging task to help a runt kitten gain weight. But if you follow our guidance, tips, hopefully you can give your cat a better comfortable and healthy life. 

If you have any questions or opinions, share them in the comment section. W’d love to hear from you. 

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