Nobody takes better care of newborn kittens than their mothers.
However, not all kittens are fortunate enough to have their mother by their side. Many of them are orphans, ending up on the streets or in shelters.
This is where we step in to substitute all the mother cat does for her offspring. This includes keeping them warm, grooming them, protecting them from danger, and, of course, feeding them.
Bottle-feeding a kitten is the only way for it to get the necessary nutrients. If you’ve never had experience with this, you could think that this is just about getting a bottle and kitten formula.
However, there are some additional concerns here. To be more precise, there are certain side effects of bottle-feeding kittens.
Let’s look at them for you to be prepared for potential troubles. Also, we provide you with solutions for each of these seven side effects.
The initial issue you could encounter is your small kitten refusing to eat, which could lead to underfeeding and potentially even a fatal outcome.
There are a couple of possible explanations for this. The kitten may be too cold since it cannot regulate its body temperature. This can affect its desire to eat.
Also, the milk you’re giving to it may not be warm enough, making it unappealing to the kitten.
Furthermore, there’s also a chance that the kitten is unwell, which results in its unwillingness to eat or do anything else.
How To Solve?
It’s crucial you keep your small kitten warm all the time. Your body warmth can come in handy here – you should tuck the kitten against your skin under your clothes.
The other thing to bear in mind is to keep the kitten in a warm and isolated part of the house, without children and other pets around. You can also place the kitten on a heating pad under a heavy towel to prevent chances of burning.
It’s very important to keep the milk just warm enough to stimulate the kitten’s appetite. According to Maddie’s Fund Champions for Animal Welfare, the milk should be warmed up to 95-100 °F using a warm water bath. You should avoid warming the bottle up in the microwave.
If more than six hours have passed since the kitten’s last meal, and you suspect it may be sick, you need to arrange an emergency vet examination right away.
In case a kitten goes without any food for an entire day, it will become weak, malnourished, and will require veterinary care.
While some kittens could refuse the bottle, others will experience the opposite bottle-feeding side effect – overfeeding.
Young kittens need frequent eating and this will demand some sacrifice. One of them is that you shouldn’t leave your kitten alone overnight while you sleep without getting up to give it a bottle.
However, this will only last for a couple of weeks until the kitten starts eating solid foods. If you’re a novice cat parent, it could be challenging for you to determine the desirable amount and frequency of feeding your kitten.
You could think that your kitten needs more food, and it will look like it wants you to keep feeding it. This can lead to overfeeding which is as equally undesirable as underfeeding.
How To Solve?
Young kittens should eat every two to four hours. They should have about eight milliliters of kitten formula per ounce of body weight per day.
Revival Animal Health explains that it’s necessary to feed the kitten until the tummy starts to distend.
The kitten’s stomach should feel full but not stretched. This is a sign that your kitten has had enough food and that you should stop giving it a bottle to prevent overfeeding.
Colic is another potential side effect in kittens that are bottle-fed.
In simple words, this condition occurs when there’s a buildup of gas in a kitten, causing severe stomach pain.
Colic can also cause abdominal distension, weakness, and loss of appetite in young kittens. In most cases, colic happens due to a kitten eating formula that doesn’t suit it.
Also, it’s possible that you may not be feeding the kitten in the right way.
How To Solve?
In case you’re using a formula that your kitten isn’t accepting well, you should consult a veterinarian on the best replacement.
When you feed your kitten, ensure that you hold it upright on its sternum. It’s crucial not to position it on its back during nursing.
Another thing to do here is to help your kitten burp after feeding. This is the best way to prevent colic issues.
While a mother cat grooms its offspring to make them burp, you should thump your kitten with a finger while keeping its head up. This will help it get rid of the excess gas.
Some kittens eating formula could develop constipation problems. There are a couple of common causes for this gastrointestinal issue.
A young kitten could be dehydrated. It’s also possible that the kitten formula isn’t concentrated enough.
Furthermore, some kittens require stimulation to pee and poop.
How To Solve?
In case you notice your kitten isn’t pooping regularly, you should try adding 25% more water to its formula, until its stool appears and looks normal.
Once again, a kitten could need a replacement for its formula, since the one currently used could be causing constipation issues.
There’s also a possibility the kitten needs probiotics supplements and this is something that should be discussed with a veterinarian.
You can find more useful advice on this issue in our article on what to do if a 4-week-old kitten hasn’t pooped in two days?
Diarrhea is another side effect of bottle feeding in kittens.
This gastrointestinal issue can occur due to overfeeding. Also, it’s possible that an uncleaned bottle can cause diarrhea in a kitten.
Sour milk can also be a culprit of diarrhea. Moreover, kittens with diarrhea could be facing a parasite infection.
How To Solve?
PetMD explains how diarrhea can be a serious problem for young kittens because their bodies aren’t as well-equipped to handle this condition as adult cats. Kittens having diarrhea can quickly become malnourished and dehydrated.
Therefore, as soon as you notice diarrhea for the first time, you should try to help your kitten. Make sure you’re not overfeeding it, but that it still receives the necessary amount of food.
Clean the bottle with dish soap and warm water. Also, you should sterilize it in boiling water once every 24 to 48 hours.
If there is some milk left over, refrigerate it in a clean and closed container for no longer than 24 hours. In case the milk has been left out at room temperature for longer than one hour, and it was previously warmed up, throw it away.
Monitor your kitten closely to see whether its stool has become normal.
If necessary, reach out to a veterinarian. There is a chance that a kitten will need deworming.
6. Coughing And Labored Breathing
This side effect can potentially be life-threatening.
Some kittens could experience coughing and labored breathing due to inhalation of milk into the lungs.
This condition is known as aspiration pneumonia. According to Red Bank Veterinary Hospitals, newborn kittens can eat more quickly than they can swallow, resulting in aspiration of some of the milk into their lungs.
This is a severe condition and a common cause of death in bottle-fed kittens.
How To Solve?
As soon as you notice coughing and trouble breathing in a kitten, you should take it to a vet emergency room.
Aspiration pneumonia in kittens is a medical emergency. The veterinarian will administer antibiotics to combat infection and may provide oxygen therapy and breathing treatments. In severe cases, a kitten could even need ventilator support.
To avoid this scary scenario, you should always feed a kitten in the proper belly-down posture. The thing you should never do is squeeze formula forcefully into a kitten’s throat.
Every kitten is extremely vulnerable and sensitive during its first few weeks of life.
Keylla Helena Nobre Pacífico Pereira and her associates  point out that the neonatal period in felines is still a major challenge for breeders and veterinarians, which is associated with high rates of morbidity, ranging from 14% to 16%.
Bottle-fed kittens are even at higher risk, since they lack their mother’s protection and care. When you feed a kitten with formula, there is a chance that you could transmit any type of bacteria or viruses to it.
While this usually won’t cause serious consequences in adult felines, any kind of infection can be fatal for newborn kittens.
How To Solve?
Hygiene should be your number one priority during the period of feeding your kitten.
Wash your hands thoroughly before you start feeding your kitten. Take off the shoes you wear outside before entering the room where your kitten stays. Shoes can be a way for germs to cause harm to a young kitten.
Sterilize the bottle regularly and rinse it well after using soap. Also, the important thing here is to keep your kitten clean, too.
While a mother cat does a great job here with grooming its offspring, in this case, you’ll be the one replacing her role and keeping your kitten clean.
You can use a warm damp washcloth. Make sure there isn’t any feces or pee on your kitten’s body.
After the kitten is done eating, wipe down its face so that there isn’t any milk sticking to its fur.
Keeping yourself, your kitten, and its surroundings spotlessly clean is the best way to prevent infections.
Bottle-feeding a kitten isn’t the simplest experience you may encounter, especially if you’re a novice cat parent.
There are many things to keep in mind to ensure your kitten is well-fed and safe. After all, you’re replacing its mother and doing everything she would normally do to care for her offspring.
Side effects such as underfeeding and overfeeding are possible while bottle feeding a kitten. Here it’s crucial to provide a kitten with enough food and be sure that it’s gaining weight.
Gastrointestinal problems like diarrhea and constipation are also common with newborn kittens.
You need to make sure that your kitten is responding well to the formula and that the milk you give to it is always fresh.
Also, it’s very important to keep the kitten in an adequate position while feeding it. In some cases, like with a kitten coughing and having trouble breathing, it will even be necessary to ask for professional help.
Finally, an essential thing to do here is to keep hygiene at the highest level possible.
This isn’t an easy task and might sound a bit overwhelming for some of you. However, I guarantee you that it’s truly a special feeling seeing a vulnerable kitten thriving and becoming a strong and sturdy cat.
All the sacrifice, dedication, and lack of sleep for some nights will pay off!
 Pereira KHNP, Fuchs KDM, Corrêa JV, Chiacchio SB, Lourenço MLG. Neonatology: Topics on Puppies and Kittens Neonatal Management to Improve Neonatal Outcome. Animals (Basel). 2022 Dec 5;12(23):3426. DOI, Retrieved November 17, 2023.
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