Introduction
Cats throwing up after drinking milk is a common issue many cat owners face. There are several potential reasons why your cat may vomit after consuming milk, including lactose intolerance, milk allergy, high fat content in the milk, sudden diet change, overeating, and more. In this article, we’ll outline the main causes for cats throwing up after drinking milk and provide tips to prevent it from happening.
Lactose Intolerance
Lactose is a sugar found in milk and dairy products. As kittens, cats produce an enzyme called lactase that allows them to digest the lactose in their mother’s milk. However, as cats mature, most stop producing significant amounts of lactase and become lactose intolerant (source).
It’s estimated that over 50% of adult cats are lactose intolerant to some degree (source). When a lactose intolerant cat drinks regular cow’s milk, their body is unable to properly digest the lactose. This causes gastrointestinal upset, diarrhea, gas, bloating, and vomiting as the undigested lactose ferments in the intestines.
The severity of lactose intolerance can vary between individual cats. Some may experience mild symptoms while others can have more severe gastrointestinal distress after consuming milk. But the result is the same – the cat’s body simply cannot handle lactose after kittenhood.
Milk Allergy
A milk allergy in cats is caused by an overreaction of the immune system to the protein casein found in milk. This immune response triggers the release of histamine, which leads to symptoms like itching, hives, swelling, and gastrointestinal issues. The allergy can range from mild to severe. Some cats may only experience soft stools after drinking milk, while others can have life-threatening anaphylaxis.
A true milk allergy is different than lactose intolerance. With an allergy, even lactose-free milk causes issues since the offending protein is casein. A cat may be allergic to all forms of dairy including milk, cheese, yogurt, etc. According to WagWalking, some signs of a milk allergy in cats include:
– Vomiting
– Diarrhea
– Itchy skin, rashes, hives
– Paw chewing
– Swollen face
– Wheezing or coughing
– Collapse, trouble breathing
To manage a milk allergy, all dairy products should be avoided. There are milk replacers made for cats that do not contain casein. A veterinarian can help diagnose the allergy through methods like a skin or blood test. They may also prescribe medications like antihistamines to control symptoms. Keeping the cat away from all dairy products is key to prevent adverse reactions.
Fat Content
The high fat content of milk can also lead to vomiting in some cats. Cow’s milk typically contains around 3-4% fat, which is difficult for some cats to digest properly. The fat and lactose together create a very rich, fatty meal that can overwhelm the digestive system. Cats are obligate carnivores and their bodies are designed to digest a high-protein, low-carb diet. Consuming the fatty milk on top of their regular food can be too much for their stomachs to handle. This results in the milk being quickly expelled through vomiting. Some cats may even develop pancreatitis, which is inflammation of the pancreas, from consuming too much fat. To avoid vomiting and stomach upset, it’s best to avoid giving cats cow’s milk.
Source: https://www.purina.co.uk/articles/cats/feeding/guides/what-do-cats-drink
Sudden Diet Change
An abrupt change to a milk-based diet can shock the digestive system and lead to vomiting or diarrhea in cats. When transitioning to a new food, it is important to do so gradually over the course of 5-7 days. As noted in this source, mixing a small amount of the new food in with the previous food allows the digestive system time to adapt to the changes in nutrients and ingredients. According to this article, a sudden switch can disrupt the populations of beneficial bacteria in the gut, causing gastrointestinal distress until the body can rebalance.
If a cat begins vomiting after being given milk, it is likely because the milk is new in its diet and the digestive system has not had time to adjust. Starting with small amounts of milk mixed into their existing food can help avoid shocking the stomach. However, some cats may be inherently intolerant to milk due to lactose and switching their diet more slowly may not solve the issue.
Overeating
Drinking too much milk at once can lead to vomiting. Cats have a natural inclination to lap up milk quickly when given the opportunity. However, consuming milk too rapidly can overwhelm the digestive system and lead to vomiting.
The lactose and high fat content of milk is difficult for cats to digest. Drinking a large quantity at once exacerbates this issue. The stomach becomes overloaded and must eliminate the excess milk by vomiting before it can cause more severe gastrointestinal upset.
To prevent overeating of milk, give your cat only small amounts at a time. Provide milk in a shallow bowl rather than a deep one, so your cat cannot gulp down too much at once. Stick to 1-2 tablespoons of milk at a time, and wait at least an hour before offering more.
Cats will often overeat palatable human foods like milk when available. It is best to offer milk sparingly as an occasional treat. This will help prevent overconsumption leading to vomiting. Monitoring your cat and restricting intake is key to allowing milk without adverse effects.
Milk Alternatives
Since many cats are lactose intolerant, non-dairy milks may be better tolerated than regular cow’s milk. Some alternatives to try include:
- Lactose-free cat milk: Products like CatSip are made specifically for cats and contain less lactose.
- Goat’s milk: Goat’s milk contains 20-30% less lactose than cow’s milk, so some cats may tolerate it better. Introduce gradually.
- Almond milk: This plant-based milk is lactose-free. Make sure to choose an unsweetened version.
- Coconut milk: Coconut milk is also lactose-free and lower in fat and calories than cow’s milk.
- Soy milk: Opt for unsweetened soy milk, which does not contain lactose.
- Rice milk: Rice milk is another lactose-free, plant-based option to try.
When transitioning to a non-dairy milk, introduce it slowly mixed with water to allow your cat’s digestive system to adjust. Monitor for signs of intolerance like vomiting or diarrhea. Non-dairy milks can provide important hydration for cats without the gastrointestinal upset of regular cow’s milk.
Other Causes
There are some other potential medical causes for a cat vomiting after drinking milk, according to veterinarians from VCA Animal Hospitals (https://vcahospitals.com/know-your-pet/milk-intolerance-in-cats). These include:
- Inflammatory bowel disease – This chronic gastrointestinal condition can cause vomiting and diarrhea in cats.
- Food allergies or intolerances – Besides lactose, cats may have adverse reactions to other ingredients in milk like casein.
- Pancreatitis – Inflammation of the pancreas often leads to vomiting along with loss of appetite and lethargy.
- Feline infectious peritonitis (FIP) – This viral disease affects the gastrointestinal tract and can cause vomiting.
- Cancer – Gastrointestinal cancers like lymphoma may produce vomiting as a symptom.
A full diagnostic workup by a veterinarian is required to determine if any of these conditions could be the underlying cause of a cat vomiting after drinking milk. Treatment will depend on the specific diagnosis.
Prevention
To prevent your cat from getting sick after drinking milk, it’s best to avoid giving cows’ milk altogether. Here are some tips:
- Gradually transition your cat off milk by diluting it with water until they are no longer consuming it.
- Swap milk for more digestible milk alternatives like goat’s milk or kitten milk replacement formula.
- Stick to water or cat-safe liquids like bone broth or tuna juice instead of milk.
- Distract your cat from milk by offering enticing wet food, meat baby food, or treats.
- Keep milk and dairy products out of reach from counters and the fridge.
- If your cat begs for milk, try redirecting to playtime or brushing to shift their focus.
Consult your vet if you need help transitioning your lactose intolerant cat’s diet. With patience and the right milk substitutes, you can prevent unwanted vomiting or diarrhea episodes.
When to See the Vet
Vomiting can sometimes be normal for cats, but it’s important to monitor your cat and know when to seek veterinary care. You should take your cat to the vet if the vomiting persists beyond 24 hours, contains blood, or is accompanied by other concerning symptoms. According to Birchlake Animal Hospital, you should seek immediate veterinary care if your cat is vomiting and also lethargic, not eating or drinking, or has diarrhea. Prolonged vomiting can lead to dehydration and electrolyte imbalances, so it’s crucial to get veterinary treatment if the vomiting doesn’t stop. Petcoach also recommends seeing a vet if your cat vomits more than 2-3 times in one day. In most cases, acute vomiting after drinking milk will resolve on its own after the milk passes through your cat’s system. But recurrent or prolonged vomiting warrants an exam and treatment from your veterinarian to determine and address the underlying cause.