According to some surveys, between 40-70% of owners or trainers use cheese as a treat/reward. However, cheese is made from milk and contains lactose (“milk sugar”). In puppies, the enzyme lactase, which breaks down lactose into glucose and galactose, is produced by the lining of the intestines. However, by the age of around 3 months, the ability to digest lactose has more or less disappeared.
How common is lactose intolerance in dogs, and what causes it?
Perhaps surprisingly, a number of studies have indicated that 70-80% of adult dogs are lactose intolerant. The intolerance is not caused by the lactose itself directly in the gut, but due to the fact that the lactose passes undigested into the large intestine, where bacteria such as Bifidobacterium or Clostridium ferment the lactose, producing short-chain fatty acids, hydrogen gas (H₂), methane (CH₄) and CO₂. Gas buildup leads to bloating, cramps and flatulence and undigested sugars also draw water into the colon, causing diarrhoea. Fermentation of the lactose by bacteria also lowers gut pH (makes it more acidic) and irritates the intestinal lining. Vomiting or nausea can occur in severe cases, and the symptoms can appear within 30 minutes to 2 hours of ingestion. Milk and yoghurt also carry the same risk.
How much cheese can cause a problem?
In some dogs, as little as 1g of lactose may be enough to produce symptoms. And some cheeses are higher in lactose than others. The table below lists cheeses to avoid due to higher lactose content. The best options to avoid upsetting your dog’s hindgut are Parmesan or aged cheddar!
| g lactose/100g cheese | |
| Ricotta | 3-5 |
| Mascarpone | 2-4 |
| Cottage Cheese | 2-3 |
| Cream Cheese | 2-3 |
| Mozarella | 1-2 |
| Feta | 1-2 |
| Mild cheddar | 0.5-1.0 |
| Parmesan | 0-0.1 |
| Aged cheddar | <0.1 |
Are some breeds more or less sensitive to lactose?
LOWER RISK – Labrador Retriever, Australian Shepherd, Border Collie, Golden Retriever
HIGHER RISK – Akita, Shiba Inu, Chow Chow, Dalmatian, Boxer, Collie, German Shepherd, West Highland White Terrier, Cocker Spaniel, French Bulldog
Are some dogs more sensitive than others?
Yes, different individuals of the same breed can be more or less sensitive to lactose due to factors such as age, diet or their specific microbiome (the community of microorganisms, including bacteria, fungi, and viruses, and their genetic material that exist in the gut).
Bottom line
Avoid feeding dogs over 3-6 months of age dairy products, especially milk and yoghurt. If you use cheese as a treat, go for Parmesan or aged/matured cheddar. But if your dog/s shows loose stools, foul-smelling stools or gas or passes more gas than normal within a few hours of feeding cheese, then it’s likely they are intolerant of lactose, especially if they are in the higher-risk breed group, but any dog can be lactose intolerant. If they regularly vomit within a few hours of being fed cheese (ir any other dairy product) then they are likely severely intolerant and at risk of serious illness if they continue to be fed cheese or or other dairy products.
