Eggs are highly nutritious food, providing a vast range of highly digestible protein, fatty acids, vitamins, and minerals. An egg can be a healthy treat, each one providing 60 calories, with 6g or protein and 4 mg of fat. We have to be aware of canine calorie intake as dogs need fewer calories than we do; so adding treats to a balanced, complete diet can lead to obesity. But what about raw eggs?

The controversy over the feeding of raw eggs centres in the danger of bacterial contamination as opposed to any potential nutritional benefit lost by cooking. There is no evidence of nutritional benefit from feeding raw eggs, but there may be some degradation in vitamins and mineral content. It is possible that the egg protein is more digestible when cooked, this was found in one small human study that measured digestibility (1). The danger of bacterial contamination is also sparsely corroborated. Although individual dogs have suffered disease from contaminated eggs, there have been no major outbreaks in dogs. Dogs have eaten raw eggs for centuries and the majority have not succumbed to severe disease. We will look further at the risk of bacterial contamination.

Major bacteria

Salmonella is the foremost culprit in bacterial contamination of raw eggs (2,3). Another bacteria, E. coli, may also be involved. Both bacteria can cause gastrointestinal disease ranging from mild nausea and abdominal discomfort to profuse vomiting and bloody diarrhoea. Initially, dogs may appear lethargic, lose their appetite and appear depressed. They may then develop a high temperature, vomiting and diarrhoea. Dogs with underlying conditions that suppress their immune systems, puppies and old dogs are more likely to contract severe disease if they eat a contaminated egg. Both diseases are zoonotic, so can be spread to humans through an infected dog’s faeces, vomit or saliva. Immunosuppressed people will also suffer severe disease. 

If you suspect your dog has contracted salmonella or E. coli infection… 

First, contact your vet and pay special attention to hygiene. Wash your hands after handling your dog or their excreta. Wear gloves when cleaning up after them. Handle food, water bowls and toys carefully to avoid becoming infected. Disinfect any areas which have been contaminated with vomit or diarrhoea. Severely affected dogs will need hospitalisation, intravenous fluid therapy and may need antibiotic therapy to prevent sepsis. 

So what should I do?

As bacterial infection is possible, it may be safer to feed cooked egg. Perhaps chop up a recently boiled hard boiled egg or scrambled egg with no fat or spices added. If you want to feed raw eggs, then feeding one or two carefully sourced and handled eggs a week is unlikely to harm a healthy dog. 

How should I store eggs?

Eggs should be stored below 200 C as this reduces the growth of the bacteria. This temperature also preserves the yolk membrane, so fewer bacteria transfer into the rich food source of the yolk. Temperature fluctuations encourage bacterial growth and penetration through the shell and egg membrane. Eggs should also be brought to room temperature before cooking. Cracked and dirty eggs should not be used as the bacterial load may be higher. Most large-scale commercial egg producers in the UK adhere to a strict code of practice which virtually eliminates salmonella. However, some eggs sold in the UK are imported and bought by wholesalers. These eggs may not be subject to the same controls. Sourcing your eggs from a free range, high welfare source protects the welfare of the hens and reduces the possibility of poor standards encouraging salmonella contamination. 

The nutritional bits…

Egg white contains avidin which inhibits the availability of a useful vitamin, biotin (B7). Egg yolks contain high levels of biotin so feeding a whole egg probably negates this effect. A single egg fed infrequently will not cause biotin deficiency (which results in poor skin and coat quality). However, you may need to monitor your dog if eggs make up a large part of their diet. 

Feeding a lot of eggs can result in a particularly unpleasant side effect, flatulence. Introduce eggs carefully and slowly into a dog’s diet to reduce this eye-watering effect. Egg allergy is possible in the dog but rare.   

What about the shells?

Some people advocate feeding eggshell as a source of calcium for your dog. It is important for your dog’s health that they receive a balanced complete food so they should not require extra calcium in their diet. Supplementing calcium during pregnancy can lead to eclampsia post-whelping which is a severe disease resulting from calcium deficiency. If a pregnant bitch is given supplementary calcium her body will not manage her own calcium levels and when the pups are born she will not be able to maintain her blood calcium levels and develop tremors, seizures and a slow heart rate, this is rapidly fatal if untreated. If you do want to feed eggshell to your dog it is best to grind it in a coffee grinder or blender so that he shards do not cause oral injury. 

In conclusion… 

Cooked eggs are safer for dogs as any contaminating bacteria are killed. However, the risk of feeding a raw egg to a healthy dog infrequently is very small. Careful food hygiene and storage reduces the chance of contamination. Consider this more carefully if your dog is unwell, very young or old. Also, consider your health status and that of other family members and pets. 

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References:

  1. Evenepoel P, Geypens B, Luypaerts A, Hiele M, Ghoos Y and Rutgeerts P. Digestibility of cooked and raw egg protein in humans as assessed by stable isotope techniques. (1998) The Journal of Nutrition 128 (10):1716-1722
  2. Martelli F and Davies RH. Salmonella serovars isolated from table eggs: An overview. (2012) Food research international 45 (2):745-754
  3. Harker KS, Lane C, Gormley FJ and Adak GK. National outbreaks of Salmonella infection in the UK, 2000-2011. (2013) Cambridge University Press 2013