Since dogs are a different species from human beings, we can’t assume that food that suits our bodies equally suits their needs. Sometimes giving our pets human-type food is okay and sometimes it is merely unwise, but there are instances when it can be disastrous or even occasionally fatal. Human beings (and guinea pigs) cannot, for example, manufacture their own Vitamin C. Dogs and cats can. Dogs need a good amount of thiamine, but they (and human beings) don’t need taurine, which cats do.

Dogs can be very sensitive to some common foodstuffs (like onions and certain nuts), and chocolate, especially black chocolate, in substantial quantities can actually make them seriously ill or – in the case of smaller dogs – even kill them.
Here is some useful information:

Should pets drink milk?
Most people would consider milk an excellent foodstuff for dogs and cats, but pets older than three months do not require milk in their diet, and (like people) many pets are lactose-intolerant. Lactose intolerance is more common in pets, especially cats, than in human beings.
A pet that is lactose-intolerant will probably have diarrhoea, sometimes accompanied by vomiting.
Although pets don’t need milk, they do enjoy it, so if you want to feed your adult pet milk you can purchase a lactose-free pet milk from your vet or some supermarkets.

How about fat in the diet?
   Too much fat is just as dangerous for your pets as it is for you and will contribute towards obesity, diabetes and arthritis. Even a single over-fatty meal can cause pancreatitis in dogs. It is less common in cats. Pancreatitis in humans is usually caused by imbibing alcohol. In pets, it’s caused by eating fatty foods, like braaivleis leftovers, fat stripped from steak and chops, and marrow bones (though dogs love these).
A dog with pancreatitis is a very sick dog indeed and will vomit and reject food. It will be lethargic and often dehydrated and will often evince pain when touched in the front of the abdomen near the end of the rib cage.

What about raw fish?
Raw fish (especially tuna and salmon) contains a substantial amount of an enzyme called thiaminase that breaks down thiamine in the food. When fed fish regularly for an extended period, cats and dogs can become quite ill and suffer seizures, stupor and coma and might even die.
   Thiamine is familiarly known as Vitamin B1 and is essential for dogs and cats as they cannot synthesise their own.
   One can avoid this kind of illness quite easily by giving pets a balanced healthy diet. Do not give fish as a primary foodstuff. Also note that some of the cheaper meat-based pet foods sometimes contain sulphur preservatives that will remove any thiamine present in the diet.

Is liver recommended?
In moderation, yes, cooked liver is fine and will not cause any problems. But bear in mind that liver is high in Vitamin A. If pets (especially cats) are fed a high liver diet for more than two years, there is a risk of a condition called Hypervitaminosis A.
This ailment causes a condition where bones fuse together. It is common in the spinal column and will cause a cat to walk very stiffly and awkwardly.
Cats are particular at risk as they love liver, and owners are likely therefore to feed faddy animals too much of this otherwise excellent food.

Can dogs and cats be healthy vegetarians?
Do not feed your cat a vegetarian diet. Cats cannot manufacture taurine, and taurine is found only in meat. Vegetarian cats can go blind, contract heart disease, and have immune system deficiencies.
Dogs can be fed a vegetarian diet, but one has to be very careful, and it is essential to include soy and other protein sources. A diet with some meat is preferable unless you are really careful to include adequate daily protein.

What about an all-meat diet?
This is dangerous because meat is very low in calcium and very high in phosphorus. One needs a proper calcium/phosphorus balance for healthy bone formation and growth. An all-meat diet will result in poorly ossified bones, rickets and other health conditions.

(Adapted from an article by Dr Cam Day in the Robina Veterinary Surgery Newsletter)