I've been told recently by a friend who is very into home cooking for dogs that it is better not to add fresh or that chopped and from a jar, into the food while cooking but to wait and add it to the food later. She said that cooking destroys some of the nutritional value of the garlic.
When I have the time I plan on looking this up to see if it is enough of a difference for me to worry about.
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I just found this
From Garlic Central websiteQuote:
Preparing Garlic
Remember that a single bulb of garlic usually contains between ten and twenty individual cloves of garlic. Individual cloves are covered with a fine pinkish/purple skin. The head of cloves is then covered with white papery outer skin. Don't confuse cloves and bulbs! Neither the inner nor outer skins should be eaten.
To prepare garlic, first strip off some of the papery covering from the bulb. Now ease out as many cloves as required. Garlic cloves come in a wide variety of sizes, so the numbers given in a recipe should be treated as a rough guide only. Once you get used to cooking with garlic you will probably find yourself using more than the recipe states.
In general with garlic, the finer the chop the stronger the taste. Crushed garlic has the strongest taste of all and if used raw is only for the real aficionado. When cooked whole garlic has a much milder, rather sweet taste. There is a famous recipe "chicken with forty cloves of garlic". It should go without saying that these are whole garlic cloves not crushed!
Garlic also mellows the longer it is cooked. Garlic added at the end of cooking will give a stronger taste than garlic prepared the same way but added earlier.
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So besides nutritional reasons, it sounds like cooking the garlic may take away some of the reason why some give it -- to help repel bugs.
**** I would also like to add that for those that give garlic to your dogs, it would be a good idea to make sure that your vet is aware of this. Garlic is a herb and as such can interfere with different types of medicines. If your vet has this in your dog's folder he will then be able to advise you if you need to stop using garlic while your dog is on certain medications. Also, it would be good for the vet to have this knowledge in case your dog is one of those dogs that do have a reaction to garlic.