If Congress cannot do much for your dog Fido, it can at least lend a helping hand to one of Fido's best friend.

It's a complicated story, but the gist is that the House Agriculture Committee has approved a sweet break for the folks who make Fido's food.

The committee this week, tentatively passing a new sugar price stabilization bill, voted to free pet food makers from sugar import quotas.

The exemption was achieved by lumping pet foods in the same category with livestock feed, which also would be free to use non-quota sugar.

What this could mean eventually in the complex world of quotas and international trading is that pet food makers could buy their sugar for less than, say, Fido's owner could buy sugar for his breakfast coffee.

That is not to say the world is going to the dogs. It is to say that Reps. Edward R. Madigan and George M. O'Brien, Illinois Republicans, made a winning argument on behalf of a sugar-using dog-food maker at home.

Madigan, a member of the committee, presented the pet-food amendment for O'Brien, whose district includes a General Food Corp. dog food plant at Kankakee.

An aide to O'Brien explained that the congressman was concerned because the plant uses sugar, but was worried more that the blind whose seeing-eye dogs need food might be affected by the quota situation.

Was General Foods as concerned? "They certainly didn't object to this amendment," said the O'Brien aide.

No one is certain how much sugar is used in pet foods, but it is estimated that American dog food producers may use as much as 80,000 tons a year.

About a fourth of that is used by General Foods in the production of its GainesBurger patties, the market sales leader in soft-moist dog foods.

William Taylor, a General Foods spokesman at White Plains, N.Y., said the sugar is used as "a flavor enhancer, to retain moisture and to help as a preservative.

Taylor said that exempting pet food from import quotas might, in the future, help "forestall or minimize" increases in the price of Fido's fare.

According to Wayne Fletcher, a Madigan assistant, the committee this time around was merely reasserting what is had done in a 1974 sugar bill that was vetoed.

When a question arose about whether pets could be classified as livestock; he said it was resolved by checking a Webster's dictionary.

While the House may have no problem with the pet-food language, the bill may find a critic when it reaches the Senate - John Melcher (D-Mont.), a veterinarian.

Speaking as Dr. Melcher, the senator said that while some dogs are crazy about candy, they don't need sugar.

"Ordinary sucrose - table sugar - is tough on them and we don't recommend it. Dogs sometimes have intestinal inflammation and diarrhea from sugar. Cats are the same way. Cats and dogs need more protein than sugar."

Sugar, Melcher continued, "tends to make Old Shep fat. Obesity leads to the same problems that we humans have. There's no need to have obesity dogs, even if they are house dogs."

Melcher said that he will look closely at the bill when and if it is taken up by the Senate.

He couldn't resist a pun. "I'll be suspicious of the bill when it comes along. Sounds like some kind of gravy train coming," he said.