Most New Year's resolutions involve a certain amount of distasteful self-sacrifice. But I'd like to propose one for horseplayers that will be painless and potentially profitable. Moreover, it will serve the cause of justice and work against the rapacity of the Internal Revenue Service.

Every bettor should vow to keep a record of his wagers whenever he goes to the track in 1980. He doesn't need to hire an accountant to do any elaborate bookkeeping. All he needs to do is mark down his bets on his racing program, total his profit or loss for the day, and save the programs until the end of the year.

This procedure ought to be as fundamental a part of playing the horses as reading the Daily Racing Form. But betters generally don't keep records, and as a result, they cost themselves millions of dollars a year.

In the Tax Reform Act of 1976, Congfress decreed that a 20 percent withholding tax would be assessed on every race track payoff larger than $1,000, at odds of more than 300 to 1. Thus a better who got lucky and hit a $4,000 trifecta would actually collect only $3,200. The IRS would hold the other $800.

To the tax men who proposed it, and the politicians who voted for it, this procedure seemed sensible and fair. Why shouldn't gamblers pay taxes on their income like everybody else?

In practice, though, the withholding provision has amounted to confiscation rather than taxation. Citizens owe taxes only on net gambling winnings for a year, and few of them show a profit. A bettor who cashed a $4,000 ticket may not owe the IRS a penny at the end of the year. But in order for him to establish his offsetting losses, he will need a record of his wages.

If he is a typical bettor, he won't have those records. Knowing that he couldn't win a battle with the IRS anyway, he will probably surrender his withheld $800 without a fight.

The IRS withholds about $65 million a year from race track winnings, and while that may be a puny sum by government standards, it has had a significant impact on the racing industry. The tax has severely hurt some tracks, like Charles Town, which depend heavily on gimmick bets with big (and now taxable) payoffs.

And since 1976, the total income of the states from racing has been declining. "Most experts agree that the withholding tax has been a major reason for that," said Rich Rolapp, president of the American Horse Council.

Yet the IRS is stepping up its efforts to get every possible dollar from the withholding tax. When it went into effect, one question was never clearly answered: What happens if a horseplayer buys two $2 tickets on an exacta, and the exacta pays $700?

Most tracks viewed the two tickets as two separate $700 payoffs, requiring no withholding. But the IRS last month proposed a rule that would require tracks to "aggregate payoffs for the purpose of calculating withholding."

Agents recently discovered that The Meadows, a harness track in Pennsylvania, was still treating two $700 ticketrs in the old way, instead of taking 20 per cent from $1,400. So now the IRS is suing the track for the amount that should have been withheld, plus penalties. The practical effect of the new IRS policy, of course, will be to force horseplayers holding more than one ticket in the $600-to-$1,000 range to cash them at different windows.

Because of the harmful effects of the withholding tax, racing industry officials have been arguing for its repeal since the day it was instituted.

Last month, Sen. Harrison A. Willians (D-N.J.) introduced a bill to that effect. But nothing is likely to happen until Congress is considering a large tax package, and the withholding repeal can be inconspicuously inserted in it.

Not many politicians want to be identified as champions of tax breaks for gamblers.

Until they get some relief from Congress, horseplayers will have to fight their own battles with the IRS. It is ridiculous for bettors, who are already bucking enormous odds in a difficult game, to surrender 20 per cent of a big payoff without putting up a struggle. It is even more ridiculous for them to pay somebody else an additional 5 or 10 per cent to cash the ticket. But people do that frequently because they dread any dealings with the IRS.

A horseplayer who keeps a decent set of records during 1980 will at least have a shot at recovering money withheld from him in the coming year. Agents still may demand to see losing tickets or other proof of the losses, or they may choose to disbelieve a gambler on general principles. But horseplayers at least ought to make the IRS work to grab their money instead of submitting meekly to their confiscation.