In an effort to attract more and better race horses to Maryland's tracks, a State Senate committee yesterday unanimously approved legislation giving owners a larger share of the purse on exactatrizacta betting.

The legislation, sponsored by Sen. C. A. Porter Hopkins (R-Baltimore Co.), is expected to come for a preliminary vote on the floor of the Senate early next week. At least one senator, Julian Lapides (D-Baltimore Citv), has indicated strong opposition to the measure.

The measure approved by the Finance Committee yeaterday, would raise the owner's share of earnings on exacta betting from 16 percent to 19 percent as of July 1. The owners' share of the trizacta betting would be increased from 16 percent to 23 percent under the legislation, which parallels a measure introduced in the House of Delegates.

The measure had been pushed hard by Maryland's two main breeder associations, which argued that the quality of racing in Maryland was declining because there was not enough money available for breeders.

The result of the legislation, if it is approved, would be to reduce the amount of money that bettors can win.

In other racing-related action, Clark's committee has taken steps to calm fears that the schedule at Pimlico would be disrupted this summer by legislation rearranging the allocation of summer dates.

The committee approved the reallocation of 45 summer racing dates, but added an amendment to the bill that would postpone the effective date of the legislation until July 1979. If that bill wins passage in the Senate, the House will have to agree to the delaying amendment before the bill can become law.