Normally, the sounds of thunder cascading down the stretch of the two New England major thoroughbred tracks -- Suffolk Downs and Rockingham Park emanate from horses. Now, the thunderclaps are coming from New England horsemen, who say they need a bigger share of the simulcasting pie to survive.The board of directors of the New England Horsemen's Benevolent and Protective Association sent the management team of Rockingham Park in New Hampshire notice that anything less than a 7.5% percent share of simulcasting revenue, beginning with opening day, June 10, would be unacceptable.Negotiations are ongoing in New Hampshire as well as in Massachusetts, where an extension of the racing law is due to expire June 30. If a new law isn't in place, racing would be governed under statutes enacted in the late 1970s.Many New England horsemen are faced with the prospect of moving to more lucrative circuits, working for someone else, or finding a different line of employment because New England purses haven't kept pace with other jurisdictions.Manfred Roos, the newly-elected president of the New England HBPA, has said it's now-or-never time. At the currrent Suffolk Downs meet, purses have averaged $72,000, one of the lowest averages in the Northeast and Mid-Atlantic region.The statute in place when simulcasting began awards horsemen 3.5% of revenue. The law was enacted before the true impact of simulcasting could be determined, and horsemen want a higher percentage. The 3.5% is one of the lowest percentages in the country, yet Massachusetts has some of the highest pari-mutuel takeout rates: 19% on win, place, and show wagers, and 26% on exotic wagers.Suffolk Downs has bucked the statute and paid horsemen 5.3% of simulcasting revenue. The HBPA would like 7.5% of the pie, but Suffolk Downs officials said they can't afford to pay more than they are now.Should an agreement not be reached between racetracks and the Massachusetts legislature, some horsemen with the top-end stock may ship to tracks at which purses are competitive in relation to the product.Others may race at the Brockton Fair, which will return this summer after many years, and the Three County Fair in Northampton. The residents of Great Barrington in western Massachusetts voted a third time against simulcasting at the fairgrounds, but it is unclear what power a new state racing law would have over local government. The fairgrounds owner wants to offer live racing, but only if he can simulcast year-round.