The Millbrae men will be the team everyone is out to beat this term after last season's league and cup double but they kicked off with a bonus-point victory despite a tough examination by Graeme Young's side.
Ayr's other two tries were scored by winger Cammy Taylor and second-row Scott Sutherland. Scrum-half Peter Jericevich had a good day with the boot, converting all four tries.
County's points came from a try by Ruairidh Leishman plus three penalties and a conversion from experienced centre Brian Archibald.
A late try by centre Ruairidh Bonner gave Edinburgh Accies a win over Glasgow Hawks at Raeburn Place.
The visitors, who won the RBS National League last year, led 20-16 going into the last three minutes before Bonner scrambled over. His subsequent conversion miss could have proved costly but replacement Jack Steele, making his debut for Hawks, was short with a long-range penalty attempt that proved to be the last kick of the ball.
Winger Jamie Farndale also scored a try for Accies and their other 11 points came from the boot of Bonner. Hawks' points came from tries by winger Tom Steven and captain Ross Miller, with Mike Adamson kicking 10 points.
Last year's runners-up Gala started with a 31-14 home win over Currie.
They also grabbed a bonus point, thanks to tries from second-row pairing Craig Borthwick and Opeta Palepoi plus centre Alan Emond and winger Grant Somerville. Debutante stand-off Dave O'Hagen kicked the rest of the points.
New stand-off Joe Reynolds touched down for Currie while scrum-half Richard Snedden kicked three penalties.
Melrose saw off Heriot's 30-13. Scotland under-20 winger Damien Hoyland led the way with two tries on his debut for the Greenyards club. Centre Andrew Skeen and scrum-half Bruce Colvine also scored and Joe Helps kicked 10 points.
The Heriot's tries came from winger Colin Goudie and the side's new hooker, George Turner, with stand-off Graham Wilson kicking a penalty.
Aberdeen Grammar made the long trip to Hawick and headed back north with a 23-16 victory.
Hooker Sam Bingham was the unlikely hero for Grammar with two tries while scrum-half Morgan Ward also went over and stand-off Rob Aloe kicked eight points.
Centre Gary Johnstone got the home side's only try on their return to the top flight, with Gregor Hunter kicking the rest of the points from stand-off.
o See Page 15 for results