I'm assuming she means for racing since she asked if they are good racing bloodlines.
The real factor is usually not just who the sire and dam ar, but what they have done recently. I did not look up the info, but your best bet is to go to BRISNET or Equibase online and pull a calaog page for her - this will show what recent winners are in the family and what black type there is in the current and last generations. I do not go back much further than that, as most horses have black type 3rd generation out.
If you are not familiar with black type or looking at a catalog page, you should probably contact someone who is - it is quite an education to get into breeding. It may seem counter-intuitive, but you may be looking at 2 different schools of thought depending upon whether you plan to breed to race or breed to sell. If you plan to breed to race, performance up close (current to 2nd generation) is still important, but you may be choosing an older established sire, or a sire with consistant winners but who may not have had a "big" horse like a Breeders Cup or Derby winner. If you are possibly planning to sell (racing your own can be VERY expensive), you need to look at up and coming sires and commercial sires and that can be more tricky. If the young sire is already "hot" they may be too expensive or may cool off. If they will be a freshman sire in 2013 or their first crop is set to race in 2013 it can be a real crap shoot and your foal could be pretty worthless if the sire is a dud when your foal comes to sale.
Not an easy thing, and without running a produce report on the dam of your mare I cannot tell if this mare is worth breeding. That said, I like Posse, but would like to see a stronger dam line on your mare and a better race record. Now if she has a full sister or brother who has won a Graded Stakes, that could help. Also, how is her conformation?
Good luck and have fun getting educated about breeding in general - it is way to expensive and important to not learn all you can before making the leap.
I didnt assume for racing, since a lot of people post here asking about bloodlines of their horses without wanting to race. I would hope she wouldnt want to breed this mare for racing, the mare herself eeked out a single win in 21 starts, and the dam line certainly isnt strong enough, but for a show broodmare she might be just fine.
I have a nice Posse mare that is in foal to Munnings. Posse is a nice stallion but like others said this mare is very week on performance. For comparison mine is a 2 yr old MSW winner and made over $30k in 6 starts before getting hurt while on R&R... she is out of a stakes winner that is also a stakes producer.
owner and friend of members of the Limping And Majestic Equine Society.
Dam was third in a stake once, and dam is a half sis to a horse that was 2nd in a stake once. Other than that its back to the 3rd dam to find anything worth noting, which would be the 4th dam of the resultant foal.
OTOH, I did find the following info about Posse as a broodmare sire on his page at the stallionregister.com:
"Posse is the sire of 12 dams of 9 foals, 3 rnrs (33%), 2 wnrs (22%), 0 2yo wnrs (0%), 2.32 AEI, 1.32 CI; 1 sw, Leading Earner: All Squared Away ($168,638)."
Not a big sample at all, but the numbers are nice to look at.
Jessi Pizzurro ~~ Pennyroyal Stables
Racehorses, OTTBs ~~ 330 383 1281
Courage is being scared to death and saddling up anyway. -- John Wayne
If she is a good mover and sound, enjoy her as a sport horse.
I like Posse a lot and my mare is in foal to him. He gets a lot of good runners and some really fast horses like Kodiack Kowboy and Caleb's Posse. But your mare's female side is not quite strong enough to be worth breeding since she herself did nothing on the track.