What is the effect of beer on dogs? More specifically, a large black lab.

Years ago at a keg party the keg developed a slight drip. To keep from
making a mess we put a bowl under the tap to catch the beer. We did
notice the host's dog hanging around the keg, but didn't notice how
much he might have had to drink. Later on we observed that the dog was
acting funny and the next day he spent laying under a shade tree
burping every once in awhile. He suffered no long term problems from
his binge and never drank again as far as I know.

Light beer or dark beer?  This study said that dark beer makes a
difference to heart health:
http://www.checkout.ie/WorldReport.asp?ID=22

Best regards,

Omnivorous-GA

If ingested, alcohol can potentially result in vomiting, diarrhea,
lack of coordination, central nervous system depression, difficulty
breathing, tremors, acidosis, coma and even death. 
http://www.pet-dog-cat-supply-store.com/dog-hazards.php for more dog
safety information.