6 month yellow lab

Question
hi i have a great 6 month old yellow lab puppy. she has been great since we have had her. she had vaginitis earlier on in her life. she plays, exercise, and eats perfectly fine but the last few days she hasn't been eating very well 1 cup full of food in 2 days. our vet told us to use adult food because she was choking on puppy food cause she just gobbles it up straight away. she is fine eating it but she isnt bothered about eating much now. could this be because its an adult food or coming into heat? we noticed a few spots of blood but not sure where its came from and when i took her out the other day the male lab that walks past us regularly went for her trying to mount her so is that a sign that she has came into heat this is my first dog so not too sure. be grateful for any advice you could give me thanks

Answer
There are several things going on here.  Start out evaluating her using http://www.longliveyourdog.com/twoplus/RateYourDog.aspx  If she is overweight, cut back a little and she should regain her appetite once she loses a little.  

6 months is on the early side for her to come into heat, but it is possible.  None of my Labs ever let it interfere with eating, but it does happen.  I would see how things go the next few days.  If she doesn't start eating a little more, it could be something else.  You may want to check with the vet.

The second and third weeks are when the most risk of accidental breeding is. Don't take this lightly. She will do anything to get loose and get to a male. Once loose, an accidental breeding and an unwanted litter is far from the worst that can happen. Such breedings can also result in fatal infections. She can get killed when she dashes heedlessly across the road in front of a car. Avoid that male.  

The adult food should be OK as long as the calcium is less than 1.5%, actual, not the minimum on the bag.  Check their website or call customer service.  

If she ever does return to gobbling her food, it can be controlled.  There are not one, but 2 easy, tested, effective ways to control rapid eating. You can spread the food out on a cookie sheet or something. Some of my friends just throw it on the floor of the crate. You can put large rocks in the food dish, much to big to swallow. Either way, the dog can't gulp down one big mouthful after another.