I agree with LindaH--gas in dogs is not really related to air ingestion when gulping food but to what they are eating and sometimes the quantity they are eating.
The treats you were using to train with that made his stool runny are also probably culprits--they will cause gas too. I use a lot of the dogs own kibble for training and if I'm using a really high value treat for something particular in training I reward with VERY small quantities. I've noticed that there is a tendency for many people to give a lot more food as a reward than a very small amount of high value food when rewarding.
By the way--I would be very reluctant to hand feed a puppy to slow down eating--gulping food and eating rapidly in wild canids is a positive when it comes to survival--dogs are pretty much designed to eat that way. I've raised enough male puppies to tell you that if you intend to show him (as you've indicated) you'll come to rue the day that you screwed around with his eating (speed and gulping) when he hits puberty and as many young males do, stops eating well since his mind is now on girls rather than food.
If you are determined to slow his eating down do it with a large pan and spread the kibble out so he has a harder time grabbing mouthfuls.
But I for one would recommend leaving his eating habits pretty much alone.
The treats you were using to train with that made his stool runny are also probably culprits--they will cause gas too. I use a lot of the dogs own kibble for training and if I'm using a really high value treat for something particular in training I reward with VERY small quantities. I've noticed that there is a tendency for many people to give a lot more food as a reward than a very small amount of high value food when rewarding.
By the way--I would be very reluctant to hand feed a puppy to slow down eating--gulping food and eating rapidly in wild canids is a positive when it comes to survival--dogs are pretty much designed to eat that way. I've raised enough male puppies to tell you that if you intend to show him (as you've indicated) you'll come to rue the day that you screwed around with his eating (speed and gulping) when he hits puberty and as many young males do, stops eating well since his mind is now on girls rather than food.
If you are determined to slow his eating down do it with a large pan and spread the kibble out so he has a harder time grabbing mouthfuls.
But I for one would recommend leaving his eating habits pretty much alone.
