Wind?

try a spoonful of natural yogurt in his food, keeps smells down.
My greyhound is one of the oldest dog breeds around, used by the ancient Egyptians, you can seen them in hieroglyphics in the same form as they are now. They were brought to Europe by Crusaders returning from the Middle East, you can see them in contemporary paintings and illustrations. There's one in the Bayeux Tapestry. Originally only aristocrats could own them, but now they will deign to live with us lesser mortals.
Unlike most breeds their shape and features haven't been changed, the ancients would recognise them immediately. They are built differently from other dogs though, larger heart and lungs, thin skin and hair, their spine is articulated differently to enable them to use their unique running gait, only cheetahs run the same way. they literally fly. Greyhounds can reach 40-45mph in six strides, but only in short bursts the rest of the time they are asleep usually on a sofa, on their backs, head dangling down, legs at weird angles, cheeks puffing. They are unique, get one of you can you'll never have a normal dog again, they are amusing, loving, cool and very clean, no doggy smell wet or dry.