Each dog has its own ideal weight. Generally they will weigh between 24-34kg tho smaller or bigger dogs may weigh more than this.
In the U.K. 35% of pet dogs are overweight, in the US as many as 59% are overweight (Association for Pet Obesity Prevention 2017).
Obesity is a massive health problem that will shorten your greyhound's lifespan. If your greyhound is over weight reducing this will give many heath benefits such as removing pressure on the joints red and reducing the risk of arthritis & cancer in later life.
You don't need a set of scales to check if your dog is over weight.
Ideally you should be able to see the faint outlines of the first three ribs. For a dog with a pronounced rib-cage this may not be the case. Some may show ribs even when obese.
The tips of the hipbones should be just visible and no more. A smooth back with no bones visible may indicate your hound is over weight.
There should be a pronounced "tuck" and tidy waist. Your dog should have good muscle tone and good hydration. Hydration can be checked using the skin pinch test. Ensuing regular nail care will help keep your dogs tendons healthy wich will aid with your dog's over all health.
When your dog retires from racing it is likely to be doing a lot less exercise than it was. Muscle can quickly turn to fat. It is important to adjust your dogs diet to his needs to ensure the proper weight. Your adoption group should be able to help you with your dogs race weight.
Remember your greyhound is not a lab!