Question: What is the average weight for a male and a female mastiff at 1 year of age? What is the average height for the same dogs?
Answer: I am guessing you are asking about the English Mastiff, so I will take my answer from there. At a year of age giant breeds have most of the height they are going to obtain. However this is only a broad average as the genetics of the line play a huge role in how tall and large the dog is! Males at minimum usually 30 inches and females 27 inches. At a year, giant breeds are still putting on muscle mass and have not reached their full weight. They may even appear to be a bit thin as they have yet to fill out. The average full grown weight for a female would be around 150 lbs and a male is about 180 lbs. Your dog should weigh a bit less than that as he or she has yet to reach his adult weight. Like I said, the genetic variation of the line will have a lot more to say about these numbers than I do. You can also get a good idea of your dogs final size by looking at his parents and his pedigree.