A common breeding practice for pet dogs is mating between close relatives (e.g. between half- and full siblings). Inbreeding depression is considered to be due largely to the expression of homozygous deleterious recessive mutations. Outcrossing between unrelated individuals, including dogs of different breeds, results in the beneficial masking of deleterious recessive mutations in progeny.
Clip the dog's nails. If left untrimmed, a dog's nails can curl under into the paw pads or twist toes in a way that causes joint damage. To keep your dog's nails short, clip them regularly, depending on how fast his nails grow. If you can hear his nails on the ground when he walks, that means his nails are touching the ground, and are too long. 
The scientific evidence is mixed as to whether companionship of a dog can enhance human physical health and psychological wellbeing. Studies suggesting that there are benefits to physical health and psychological wellbeing have been criticised for being poorly controlled, and finding that "the health of elderly people is related to their health habits and social supports but not to their ownership of, or attachment to, a companion animal." Earlier studies have shown that people who keep pet dogs or cats exhibit better mental and physical health than those who do not, making fewer visits to the doctor and being less likely to be on medication than non-guardians.
Rinse your dog thoroughly. As long as you see dirt or soap bubbles in the water coming off of an area, keep rinsing. You can use the same method you used to soak the dog's coat before shampooing. If your dog is too afraid of running water or the bath in general and can't be done on your own, there are veterinarians who can give proper sedation, not too much, to allow you to groom in a couple of hours or can groom the dog themselves. Touch the dog all over to feel for any shampoo especially the chest area and in between the legs they are hard to get. To test it, rub the fur in between you fingers and pull softly, if it feels squeaky then it's clean.
^ Wood, Lisa; Martin, Karen; Christian, Hayley; Nathan, Andrea; Lauritsen, Claire; Houghton, Steve; Kawachi, Ichiro; McCune, Sandra (2015). "The Pet Factor – Companion Animals as a Conduit for Getting to Know People, Friendship Formation and Social Support". PLoS ONE. 10 (4): e0122085. Bibcode:2015PLoSO..1022085W. doi:10.1371/journal.pone.0122085. PMC 4414420. PMID 25924013.