Dog — spay/neuter (recommended unless bred; timing & cancer/marking prevention)
Source: first-hand Merck Veterinary Manual pet-owner text, saved to source_file; every claim below is a C1 byte-substring of it.
Claims
All dogs should be spayed or neutered unless they are being bred.Female dogs should be spayed at around 6 months old, before their first heat (breeding) cycle.Doing so helps prevent mammary (breast) cancer and uterine cancer.Male dogs should be neutered when they are 5–10 months old.This can help prevent urine marking and other behavior problems.Large-breed dogs should be fed smaller meals at least twice a day to prevent their stomachs from bloating.For most dog breeds, you should always be able to feel the animal's spine and ribs, but not see them.Some breeds with breathing issues, like French Bulldogs or Pugs, may not handle long exercise sessions well but can still benefit from shorter walks.Some breeds, like Irish Setters and Dalmatians, are more energetic than calmer breeds, like Newfoundlands or Basset Hounds, and might need more attention.Most dogs reach adulthood at 9–12 months, but large and giant breed dogs can take almost 2 years to become adults.Depending on their breed, once puppies become adults, they should be switched from puppy food to adult dog food.Does My Dog Need to Be Spayed or Neutered? The surgery to prevent a dog from breeding is called spaying in females and neutering in males.
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Source: pdf-raw/companion-care/companion_dog_husbandry_src.txt · https://www.merckvetmanual.com/dog-owners/routine-health-care-of-dogs