There are several pituitary hormone deficiencies that can occur in dogs, but the most visibly noticeable example is pituitary dwarfism. This condition causes a dog to be significantly smaller than any littermates or other puppies of normal size.
The dog will be proportionate, but will usually retain puppy fur and may develop at a slow rate mentally as well. There are a number of things that cause pituitary dwarfism in dogs, including intentional breeding over generations in order to develop a smaller breed of dog.
Symptoms of Pituitary Dwarfism
When a dog's pituitary gland fails to produce the proper amount of growth hormone (GH), pituitary dwarfism may result. Puppies will appear normal at birth, but will fail to grow at the same proportion of other dogs born at the same time. This will usually begins to be the most noticeable at around 3 months of age when the puppy looks like its littermates, but is substantially smaller in size. A puppy's fur will remain soft and teeth may not grow at the normal rate. The bark will continue to sound like a puppy's bark when siblings are starting to sound like older dogs.
This condition may also cause symmetrical hair loss to occur along the sides of the body, and may lead to deformities in the legs or other areas of the body. Physical and mental growth may be noticeably affected when a dog with pituitary dwarfism fails to progress normally in those areas. This disease is most notable in German Shepherds, but has been discovered in other breeds as well. The affected gene is recessive, thereby leading to the assumption that an affected puppy has adopted the gene from both parents.
Causes of Pituitary Dwarfism in Dogs
The cause of pituitary dwarfism can be due to one or more conditions that affect the rate of production of GH. The pituitary gland itself may simply fail to develop properly or could be hindered by any number of infections or viruses. Cysts or tumors within the gland can interrupt production of the hormone as well. It is not common for this disease to be naturally occurring in dogs, but it can affect breeds like the:
- Collie
- Labrador Retriever
- Giant Schnauzer
- Shih Tzu
Over the years many breeds have been intentionally bred to retain one or more miniaturized traits caused by lack of growth hormone. Bulldogs have a shortened torso and a shortened muzzle, and dogs like the Dachshund and Lhasa Apso have shortened legs. Many breeds which have been affected by pituitary dwarfism or have been genetically bred for smaller features are more susceptible to additional health conditions. Dogs with a shortened torso or shortened legs may be more apt to have problems with disks in the back or hip dysplasia.
The reproductive system may also be affected. Having a shortened muzzle may lead to breathing problems, as well as an increased number of infections in the eyes, nose, teeth and gums.