Potential Health Problems
There are many health issues that Labradors can suffer from.
Responsible breeders try to eliminate as many of these as
possible. We make every attempt here at Hill Country Labradors
to breed healthy, sound dogs. However, we understand that
many diseases, defects and disorders are polygenic (multiple
gene involvement) and it is impossible to breed perfect dogs.
We are grateful to have the testing available to help us identify
many congenital defects and diseases and have spent countless
hours and resources attempting to eliminate these problems
from our breeding program. Generally speaking the two most
common problems seen in Labradors are in their eyes and joints.
We are going to cover these but in no way are we trying to
say that these are the only potential problems a Lab can have.
Like most breeds, Labs can have epilepsy, allergies, heart
murmurs, OCD, and the list goes on. The good news is that
these other potential problems are rare and breeders have
done such a great job over the past few decades that we have
almost eliminated these problems. Of course, we are referring
to the Labs that are bred by reputable breeders and not the
ones being bred by backyard breeders or puppy mills, without
clearances or concern for health or genetics.
Eyes
CERF Exam All breeding dogs at Hill Country Labradors are
examined by a veterinary ophthalmogist board certified by
the American College of Veterinary Ophthalmologists (ACVO).
The findings are forwarded to the Canine Eye Registry Foundation
(CERF) for their research.
An eye certification exam consists of a thorough examination
of the eye from all directions. First the pupil and iris are
examined for any abnormalities, such as small holes called
iris colobomas. Then the pupils are dilated with eye drops
called tropicamide. Once the pupil is well dilated the examiner
will usually illuminate the eye with a penlight or transilluminator
as he looks for large, obvious abnormalities. The eye is then
examined in detail with a slit-lamp biomicroscope that will
reveal any smaller abnormalities located in the cornea, lens,
anterior chamber and front region of the vitreous.
The types of defects that may be noticed during this part
of the exam include cataracts (opacity of the lens) , imperforate
puncta (unopened tear ducts), distichia (extra eyelashes)
corneal dystrophy (cholesterol development in the cornea),
persistent pupillary membranes, persistent hyaloid remnants,
and vitreal degeneration.
The last step uses an ophthalmoscope and a focusing lens to
examine the retina or fundus. This part of the examination
may reveal such problems as Progressive Retinal Atrophy (PRA),
Retinal Dysplasia, colobomas, choroidal hypoplasia and optic
nerve hypoplasia (Collie Eye Anomaly), and retinal detachment.
All dogs used for breeding should have annual CERF exams,
especially if any recognized heritable eye disorder is known
to be present in the breed. Reputable breeders will have puppies
examined before being sold if the breed is known to have any
early onset, heritable eye disorders.
Progressive retinal atrophy or degeneration (PRA or PRD) is
the name for several diseases that are progressive and lead
to blindness. First recognized at the beginning of the 20th
century in Gordon Setters, this inherited condition has been
documented in over 100 breeds, and mixed breed animals as
well.
Normally, the photoreceptors in the retinas develop after
birth to about 8 weeks of age. The retinas of dogs with PRA
either have arrested development (retinal dysplasia) or early
degeneration of the photoreceptors. Retinal dysplastic dogs
are usually affected within two months of birth and may be
completely blind by one year. Dogs with retinal degeneration
are affected from one year to eight years of age and the symptoms
progress slowly.
PRA worsens over time. The affected animal experiences night
blindness initially because the rods are affected first. The
condition progresses to failed daytime vision. There is no
cure for PRA. Fortunately, testing is available. In the last
several years, DNA is being used to identify which genes are
responsible for PRA. In one form of PRA called ‘rod
cone dysplasia 1' (rcd1), which affects Irish Setters, the
gene mutation has been identified.
Hip Dysplasia
Like most large, heavy breeds, the Labrador is prone to have
a genetic predisposition to Canine Hip Dysplasia (CHD). Canine
hip dysplasia has puzzled researchers for the past 50 years.
Although certain aspects of this degenerative, sometimes painful
condition are now understood, much must still be learned about
helping afflicted dogs and preventing the increasing incidence
of the disease. Originally, the only means at the breeder’s
disposal was to look at the dog’s movement in order
to judge whether the hips seemed sound. But many dogs with
wretched movement never develop hip problems, and dogs with
excellent movement can develop degenerative joint disease
(DJD) of the hip joint.
Hip dysplasia literally means an abnormality in the development
of the hip joint. It is characterized by a shallow acetabulum
(the “cup” of the hip joint) and changes in the
shape of the femoral head (the “ball” of the hip
joint). These changes may occur due to excessive laxity in
the hip joint. Hip dysplasia can exist with or without clinical
signs. It may or may not be bilateral (affecting both the
right and left hip joints) .When dogs exhibit clinical signs
of this problem they usually are lame on one or both rear
limbs. Severe arthritis can develop as a result of the malformation
of the hip joint and this results in pain as the disease progresses.
Many young dogs exhibit pain during or shortly after the growth
period, often before arthritic changes appear to be present.
It is not unusual for this pain to appear to disappear for
several years and then to return when arthritic changes become
obvious.
Hip dysplasia is a developmental condition and is not considered
a congenital anomaly.
Dogs with hip dysplasia appear to be born with normal hips
and then to develop the disease later. This has led to a lot
of speculation as to the contributing factors which may be
involved with this disease. This is an inherited condition,
but not all dogs with the genetic tendency will develop clinical
signs and the degree of hip dysplasia which develops does
not alway seem to correlate well with expectations based on
the parent’s condition. Unlike many other genetic disorders,
however, the occurrence of hip dysplasia cannot be traced
to a single gene; it is polygenic (caused by many genes).
As with other polygenic disorders, environmental factors play
a 50% role in the expression and degree of hip dysplasia.
Dogs with no genetic predisposition do not develop hip dysplasia.
In recent studies it has been observed that 2 out of 10 puppies
born of so called HD-free parents will develop hip dysplasia.
The risk increases to 5 out of 10 if one of the parents does
in fact have hip dysplasia; 8 out of 10 will risk developing
hip dysplasia if both parents are afflicted.
At present, the strongest link to contributing factors other
than genetic predisposition appears to be to rapid growth
and weight gain. In a recent study done in Labrador retrievers
a significant reduction in the development of clinical hip
dysplasia occurred in a group of puppies fed 25% less than
a control group which was allowed to eat free choice. It is
likely that the laxity in the hip joints is aggravated by
the rapid weight gain.
Elbow Dysplasia
Elbow dysplasia is a general term used to identify an inherited
polygenic disease in the elbow of dogs. Elbow dysplasia has
multiple inherited etiologies which may occur singularly or
in combination. These etiologies include fragmented medial
coronoid (FCP) of the ulna, osteochondritis of the medial
humeral condyle and ununited anconeal process (UAP). The most
sensitive view used to diagnose secondary degenerative changes
in the elbow joint is an extreme flexed medio-lateral view
of the elbow which is required by the OFA and recommended
by the International Elbow Working Group. The veterinary radiologists
are most interested in the appearance of the anconeal process
of the ulna.
