BY: BRUCE LAWHORN, DVM, MS
Any feeding strategy for the pbp should furnish adequate nutrition by a balanced ration and prevent excess weight gain. Although sizes and weights of mature pbps may vary greatly, generally speaking, the heaviest mature weight for even the largest frame pbp of today should not exceed about 125-150 pounds. Of course, there are many small frame pbps today compared to a decade ago. The feeding goal is the same no matter what the frame size. So what is obese? When a pbp is so heavy that walking is difficult, the eyelids are forced closed by facial fat and the tailhead is buried in its behind, this is obvious obesity. I generally think that an additional 25 pounds is considered overweight or fat. Greater than this is obesity. I have seen some pbps that are 125-150 pounds heavier than their frame size will allow. This is insane obesity. It is a miracle that these pbps can walk around, and many can’t.
It is too late for the owner to be sorry for all the medical problems their obese pbp has suffered once an illness crisis arises. The most skilled pbp veterinarian may not be able to remedy the situation. Why is this?
Other than the animal description and problem history, making a diagnosis in the sick, obese pbp is extremely challenging. The physical exam, which includes temperature, pulse and respiration is probably the easiest to evaluate but the slightest exertion increases the temperature and causes the pulse and respiration to race due to the excessive weight burden.
Evaluating the color of the mucus membranes, capillary fill-time and pupillary response are more difficult because access to the oral cavity and orbit is reduced. The so-called entropion seen in obese pbps should be re-evaluated after weight loss which may make the condition disappear.
Collection of body fluids for diagnostic tests is even more difficult. This includes blood sampling and intravenous therapy. Cut downs through the skin to access veins may have to be performed. Even routine blood draws from the cranial vena cava (lower neck area) are challenging since all the anatomic landmarks are obscured by fat deposits.
Values for routine serum enzymes and complete blood counts require good blood sample quality and may be distorted as the degree of difficulty in obtaining samples increases. For example, pig blood rapidly clots and is easily hemolyzed (red blood cells easily ruptured). Hence, these diagnostic tests become harder to interpret.
Urine collection in the obese male is difficult because the abdomen drags the ground. Midstream catch samples of urine from the female is somewhat easier but woe unto the veterinarian if catheterization of the urethra is necessary. An endoscope (which many veterinarians do not have easy access to) is required to visualize the urethral recess since the massive amount of fat collapses all normal anatomic structures and makes blind passage of a catheter difficult to impossible.
If all this were not enough, ultrasound and radiographs are hindered by the extreme thickness of the body walls.
Any type of anesthesia puts the obese potbellied pig at high risk due to its inherent small chest and lung capacity. Many veterinarians use face masks to induce and maintain gas anesthesia because pigs in general are hard to intubate and irritation from repeated attempts at intubation may cause throat swelling and reduced air movement after surgery. The time required to situate an endotrachael tube into an obese pbp is increased due to reduced visibility from compression of the oral cavity by fat. An oral speculum and endoscope may even be necessary.
Obese pbps are also at higher risk for fatal post surgical complications such as heart, kidney or multi-organ failure. Veterinarians do not know all the reasons for this higher risk, but a leaner pbp would be much less of an anesthetic risk. Embolism and death has occurred post surgically from orthopedic procedures in the normal weight pbp: the risk may be higher for the obese patient.
Both kidney failure, a common cause of death in geriatric pbps, and lameness are probably accelerated by obesity.
So you see, these are many, many medical reasons to keep your pig fit and trim!