Weight-conscious people are familiar with BMI (Body Mass Index) as a yardstick to identify ideal weight in humans. Pet owners are also focused on the weight of their pets. Luckily, there is a way to measure the body condition of our furry friends, too. The pet version of BMI is called BCS (Body Condition Score) and it is a quantitative, yet subjective, method for evaluating body fat. It may seem more complicated than the human scale because, although people come in lots of different shapes and sizes, the pet world has a bigger variety of both—especially the canine portion of the pet population. Think: Chihuahua vs. Bulldog vs. Great Dane.
Despite the variety of body types in dogs and cats, there is an organized system of evaluating BCS. Two recognized BCS scales are utilized, one ranging from 1-5 and the other from 1-9. Some veterinarians prefer the 1-9 scale, which has more latitude to identify subtle changes in weight. Others like the 1-5 scale, which has fewer categories. Whatever method you choose, it is best to identify the scale by referencing the highest number. For example a dog with a BCS of 5 would be obese on the 5 point scale (5/5) and ideal weight on the 9 point scale (5/9). A cat with a BCS of 3 would be ideal weight on the 5 point scale (3/5) and thin on the 9 point scale (3/9). Reference points are therefore important.
Here is how the numbers stack up for both scales:
Assigning a Score
Assigning a score to your pet requires visualization and palpation. You have to look at and feel your pet. Start by looking at your cat or dog from above. Does she have a waistline that curves in behind the rib cage giving her an hourglass figure? Next, sit on the floor and look at your pet from the side. Does he have a tummy tuck? Does his abdomen slant upwards between the ribcage and the hind legs? Or does he have a saggy belly?
"If your pet is a healthy weight, you should easily feel his ribs."
Now for palpation. If your pet is a healthy weight, you should easily feel his ribs. Place your thumbs on the backbone and spread your fingers across his rib cage. You should feel a thin layer of fat with the ribs right underneath. A good comparison is feeling the knuckles of your hand: too thin is the feeling of the knuckles with your hand closed in a fist; too much fat is the feel of your knuckles on the underside or palm side of your hand; and ideal is feeling the knuckles when your hand is resting on a flat surface.
A pet with a BCS of 3/5 or 4-5/9 will have ribs that are easy to palpate without applying any pressure with your fingers. An emaciated pet with a BCS of 1/5 or 1/9 will have ribs that stick out with no fat layer. These ribs are not only easy to feel but are easy to see. Obese pets with a BCS of 5/5 or 9/9 have ribs covered by a thick layer of fat making them very difficult to see or feel. You can also run your hands over your pet’s rump to feel the pelvic bones. And pet him from neck to tail to feel the backbone. Both areas should be covered with minimal fat allowing you to actually feel bone without pressing too hard.
Now, assign a numerical score to what you see and feel.
1/5 or 1/9 Ribs, backbone, pelvic bones stick out. Loss of muscle mass present. Severe tummy tuck and dramatic waistline on both cats and dogs. 1.5/5 or 2/9 Ribs and backbone and pelvic bones visible, but only minor loss of muscle mass. Severe waistline and tummy tuck. 2/5 or 3/9 Ribs, pelvis, backbone easily palpated and somewhat visible. Severe waistline and tummy tuck. 2.5/5 or 4/9 Ribs, pelvis, backbone easily palpated but not as visible. Obvious waistline and tummy tuck. 3/5 or 5/9 Ribs, pelvis and backbone palpable with a thin layer of fat covering. Waistline and tummy tuck obvious but not severe with more gradual curves. Cats have minimal abdominal fat pad in front of the rear legs. 3.5/5 or 6/9 Slight fat layer over ribs, backbone and pelvis making them more difficult to palpate. Tummy tuck present but minimal. Waistline visible, but not prominent. Cats have minimal fat pad. 4/5 or 7/9 Ribs covered with heavy fat layer requiring finger pressure to feel. Difficult to feel backbone or pelvis. Waistline not apparent. Tummy tuck still slightly visible. Cats have moderate abdominal fat pad. 4.5/5 or 8/9 Ribs, pelvis and backbone covered with thick fat layer and palpable only with extreme pressure. No tummy tuck or waistline. 5/5 or 9/9 Ribs and backbone not palpable under thick fat layer. Abdominal distention projects downward (opposite of tummy tuck) and outward (protruding waistline). Fat deposits on legs, face and over tail head covering pelvis. Cats have extensive abdominal fat pad and sagging bellies. Note: Feeling ribs is less disturbing to the dog than feeling the backbone or pelvis. Arthritic dogs may experience pain if you press on their back or hips.
BCS and Pounds
Determining when a pet has reached an ideal body weight takes into consideration both BCS and actual weight. When monitoring a weight program, it is important to record both numbers simultaneously. Get into the habit of weighing your pet each time his BCS is assessed and keep an ongoing record to track progress. To compare your pet’s score with your own, remember that a BCS of 4/5 or 7/9 correlates to 30% body fat, which is considered overweight in people
The State of Pet Obesity
In 2017, the Association for Pet Obesity estimated that 56% of dogs and 60% of cats in the United States were overweight. That means the majority of cats and dogs need to shed a few pounds. As with humans, pet obesity has serious health implications. Heavy pets are at greater risk for heart disease, diabetes, joint ailments (arthritis), high blood pressure, and surgical/anesthetic complications. Moreover, overweight pets have shorter life spans than their fit colleagues, as seen in the Purina Life Span study. In this study, dogs at ideal body weight lived approximately two years longer than their obese counterparts.
"The Association for Pet Obesity estimates that 54% of pets in the United States are overweight."
Keeping your pet fit will make his life happier, healthier, and longer. Sadly, obesity is the number one nutritional disorder of pets. Luckily, it is one that we can manage and monitor by utilizing systems like BCS.
Written by: Krista Williams, BSc, DVM, CCRP; Lynn Buzhardt, DVM Credit to: VCA Animal Hospital