Experienced and professional animal trainer provide their insights in answering this question :
A. If this is a dog they need medical attention asap so that they don’t starve. There may be nerve problems that prevent the mouth from being able to chew.

How to Identify Common Pet Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced pet care professionals :

Surgery, drug reactions, stress, heart disease, and other issues may also cause weight loss in canines. If your dog is refusing to eat, losing weight, or has any other digestive or feeding issues, play it safe and let the veterinarian take a look at your pet.
Weight loss in dogs is the result of a calorie deficit. This may be caused by high energy demands, poor quality food, or a number of health issues. A sudden weight loss can be caused by many different diseases including dental problems, intestinal parasites, diabetes, and cancer.
Changes in diet (not including restricted-calorie foods), environment, or stress levels, including the addition of new pets, may lead to weight loss that is rarely permanent or significant. The more rapid the weight loss, the more potentially concerning it is.
A dog who loses weight but still seems to be eating and drinking as much as before might need a visit to the veterinarian, too. “They`re not taking in enough calories to support themselves,” says Shawn Finch, DVM, with Gentle Doctor Animal Hospitals in Omaha, Neb.
Some of the signs of parvovirus include lethargy; loss of appetite; abdominal pain and bloating; fever or low body temperature (hypothermia); vomiting; and severe, often bloody, diarrhea. Persistent vomiting and diarrhea can cause rapid dehydration, and damage to the intestines and immune system can cause septic shock.
Losing weight – Some worms eat the food our dogs consume. This means dogs can lose weight even if they`re eating more, because some of the food is feeding the worms inside them.
Being able to feel your dog`s spine is a good thing. When running your hands over your dog`s back, you should be able to feel the bones, but they shouldn`t be protruding. Depending upon how your dog`s spine feels, the issue may be weight-related.
Signs of heartworm disease may include a mild persistent cough, reluctance to exercise, fatigue after moderate activity, decreased appetite, and weight loss. As heartworm disease progresses, pets may develop heart failure and the appearance of a swollen belly due to excess fluid in the abdomen.
Weight loss can be a sign your dog is suffering from one of many possible gastro-intestinal disorders, which can affect their stomach and intestines. Other signs to look out for are chronic diarrhea or constipation, vomiting, dehydration and lethargy.
Dogs can spread parasites without any signs of infection. If symptoms do appear, you may see: loose stool; diarrhea; blood in the stool; weight loss; an inability to gain weight; a dull, coarse coat; or in some cases, worms visible in the feces.
Signs that a dog has liver disease can vary and include loss of appetite, vomiting, stomach ulceration, diarrhea, seizures or other neurologic problems, fever, blood clotting problems, jaundice (a yellow tinge noticeable in the skin, mucous membranes, and eyes), fluid collection in the abdomen, excessive urination and …
Parvo smell has a unique very bad-smelling poop that is not easy to forget. The smell has been described as metallic, with hints of blood stench since the virus affects the intestinal walls, and a seemingly sweet scent.
The scent generally associated with parvo is caused by blood in the stool. Dogs with bloody stools because of hookworms have precisely the same smell. MORE IMPORTANTLY, if a puppy is diagnosed with Parvo BEFORE there is blood in the stool, the antivirals` effectiveness is MUCH GREATER.
Tapeworm infections are usually diagnosed by finding segments—which appear as small white worms that may look like grains of rice or seeds—on the rear end of your dog, in your dog`s feces, or where your dog lives and sleeps.
Symptoms may include diarrhoea, tiredness and weakness, abdominal pain and weight loss. Some worms cause anaemia.
Roundworms* and hookworms develop from eggs into larvae (immature worms). The larvae later grow into adult worms. Most pets show no signs of infection with these worms, but some may vomit, stop eating their food, or lose weight.
Dogs that are infected often lose their appetite or, in some cases, have a sudden increase in hunger. Even though your dog may have increased appetite levels, he may still lose weight. As with the other symptoms of worm infestation in dogs, you should visit a veterinarian as soon as your dog shows changes in appetite.
Are these infections serious for dogs? Intestinal worms can be a serious problem in young puppies. Hookworms can cause anemia and roundworms can lead to poor growth and development. In adult dogs, however, intestinal parasites are only occasionally life-threatening.
Allergies, hormonal imbalances, fungus, parasites and localized inflammation can lead to an overgrowth of yeast or bacteria on the skin and cause an unpleasant smell.
Addison`s disease in dogs (also called hypoadrenocorticism) occurs when your dog`s adrenal glands aren`t producing adequate levels of corticosteroid hormones. If diagnosed and treated appropriately these dogs can live a long, happy life. The adrenal glands are two small glands next to the kidneys.
In dogs, the metabolic syndrome is well recognized in experimental conditions, where the obesity is induced by excessive administration of fat rich diets. The syndrome is associated with the development of atherosclerotic disease, lipodystrophy, abnormal hematological and blood coagulation.
If you notice changes to your dog`s backbone, such as vertebrae suddenly appearing more apparent, this may indicate a health concern. Muscle wasting, nutritional issues, metabolic disorders, certain types of cancers, and osteoarthritis in dogs can all make the backbone more visible.
It is suggested that dogs mildly to moderately underweight be provided with a diet moderately high in fat and protein. These diets should have adequate levels of carbohydrates but not predominantly carbohydrate. Try to feed products that show (for dry food) fat content of 18% and protein 28-30%.
Many dogs with CHF will tire out more easily, have reduced stamina, and do not engage in playing or walking as they once did. Coughing when at rest or sleeping, excessive panting, persistent loss of appetite, a swollen belly, and pale or bluish gums are also signs associated with heart failure.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Q. How do I determine how much my overweight pet should weigh?
ANSWER : A. There are many tools to determine overweight and obesity levels in pets. A new tool, morphometric measurements and body fat index, are available to accurately determine a pet’s ideal weight; this will allow an accurate determination of the amount of food a pet should receive to achieve weight loss. Feeding the correct amount will lead to greater weight loss success.

There are many weight loss food options to help pets reach their ideal weight. Your veterinarian can help make a ideal weight recommendation. Here are some tips to help your dog lose weight in a healthy and safe way:

1. Diet: Providing a healthy and well balanced diet is essential to your pet’s overall health. Finding the right food for your dog can be a challenging process. For those overweight animals many commercial dog companies offer weight loss diets, but it is important to evaluate food labels for adequate nutritional content.

You want to ensure you are not missing other essential vitamin or mineral content. Volume of food is also important and the amount of food that works for one breed of dog may not be the same for another breed of dog. Portion control as opposed to free-choice feeding can help your dog to drop a few unnecessary pounds.

There are also prescription weight loss foods designed by veterinary nutritionists, such as Hill’s r/d (http://bit.ly/1AoENSd). Some pet owners find that home cooking is the best option for helping to provide a well-balanced and realistic diet plan. There are websites such as balanceit.com that offers recipes to fit your dog’s specific needs. Consulting with your veterinarian or a veterinary nutritionist to find the appropriate diet is a great way to help your dog be as healthy as possible.

2. Exercise: Another great tactic for weight loss for your dog is exercise. Whether this is through running, walking or playing with a favorite toy all of these are wonderful types of exercise to help keep your dog at a lean and healthy weight.

For those pet owners with busy schedules utilizing professional dog walking services or playtime through dog daycare services is another option. It has been shown that those pet owners that exercise regularly with their pets generally live a healthier lifestyle.

3. Physical therapy: As animals age pet owners offer encounter their favorite canine having more difficulty walking and have a dwindling desire to play with toys. Physical therapy, specifically hydrotherapy is a wonderful way to help older and arthritic animals gain more mobility and lose weight. Hydrotherapy has been proven to have several therapeutic effects on the body including, muscle strengthening, relief of swelling, decreased joint pain, less stiffness in limbs, improved circulation, weight loss, and increased tissue healing to name a few. For more information on the benefits of hydrotherapy:
http://bit.ly/1w1qqoy

4. Veterinary visit and blood work: Weight gain can also be related to underlying health concerns such as hypothyroidism or other endocrine disorders. Scheduling a veterinary evaluation and routine blood work can be another important component in increasing the longevity of your dog’s life. Conditions such as hypothyroidism that predispose dogs to gain weight can be treated with a daily medication to improve hormonal balance. If feel that your dog is unnecessarily overweight there can be an underlying health condition that needs to be addressed.

5. Healthy treats: Pet owners love the chance to reward their favorite canine companion with treats and most dogs jump at the chance to consume these delicious products. The problem is many treats, which can include commercial dog treats or table scrapes can add many unnecessary calories to your dog’s daily intake. Reading labels and making note of the calories in these treats is an important component of understanding your dog’s overall health. Treats should not exceed more than 10 percent of your pet’s daily calories. There are healthier treats that can be offered to your pet to keep calories lower yet provide a fuller sensation. A pet owner can add steamed or pureed vegetables, such as carrots, green beans or sweet potato to add more fiber and thus a fuller feeling for your dog.

Q. How do I know if my pet is overweight?
ANSWER : A. There are many ways to determine if your pet is overweight: breed standards, body condition score (BCS), body fat index (BFI), and morphometric measurements. These tools are used to determine how overweight a pet is, as well as to determine how much to feed to reach the pet’s ideal weight. Most weight loss programs fail because food dose calculations are based on inaccurate estimations of ideal body weight.

Current methods of estimating ideal body weight (body condition score/ guessing) are most likely to underestimate % body fat and therefore overestimate ideal weight, which leads to overfeeding. Pets are being overdosed on food because of inaccurate estimations of ideal body weight.

To determine body condition score it’s often helpful to have a scale from 1-5 to compare to: http://www.hillspet.com/weight-management/pet-weight-score.html. This scale is based on your ability to feel or see the ribs, the size of your dog or cat’s waist, and the appearance of the abdomen.

An overweight animal can be predisposed to several health conditions including high blood pressure, arthritis, endocrine disorders such as diabetes, and hypothyroidism. This is why it is important to determine an ideal weight for your pet and work hard to maintain a healthy weight.

Q. My 16 year old indoor cat has lost most of her body weight in the last couple of weeks. I think she may have worms. What do I do?
ANSWER : A. Weight loss can be a serious sign of many underlying conditions in older cats, most notably metabolic issues such as thyroid disease or organ dysfunction. If no worms are visible in her stool, bringing in a stool sample to check for them, or making a wellness exam to check for any other causes of the weight loss are best to help find why your cat is losing weight prior to just treating for worms.

If worms are present, then determining the type of worms they are is the next step. Worms generally cause digestive upset in cats such as vomiting or loose stools in addition to weight loss in large infections. The two most common types include roundworms (long spaghetti-like strands) and tapeworms (small rice grain segments). Roundworms can generally be cured with any over the counter wormer, however tapeworms need a wormer specific to them to be given. Tapeworms are also spread via contact with fleas, so starting a flea prevention treatment can help prevent further infections. Cleaning all bedding and the environment your cat is in will also help for any type of internal parasite infection.

Q. My pet shows weight loss and has a hard time walking, like he has lost strength in his legs and has no control to maintain balance. What’s wrong?
ANSWER : A. Loss of balance or inability to control the limbs can be caused by a wide range of problems and is usually cause for concern. Damage to the nerves or muscles can cause loss of balance, as well as neurological disease or some illnesses. Having your vet perform a complete examination is needed to determine the exact cause.

Weight loss can refer to the actual loss of fat and weight on your dog, or may also be due to the loss of muscle tone in the body. If there is a problem with one of the limbs, it may be that the weight loss you are seeing is actually loss of muscle in that area. Weight loss can again be caused by a wide range of problems from neurologic disease, illness, parasites or disease. Making an appointment with your vet is best.

Q. Lost weight can’t close mouth, not hungry,
ANSWER : A. If this is a dog they need medical attention asap so that they don’t starve. There may be nerve problems that prevent the mouth from being able to chew.

Q. What should a Papillon weigh that is 11 inches at the shoulder?
ANSWER : A. Per AKC breed standard, there is no set weight for the Papillon. The only guideline given is that weight should be proportionate to height. In general, females may weigh a bit less than males; yet in regard to height both genders will fall between the 8 to 11 inch guideline.

In general, if a Papillon is of standard height, the adult weight will be between 6 pounds (2.72 kg) to 10 pounds (4.53 kg). It is not uncommon for a female to be a bit smaller than a male in regard to weight. Females tend to settle down near the 6 to 8 pound range and males generally are a bit larger and are closer to the 9 or 10 pound range.

We have seen some sources list the weight of the Papillon to be as tiny as 4 pounds (1.81 kg) however this is not common and a Pappy of this size would be considered undersized should he or she be the expected 8 to 11 inches tall (floor to withers).

So, with this information, your dog should weigh about ten pounds if she is 11 inches at the shoulder.

Q. My dog has gone from 6 lbs to 10 lbs in in 2 mos. Due to lo thyroid it was 1 2.1 1.2 she has not lost any weight What do you think Shes on med
ANSWER : A. Your question seems to have got so it is difficult to give specific advice. Weight loss and especially a halt to further weight gain would be expected as thyroid medication starts to work but weight is also related to calorie intake and exercise so a combination of all three is required in order to manage successfully. A repeat blood should be taken to assess current thyroid levels, she may need her dose altering. A metabolic/weight loss diet may also be required alongside exercise

Q. My Chihuahua is 8 years old and has only had 3 legs since birth and her mother chewed one off. She needs to lose weight and I have tried everything
ANSWER : A. There are specific weight loss/metabolic diets which are very successful in encouraging weight loss if fed to recommended guidelines, whilst still allowing her to feel full and satisfied. It would be helpful to make sure she has no sponsors in the household or neighbors which are limiting her progress in her diet. An appointment with a physiotherapist may be able to outline some exercises suitable for her mobility and current weight and feeding her through a treat ball to encourage activity may also help if she is reluctant or unable to go walking. It is possible there may also be a medical condition such as Cushing or thyroid disease contributing to her weight gain/unsuccessful dieting also and blood tests would be recommended to investigate this alongside other measures of calorie reduction, improved metabolism and an exercise plan.