OBESITY IN CATS AND DOGS

Obesity in dogs and cats is a serious medical problem. The health risks to overweight dogs and cats are serious and every pet owner should be aware of them. Obese companion animals are predisposed to orthopaedic disease, diabetes mellitus, cardiorespiratory disease, urinary disorders, reproductive disorders, neoplasia (tumours), dermatological diseases, and anaesthetic complications.

HEALTH RISKS WITH OVERWEIGHT PETS
Overall, obesity can have serious detrimental effects on the health and longevity of dogs and cats.
- Diabetes mellitus is one of the most common complications of obesity in dogs and cats. When requirements for insulin (because of excess body fat) exceed the ability of the body to produce insulin, diabetes mellitus develops. If the need for insulin increases over a long period of time, the pancreas becomes insufficient in its production of insulin, again resulting in diabetes.
- Orthopaedic problems occur in a large portion of overweight pets. More than a quarter of overweight dogs develop serious joint complications. If the joints are required to carry excess weight, degenerative joint disease (arthritis) can develop and the pain and changes associated with pre-existing conditions such as hip dysplasia can become markedly more severe.
Extra tension on joints caused by an increased weight load can also lead to damage of certain ligaments. One of the ligaments in the stifle, the cranial cruciate ligament, is very prone to strains or tears.
Certain breeds of dogs, such as Dachshunds and Bassets Hounds are prone to develop intervertebral disc disease. Carrying extra weight increases the probability that they will develop this painful and sometimes debilitating condition.
- The cardiorespiratory function is impaired by overweight. The additional fat in the chest and abdomen restricts the expansion of the lungs. Also the increased quantity of tissue puts an increased demand on the lungs to supply oxygen.
Overweight pets tend to have increased blood pressure. The work load on the heart is increased and this can lead to congestive heart failure.
Dogs and cats that are overweight have less endurance and stamina.
- Heat intolerance is associated with being overweight as fat is an excellent insulator. Pets become much less capable of regulating their body temperature.
- When a dog or cat is overweight, an increased amount of fat builds up in the liver causing hepatic lipidosis. Hepatic lipidosis usually results in decreased liver function.
- Obesity increases the surgical and anaesthetic risks. Many of the anaesthetic drugs and gas are taken up by fat so an overweight animal will take longer to come out of the anaesthesia. In addition, many drugs are broken down by the liver. A fatty liver may not be so efficient at breaking down drugs, so recovery may be delayed.
The increased fat tissue makes the surgery technically more difficult and the procedure will also take longer, which again increases the anaesthetic risk. - Dystocia (difficulty giving birth) is common in overweight animals.
- Intestinal gas and flatulence is a common complaint with overweight dogs, which is not pleasant for the dog or the owner.
- Obesity in the dog has been associated with decreased resistance to viral and bacterial infections. The exact cause of this decreased immune function in obese dogs is unknown.
- Overweight animals sometimes have poor skin and hair qualities. For example, the skin may fold in on itself creating pockets, which are ideal for the accumulation of oils and the development of infections.
- Studies suggest that obese dogs tend to have an increased risk of developing certain types of cancers, including a particular type of cancer of the urinary bladder (transitional cell carcinoma).

For all of the reasons listed above, overweight dogs and cats die at a younger age than those maintained at an optimum weight.

WHAT IS AN OVERWEIGHT PET?
Overweight pets have increased amount of fats over the ribs and minimal or absent waist and tuck-up (the belly area between ribcage and rear end). Obese dogs and cats have heavy fat over the ribs, along the spine, and around the tail. Morbidly fat dogs have protruding abdomen and fat deposits throughout their bodies. Breed characteristics should be taken into account of course, as some breeds have more prominent ribs and tuck-ups when in optimum condition.

WAYS TO CONTROL WEIGHT IN YOUR PET
We are not contributing positively to our pets’ health when we allow them to become overweight. There are ways to prevent obesity.
First assess body’s condition, and bring your pet for a weigh check. If your pet is overweight, have him checked at your veterinary practice and examine both feeding and exercise programs.
Control and prevention of overweight in dogs:
  1. Do not let your dog decide the amount of food he’s getting. An empty bowl does not mean that your dog needs more food. Dogs are scavengers; an empty bowl is often a trigger for pleading or browsing behaviour and does not mean that your dog is starving.
  2. Adapt the fat and calorie content of the food to the needs of your pet. Those needs depend on many factors: the breed (for the same size, a Labrador or a Retriever has lower calorie requirements than a Boxer), the temperament (some dogs are naturally laid back and others are hyperactive and have a higher metabolism), the amount of activity (family dogs only having a gentle walk a day have very low calorie requirements compared to a working gun dog for example), the housing (a dog that sleeps indoors all year long will have lower needs than a dog sleeping outside where he needs to cope with the cold in winter), etc.
  3. Feed appropriate dog snacks and take them into account in the daily ration. Every snack is that much food that needs to be cut back from the next meal.
  4. Watch the supplements used: vegetable oil or cod liver oil adds unnecessary calories to the diet. It is better for the dog to use a food with sufficient omega fatty acids. Also keep in mind that dry coat and itchiness can be caused by allergies or other diseases that have nothing to do with the diet.
  5. If possible, keep your dog away from the table at mealtime, separate him from snacking youngsters, and do no let the kids feed him without supervision.
  6. Provide opportunities for several daily periods of exercise (walks, play times) as well as some prolonged and more strenuous exercise a couple of times a week. Time alone in a yard is not sufficient.
  7. An exercise program should begin with a visit to the veterinarian to assess general health. Short sessions of moderate activity (several short walks a day, daily obedience routine, etc.) are a good way to start, then can be increased gradually as you dog becomes fitter. Overweight and obesity do not happen overnight and cannot be corrected overnight.

It can be more difficult to control the weight of a cat, especially in a multi-cat household. It is difficult to take a cat out for a walk, and restricting food is sometimes impossible if there are several cats in the household, particularly if the cats have quite different body conditions. Yet the basic principles used to control weight in dogs are still true in cats: the aim is to maintain a neutral energy balance, e.g. provide the right amount of calories for the amount of exercise the cat is undertaking.
Control and prevention of overweight in cats:
  1. The first rule for dogs does not apply to cats. Cats get frustrated if their access to food is restricted, and they will compensate by eating even more when they are finally presented with food. Also having fixed feeding times encourages cats to wait for their food and then wolf it down even it exceeds their requirements. That is one of the reasons why it is more difficult to control the weight of a cat on a wet diet because it always implies restricted access to food and fixed meal times. Even if the cat is fed a combination of dry food (available all the time) and wet food (once or twice a day), this will encourage overweight as wet food has so much more appeal to the cat than dry food. Therefore the cat will most likely eat the wet food even though he has already eaten all his daily calorie requirements with dry food. So if your cat is overweight, the easiest way to start controlling his weight is to give up the wet food entirely, and feed him a balanced dry food diet.
  2. Once the cat is entirely on dry food, it becomes easier to control the amount of calories he is getting without restricting his access to food. Measure how much dry food your cat needs daily according to his ideal weight (not his present weight), and give no more that this daily. Give it all in the morning and leave it out for the cat to eat whenever he wants. If you cat finishes before the next morning, too bad for him, he will have just have to be slower the next day, but do not feed him anymore. Once they become used to this method, cats are really good at regulating themselves and nibbling at their food all the way through the day.
  3. Choosing a cat food that is low in calories and higher in fibres gives the cat the impression that, for the same amount of calories, he is eating a bigger volume, so it is a good way to satisfy his hunger.
  4. Encourage exercise is as true in cats as it is in dogs. It is just more difficult to apply to cats. One way to do it if you cat goes outdoor is to encourage him to spend more time outside even he would rather take it easy on the bed… A cat has a furry coat that insulates him really well against the cold (even short-haired cats) so he can go out even on a cold winter day.
  5. Indoors, you can encourage you cat to exercise by providing plenty of toys, and playing with him when you have time. Putting his food in a elevated position forces him to jump to get to the food, so not only will he exercise every time he eats but he will have to consider if he is hungry enough to take that jump! Dividing his daily amount of food in several portions and spreading them around the house will encourage him to hunt for his food. Puzzle toys with food inside are also quite good in that respect.

Finally, whether we are talking about a cat or a dog, it is often the case that pets asking for food are actually seeking attention. Remember that food is not a substitute for attention or a cure for guilt and that firmness can and should be applied to the relationship.
 

LUNGWORM IN DOGS AND CATS

In the UK infection is caused by 3 different lungworms:

1. Angiostrongylus vasorum (dog lungworm)
2. Aelurostrongylus abstrusus (cat lungworm)
3. Crenosoma vulpis (dog lungworm)

The above are widespread throughout the UK with hot spots in certain geographical areas.

Dogs:

Dogs contract A. vasorum by ingesting snails and slugs, infected with the larvae of lungworm. These larvae migrate through the body of the dog ending up in the lungs where they then produce eggs which are coughed up by the dog, swallowed and passed out in the faeces where the lifecycle starts again with ingestion of the eggs by the snails and slugs.

Cats:

A.abstrusus has a similar lifecycle to that of the lungworm in the dog but intermediate hosts are birds and rodents instead of snails and slugs. The presence of adult worms in the airways can provoke an intense inflammatory reaction causing significant respiratory disease.

Clinical Sings in Dogs

Respiratory: coughing
Circulatory: limb swelling, fluid swelling under the skin and within the chest and abdomen
Coagulation abnormalities: bleeding disorders
Neurological: balance problems
General: weight loss, fever, anorexia, collapse

Clinical Signs in Cats

Respiratory signs most commonly:
Coughing, wheezing, difficulty in breathing

Diagnosis

The larvae can be identified in faecal samples

Treatments
1. ‘Advocate’ (Imidacloprid/Moxidectin): ‘spot on treatment’ – treat once and repeat 30 days later
2. ‘Milbemax’ (Milbemycin oxime): tablets – single treatment
3. ‘Panacur’ (fenbendazole): paste/granules – 7 day course

Regular use of the above treatments will act as an effective preventative against lungworm infection.

 
 

TICKS IN DOGS AND CATS

The commonest species found in the U.K. is the hard bodied tick Ixodes ricinus. This is a 3-host tick which means at different stages of its life cycle it seeks to feed from a different host.

Whilst feeding ticks often regurgitate which means that pathogens which they carry may be transmitted to the host. Examples of these are Borreliosis, louping ill virus and the protozoan Babesia species. There is further importance with pets travelling abroad with the Pet Passport scheme as tick borne diseases not present in the U.K. may be passed on.

Dogs in particular which are walked over rough ground are at risk of picking up ticks whose normal host should be sheep or deer. This is especially important in spring and summer. It is much better to prevent this if possible rather than trying to find and remove individual ticks. These can be very small looking like a lentil or small skin tag initially and only become apparent after engagement from feeding. However it is a sensible precaution after walking over this sort of terrain. Special tick removers are available to facilitate this.

Advantix is a very good product which repels as well as kills ticks which often makes them disinclined to attach to feed in the first place. The active ingredient, imidacloprid causes the tick to feel “hot footed” when it travels over treated skin and most will quickly fall off and die.

Although we see far fewer cats with ticks there are a few avid hunters which seem to acquire the odd one. Advantix should not be used on cats and we would recommend the use of Frontline Spray for these animals.

We always stock a comprehensive range of parasite control products suitable for all species, so please ask at the surgery for advice.
 
 

FLEAS

Importance Of veterinary significance not only because of their effects on the animals they infest but as carriers of disease. Though most important in dogs, cats and poultry, their readiness to feed on humans gives fleas a relevance in public health.

Life Cycle
Blood suckers that lay their eggs both on the animal and on the ground. Hatching occurs in two days to two weeks, depending on temperature or the surroundings. The life cycle from egg to adult usually takes place within three weeks but in low temperatures this may extend to two years.

Most of the fleas lifecycle is spent away from the animal. The adult flea can survive as long as six months between feeds. The usual life span is one to two years.

Most fleas feed for only a few minutes before moving to another part of the animal or leaping to the ground in search for another host.

CTENOCEPHALIDES canis (dog flea) and CTENOCEPHALIDES felis (cat flea) occur in the dog and cat respectively but the cat flea is much more widespread and in many cases it is the dominant species on dogs and man, as well as cats. Both dog and cat fleas act as intermediate hosts of the dog and cat tapeworm Dipylidium caninum.

Pathogenic Significance
The response to a flea bite is a raised, slightly inflamed wheal on the skin, associated with mild itching. After repeated flea bites over a period of several months a proportion of dogs and cats can develop flea-bite allergy which is often associated with profound clinical signs.

Flea-bite allergy is a hypersensitivity reaction to the flea saliva released into the skin during feeding. The resulting allergy shows a seasonality in temperate areas, appearing in summer when flea activity is highest, although problems are also seen all year round in centrally heated homes.

Most commonly affected areas in dogs and cats are the preferential biting sites of the fleas which are the BACK, LOWER ABDOMEN and INNER THIGHS. In the dog the primary lesions are discrete crusted spots which cause intense itching. The secondary damage, however, is done by the animals themselves as they scratch and bite affected areas. This produces areas of hair loss or of moist dermatitis (""wet eczema""). In older dogs which have been exposed for many years the skin may become thickened, folded and hairless, in these animals itchiness is much less intense.

In the cat flea-bite allergy produces a condition commonly known as miliary dermatitis, or eczema, readily detectable on palpation as skin is covered with innumerable small, brown, crusty spots which caused marked itching.

Treatment and Control
Pets themselves : Several new insecticides are now available in spray and spot-on treatments (eg. FRONTLINE and ADVANTAGE), some of which give two to three months protection with a single application. In addition there are oral and in-feed formulations that are very effective in preventing infestations eg. PROGRAM.

Environment : Since the greater part of the flea population is not on the animal itself but in it's environment, it is important that inseciticides are also applied to the living quarters, general indoor habitat and bedding should be destroyed where possible. If animals are commonly transported in the car this may also require treatment. Products are available now, that when applied to the environment, can prevent flea development for twelve months eg. ACCLAIM spray.

Any of our staff will be more than happy to answer your queries in person or by e-mail.
 
 

MYXOMATOSIS

What causes myxomatosis? The disease myxomatosis is caused by a virus. The virus is a type of pox virus which grow best in the skin of rabbits. What are the signs of myxomatosis? The very first signs seen are puffy, fluid swellings around the head and face. 'Sleepy eyes' are a classic sign along with swollen lips, tiny swellings on the inside of the ear and puffy swellings around the anus and genitalia. Within a day or so, these swellings can become so severe as to cause blindness and there may be some distortion around the face, mouth, ears and nose. How is the disease spread? Myxomatosis is spread by blood sucking insects. A major insect parasite which transmits the disease in this country is the rabbit flea which is frequently found on wild rabbits although is less common on pet rabbits. There is strong circumstantial evidence that mosquitoes and related insects e.g. midges transmit myxomatosis in the UK. The virus can remain alive in the blood of fleas for many months and the over - wintering of fleas in rabbit burrows is probably the means by which the disease is transmitted from year to year. After infection how long do rabbits usually survive? This varies. Some animals may survive for weeks or months after infection but in general, if an infection is severe in a susceptible rabbit, death occurs within 12 days. Prevention Vaccination : an effective vaccine is available. A single injection is given any time from 6 weeks of age. This will give protection for at least 6 months. We recommend that vaccination is done at the beginning of April to give maximum protection over summer and autumn, the period where biting insects are most prevalent. Please contact the surgery to arrange an appointment in good time.
 
 

FARM NEWS

The Treatment and Control of Fluke in Sheep and Cattle The Disease: The number of outbreaks of disease caused by liver fluke in cattle and sheep in Scotland has increased dramatically in recent years. The disease poses a threat to animal welfare and may also cause economic losses through mortality, ill – thrift, condemnation of livers at the abattoir, predisposition to other diseases, treatment and associated costs.

The risk of liver fluke is closely linked to summer rainfall, which favours fluke development and provides an optimum habitat for the intermediate host, the dwarf pond snail (Lymnaea trunculta). The disease has been long associated with high mortality in sheep flocks and anaemia with poor production in beef and dairy cattle. In the past few years, fluke related deaths have also been reported in adult cattle.

The Life Cycle: see diagram Fluke eggs are passed in dung of sheep/cattle develop and hatch into larvae (called miracidia). This takes 9 days at optimal temperature of 22 – 26 degrees Celsius. Development at lower temperatures takes longer and will not occur below 10 degrees. The larvae must come into contact with their intermediate host within 3 hours of hatching from eggs for the snails to become infected. The larvae develop inside the snails to become final larval stages called Cercaria. These are then shed from the snails and attach themselves to firm surfaces e.g. grass blades. They then go through one more change (to metacercaria) which makes them infective to cattle and sheep. It takes at least 6 to 7 weeks from the hatching of the fluke egg to the infective metacercaria. A snail will produce 600 infective metacercaria for every single miracidia that infects a snail. Once eaten by the final host the infective larvae migrate through the gut wall, cross the peritoneum and penetrate the liver capsule. The young fluke tunnel through the liver tissue for 6 to 8 weeks before entering the small bile ducts where they mature in about 4 weeks; as they get bigger they move to larger bile ducts and occasionally to the gall bladder. It takes approximately 3 months from ingestion of the infective larvae by cattle / sheep to fluke eggs being passed out of the animal in dung. The whole life cycle take 4 to 5 months to complete.

Epidemiology: Climate and soil conditions affect the habitat of the dwarf pond snail. Ideal conditions for the snails are : Slightly acidic environments Slow moving water medium to carry away waste products Permanent habitats therefore include banks of ditches or streams and the edges of small ponds. Following heavy rainfall / flooding, temporary habitats may be provided by hoof marks, wheel ruts or rain ponds. Fields with clumps of rushes are common sites as these have slightly acidic PH. Summer rainfall is the main factor in encouraging snail and fluke populations. The majority of snails are therefore infected in SUMMER from eggs deposited in SPRING and EARLY SUMMER. The snails are shedding the infective larvae (metacercarea) from LATE AUGUST onwards. Clinical disease in sheep and cattle normally occurs from SEPTEMBER onwards. Some fluke outbreaks have however, continued from WINTER into the SPRING and SUMMER where mild, wet conditions have occurred over Winter which have favoured the out-wintering of fluke eggs and larvae. Clinical Signs: SHEEP Acute: • Seen LATE AUTUMN and EARLY WINTER (in wet years can extend to SPRING) • Associated with large numbers of immature fluke in the liver tissue. • Associated with ingestion of large numbers of infective larvae over a short period from heavily infected pasture. • Associated with prolonged migration of fluke in sheep previously exposed to the parasite. Sudden death caused by acute haemorrhagic anaemia Remainder of flock may be weak, pale with signs of abdominal pain Sub-acute: LATE AUTUMN to SPRING • Acute haemorrhagic anaemia with rapid loss of condition and death in 1 to 2 weeks. • Fluid swellings under the jaw (bottle jaw) may occur. Chronic: WINTER to SPRING • Weight loss and anaemia occurs, caused by blood sucking activities of adult flukes in the bile ducts. In severe cases bottle jaw and terminal diarrhoea can occur. CATTLE Acute: can occur rarely causing sudden death. Chronic: as for sheep but may only show as lowered productivity: • inadequate food conversion rates • poor carcass formation • reduced milk yields (solids not fats) in high yielding dairy cows • may precipitate metabolic disease around calving. Only a few fluke causing damage in the liver can predispose to death by secondary Clostridial diseases

DIAGNOSIS - Post Mortem identification of fluke in the liver - Fluke Egg Counts. Done in Spring. Only of help in chronic disease i.e. adult fluke. - Liver enzymes are increased when liver damage has occurred. - Blood test for eosinophilia – useful in adult cattle and as early indicator of fluke presence in dairy herds where metabolic disease was initially suspected Sheep never become immune to fluke infection. Cattle do develop a degree of resistance, partly due to the presence of more fibrous tissue in the liver which limits damage by the immature fluke.

TREATMENT and CONTROL -reduce snail population -eliminate fluke from animals -drainage of snail habitats – costs usually prohibitive -localised wet areas can be fenced off. FLUKICIDES Acute disease can occur from August to May so MUST kill IMMATURE fluke. Some resistance has been found to triclabendazole flukicides. If resistance suspected check for fluke eggs three weeks after treatment and if present use different flukicide. Quarantine: New cattle : treat with a flukicide effective against immature fluke and then keep off snail contaminated pastures for 4 weeks. If fluke present on farm dose animals with flukicide with activity against immature fluke – dose in OCTOBER and a further dose in January if faecal egg counts indicate a need. A flukicide with Adult only activity should be given to all at risk animals in MAY/JUNE. The same flukicide should not be used year after year for autumn/winter treatments. Note Deer and rabbits act as fluke reservoirs so fluke eradication is not possible where the snail habitat exists.
 
   
 

Glenythan Vet Group 2007.

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