Dan was a nine year old Springer Spaniel who loved strenuous physical exercise. His owner, Dr Mullen, was a medical doctor who was an enthusiastic hill walker, so they made a good team. They would spend days off in the Dublin mountains together on six-hour hikes through the countryside. Dan was brought to see me because he had developed an irritating cough, and Dr Mullen was worried.
The cough did not affect Dan during exercise. He was still able to run for hours without any problem, but the following morning, immediately after getting up, he would cough repeatedly as he walked around the room. It seemed to be a productive cough: sometimes he swallowed after the cough, and other times Dr Mullen found patches of white phlegm on the floor. When Dan had been up and about for half an hour, the cough seemed to clear, and he’d be fine for the rest of the day.
I started by physically examining Dan. I listened carefully to his chest with my stethoscope. He had the perfect heartbeat of a fit dog, with slow steady sounds and no murmurs or irregularities. His lungs, however, sounded noisier than normal, with some wheezes and crackles. He definitely had some type of lung disease, and further tests were needed.
The following day, Dan was anaesthetised, X-rays were taken, an endoscope was used to directly view the lining of his airways, and finally tiny biopsies were taken of the many red sore areas that we could see. Dr Mullen called in three days later to discuss the full results of our investigations.
“I can say for certain that Dan is suffering from Chronic Bronchitis”, I began. “The initial X-rays suggested that that there was thickening of his lower airways, and using the endoscope, we could see that the thickening was because of inflammation of the lining of the small tubes of the lungs, known as ‘bronchi’. The biopsy of the red, swollen areas confirms that the disease process is simple inflammation, with nothing sinister going on. Finally, he has a mild bacterial infection in his lungs.”
Dr Mullen asked me if an antibiotic would completely cure his dog.
“Although antibiotics will help him, for a complete cure, he needs to go onto long term medication using other drugs. The chronic bronchitis probably started out with a simple infection, but there is now also an irritant and allergic aspect to the disease. The tiny particles of dust, smoke and pollens that are always in the air are perpetuating the bronchitis. We’ll use two drugs to help him. Firstly, a ‘broncho-dilator’, which will widen his airways and lessen the tight narrowing of the bronchi that is making them irritated. Secondly, a low dose of steroids will directly lessen the irritation. We’ll modify his dose of each drug so that he should be able to live a normal, symptom free life without side effects from medication.” There are other options for treatment, including an inhaler mask, but this treatment was my standard first stage.
Dan was sent home with three containers of tablets, and twice-daily medication ritual became part of his routine. I saw him again two weeks later, and the cough had almost completely stopped. He was suffering some side effects from the steroids, with increased thirst and appetite, but we were then able to reduce the dosage, so that he was given tablets only on every second day. When he came back a full month later, Dr Mullen was delighted.
“His cough has vanished completely”, he told me. “And he is enjoying his walks more than ever. The only problem is that he’s wearing me out! Do you know any tonic pills for a fifty-five year old human?”
There's one aspect of nutrition that many people – including vets – can find particularly daunting: fats and oils. There have been mixed messages over the years about good fats/ bad fats, essential oils/ unnecessary oils, long chain/short chain, saturated/unsaturated. This is one area where Wikivet can help – for veterinary professionals as well as members of the public. The Wikivet section about fatty acids provides a clear, comprehensive summary.
The most important facts are worth summarising in ten key points:
1) The terms “fats” and “oils” tend to be replaced by “fatty acids” by nutritionists, as it is the fatty acids in fats and oils that give them their most significant properties.
2) Fatty acids (FA) are carboxylic acids with long hydrocarbon chains, which can be saturated or unsaturated.
3) Saturated fatty acids have single bonds, and tend to have a high melting point making them more likely to be solid at room temperature (e.g. butter or fat on meat)
4) Unsaturated fatty acids have at least one double bond, and tend to have a low melting point so tend to be liquid at room temperature (e.g. olive oil)
5) Mammals are able to synthesize certain saturated fatty acids from other dietary components (such as glucose and proteins) so they do not need to have these in the diet.
6) Dogs and cats, like other mammals, have an essential dietary requirement for certain unsaturated fatty acids since they cannot be manufactured in their bodies: omega-3 and omega-6: these are known as "essential fatty acids".
7) (A technical point, but an important one for biochemistry nerds): Omega-3 FAs are a family of unsaturated fatty acids that have a double bond in the third carbon-carbon bond: the most important are Alpha-linolenic acid (ALA), Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)
8) Omega-6 FAs are a family of unsaturated fatty acids that have a double bond in the sixth carbon-carbon bond: e.g. linoleic acid (LA) is an essential ingredient in animal diets. Others in the group include Gamma linolenic acid (GLA), Dihomo-gamma-linolenic acid (DGLA) and Arachidonic acid (AA) (which is essential for cats, but not for dogs).
9) Omega-3 and omega-6 fatty acids are in competition for the same metabolic enzymes in the body and the ratio of omega-6 to omega-3 fatty acids, as well as the total amount of each type, is important.
10) (The key take home point!) These essential unsaturated fatty acids are important for growth (including the development of the brain and eyes), for skin and coat function (including influencing allergic skin disease)
First, choose a good quality diet that is adequately supplemented with the right proportions of omega-3 and omega-6 unsaturated fatty acids.The optimal ratio of omega-6 to omega-3 fatty acids is thought to be between 10:1 to 5:1. Most pet foods contain far more omega-6 fatty acids than omega-3. Omega-3 fatty acids are sometimes added to commercial pet foods to lower the ratio of omega-6 to omega-3 fatty acids.
Second, if your pet suffers from skin disease, in particular, or poor skin/coat quality, talk to your vet about dietary supplements to enhance their omega-3 and omega-6 intake, aiming to get both the absolute quantity and the ratio correct.
Third, remember that it takes around six weeks for a dietary supplement of fatty acids to make a visible difference to the quality of a pet's coat.
Fourth and finally, if you have a good head for understanding chemistry and nutrition, go ahead and read the Wikivet article, and better again, look up the references at the end. This is pure nutritional science, as good as you can get, and it's what pet food companies use to formulate the products on the shop shelves. It may be hard to follow sometimes, but the best way to optimal nutrition is to fully understand the science behind what you feed your pet.