Alfalfa (or lucerne as it is more commonly known in the UK) is part of the legume family of plants and is widely regarded as a superfood. It is an excellent natural source of a whole host of nutrients including plenty of vitamins and minerals - most notably iron, magnesium, manganese, vitamin A, C, E and several B vitamins, as well as good quality fibre.
Animal Fat / Oil
In nutritional terms, 'fat' and 'oil' are two terms for the same thing. 'Animal fat' is very vague and can refer to any fat from any animal source but in general this term is used for the fats that are left over when meat meal is made. As always, it is best to look for foods which specify which animals the fats come from.
Like all animals, dogs need a certain amount of fat from their diet to survive. Fat is found naturally in all types of meat but because dogs find animal fats so irresistible extra is often added to dog foods. For fussy dogs it is often a good idea to look for foods with higher fat levels but be careful as too much fat can lead to the same kind of problems as in humans.
Artificial preservatives and antioxidants
A preservative is any ingredient added to a food to slow down spoilage. Antioxidants are an important branch of preservatives as they inhibit the oxidisation process which turns fats rancid. Both preservatives and antioxidants can come from natural sources (such as vitamin E and rosemary oil) or be artificially created. Here we will talk only about artificial preservatives and antioxidants.
Although artificial preservatives certainly work at slowing down decomposition, there are wide ranging concerns over their effects on health. Ethoxyquin (E324), for example, has been linked to the development of allergic reactions, skin disease, behaviour problems and far worse conditions. Likewise, the antioxidants BHA (E320) and BHT (E321) have long been suspected of contributing to cancer. Another common preservative, potassium sorbate (E202), is listed as a skin, eye and respiratory irritant.
Needless to say, while there is any uncertainty over their side effects, these ingredients are certainly best avoided.
If a food contains artificial preservatives or antioxidants it must be stated somewhere on the label. They may be listed in a number of ways and are not always easy to spot: 'preservatives'; 'EU permitted additives'; 'BHA and BHT'; and 'E320 and E321' are all ways of listing the same preservatives. They may also not appear on the ingredients list at all but be found at the end of the typical analysis. If you want to be completely sure, look for foods that clearly state 'no artificial preservatives'.
Barley is commonly used in dog food in a variety of forms. Once cooked it is easily digested by dogs and provides abundant fibre and several micronutrients including selenium and copper. Whole grain barley is the best form as it retains most of its nutrients.
In humans, barley gluten has been indicated as a problem ingredient for celiacs so if you are looking for a gluten free food, it would probably be best to steer clear of barley as well as wheat.
Barley grass is made from the leaves of barley plants and is becoming popular as a health supplement for both humans and dogs. It contains a high density of a wide range of nutrients and is sometimes suggested as a natural anti-oxidant and anti-inflammitory. Like oat grass and wheatgrass, barley grass does not contain the sometimes problematic proteins found in barley grains and so it can be given to cereal sensitive dogs.
Beef is a high quality meat source for dogs. Some pet food manufacturers have reported that it is more likely to cause dietary intolerance but solid evidence of this is hard to come by.
Red meats like beef contain higher levels of trans-fats and cholesterol which should be kept to a minimum if your dog has a history of health problems. Red meats also contain higher levels of purines and other minerals (especially in the 'meal' form due to the higher bone content) which are best avoided in dogs with urinary conditions.
As with all meats, the beef used in dog food can come in a number of forms of varying quality and nutritional value.
Like all meats, when an ingredients list features just 'beef' (as opposed to 'dried beef', 'beef meal' etc) it usually refers to fresh beef.
Bone meal or ground bone is added to some dog foods as a natural calcium and phosphorous supplement. Its definition is very vague as it could come from any animal so if your dog is intolerant to a specific meat, bone meal is probably best avoided.
Like evening primrose oil, borage oil is an excellent source of gamma-linolenic acid (GLA) which has an anti-inflammatory effect and is often recommended in the natural treatment of arthritis as well as certain skin conditions.
Brewer's yeast is one of the best sources of natural B vitamins including B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin) and B9 (folic acid). These vitamins have a wide range of functions in dogs including aiding digestion, supporting of the nervous system and keeping the skin, hair, eyes, mouth, and liver healthy.
Yeast is also a good source of protein. It is known as a 'complete protein' since it contains all nine of the essential amino acids needed by dogs.
Calcium carbonate is widely used in dog foods as a calcium supplement and less frequently as an acidity regulator, colouring, anti-caking agent or stabiliser. It can be derived from a number of sources including bone meal, oyster shells, limestone, and dolomite (clay). Calcium carbonate can also help to ease symptoms of irritable bowel syndrome (IBS) but excessive calcium can have serious side effects so adding extra to a complete food is generally not recommended.