Quoted by John W. Patton, 'A Discussion of the Proposed Dog Food Standards', Veterinary Medicine 30 (3) (1935), pp. 128-132.
Description:

'In a recent report of the National Dog Food Manufacturers' Association, prepared for the executive office of the Code Authority of the dog food industry, by Dr. George R. Cowgill and Mr. William E. Anderson, Sterling Hall of Medicine, Yale University, we find a few recommendations which appear worthy of discussion.

This writer appreciates the difficulty confronting the framers of adequate standards appropriate for dog foods and takes this opportunity to compliment the administrative authority of the National Dog Food Manufacturers' Association on their choice of scientific advisors and, in turn, to compliment these scientists on their progress in formulating these standards. Having no interest in the manufacture or sale of commercial dog foods, the present writer has, however, a keen interest in an augmented scientific knowledge of canine nutrition, in all measures for promoting a broader appreciation of the importance of nutrition and a greater availability of nutritious commercial dog foods.

It is approximately three years since our first articles on the status of commercial dog foods appeared in this magazine. From the first, we have stressed biological values. Such is our present attitude.

To quote these proposed standards of the National Dog Foods Manufacturers' Association:

With respect to the vitamins, the following minima are suggested:

Vitamin A - Not less than 15 international units per 100 calories.

Vitamin B (B1) - Not less than 2 international units per 100 calories.

Vitamin D - Not less than 4 international units per 100 calories.

I am fully in accord with the evident attempt to standardize the units of vitamins that a dog food should contain. I do not see, however, how we are going to do this, without first standardizing the number of calories a dog food shall contain.

We observe in our analysis of 10 representative brands of canned dog food (table I) that the calculated calorific values vary between wide ranges. One brand (C) contains 364.34 calories and another (L) contains 599.28 calories per pound can. The manufacturer of brand C, to comply with these standards, is required to provide approximately 55 units of vitamin A, seven units of vitamin B1, and 14 units of vitamin D per can. His competitor, who makes a food of higher calorific value - for example brand L - is required to provide approximately 90 units of A, 12 units of B and 24 units of D, or to have about 65 per cent greater vitamin content per can to attain the same standard. This places a penalty on the manufacturer of brand L - the high calorific food - and gives an advantage to the manufacturer of the food of the lower calorific value, brand C. Be it remembered this is a highly competitive market, where price cutting is rampant.

Basing standards upon calorific content will not alter the fact that the unit of measurement still remains "a can of dog food." A can is a can to the average dog owner and he feeds it accordingly - buys it that way too. To him, it is one can, more or less, to a meal or per day. If the dog is fed one can of brand C per day, he will, obviously, get but little more than half the vitamin units he would get were he fed brand L. I would propose that every can of dog food, either with or in the absence of uniform calorific content, contain a unitage of vitamins sufficient in amount, on a kilo basis, to provide adequately for the average dog's nutritional requirement of these vitamins. [128]

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[129] Of less practical importance, but of considerable scientific interest, the following statement in the proposed standards intrigues one:

Vitamin C: Inasmuch as this factor is not required by the dog, it may be omitted from the food.

Does the dog not require vitamin C at all, or can he dispense with it in his food for the reason that he manufactures his own vitamin C? My understanding is the latter.

In another paragraph pertaining to mineral standards, we find the following:

Inasmuch as the healthy organism regulates its food intake according to its energy needs, it is most desirable that the requirements of varying dietary essentials be expressed in relation to its energy-yielding value of the diet. Protein should be present in such amounts as to furnish not less than 15% of the total energy yielded by the food.

There is nothing in this standard to prohibit a manufacturer from using protein of vegetable origin or any other nitrogenous substance regardless of its nature or its biological value.

To fail to qualify protein leaves a loophole to even exclude meat, or meat by-products, and does not differentiate proteins of high or low biological value as perhaps a biological standard should. I would suggest that the standard for canned dog food specify a minimum of animal (meat) protein and place a minimum biological requirement on protein in general. Protein in an amount sufficient to furnish 15% of the total energy is a step in the right direction: however, is not this percentage based on human dietary requirements? Will a [129] manufacturer [130] of dog food who abides by this standard necessarily meet the protein requirements of dogs?

In still another paragraph, we find:

It is our opinion that it is unnecessary and perhaps unwise to make any specific requirements concerning the amount of carbohydrates and fat in canned dog food, or the ration of these foodstuffs to each other.

In my opinion it is both necessary and wise to incorporate some standards for both carbohydrates and fat. It is certainly unwise to load a canned dog food with whole wheat or barley, for instance, or with any other carbohydrate either hard to digest or relatively undigestible [sic], under normal conditions, in the intestinal tract of the dog. We might at least state that no carbohydrates shall be used in the canned dog food that pass through the digestive apparatus of a dog unaffected by digestion - as do both whole wheat and barley.

As for that, I see no good reason why we cannot get away from the fat phobia that has affected the average dog owner and dog food manufacturer and set a standard of, say, four to five percent - more in keeping with the optimal utilization and supplemental value of this ingredient. The analyses in table I furnish a case in point. In view of the great palatability of fat for dogs and the high degree of utilization of fats by this animal, a fat content of less than one half of one per cent (actually shown by one food) seems a sufficient refutation of the statement ". . . it is unnecessary and perhaps unwise to make any specific requirement. . ."

In regard to the suggestion as to crude fiber, we quote the following pertinent paragraph:

It is suggested that the standard with respect to roughage be fixed at not more than 1 milligram per calorie of crude fiber and/or other indigestible material including keratin, which is present in great abundance in fish scales, horn, and other epidermal appendages.

By reference to table 2, we observe how the recommended crude fiber compares with that in representative brands of canned dog food. The majority of these brands exceed, greatly, the maximum suggested. It is quite probable that it may be difficult to produce canned dog foods containing, as most of them do, a relatively high percentage of carbohydrates, cereals and vegetables, and keep the crude fiber down to a maximum of one milligram per calorie. It must not be forgotten that canned dog food is to a considerable extent, a cereal as well as a meat product. [130]

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[131] Nowhere in this report on standards do I find more than a mention of vitamin B2 (G)[.] I cannot believe that this important vitamin was overlooked or purposely left out of the standard; for its importance, in a broad nutritional sense, is too well known to those framing these standards. Under present conditions it is most critical in the field of canine nutrition - perhaps for the reason that we have over-looked its importance too long - and further, many dog foods lack this vitamin. I am not in a position to state what the minimum intake of this vitamin should be. However, we should acknowledge its importance and acknowledge it in our recommendations. Goldberger, long ago, showed the disaster that supervenes upon its absence. Possibly a minimum standard for vitamin G in dog foods can be set from out knowledge of this vitamin in general nutrition.

I have in mind several canned dog foods now on the market, the growth curves for which vary directly with their vitamin G content. To eliminate it from consideration is, in my opinion, a grave error. to omit it entirely from a food is to condemn to death most dogs fed exclusively upon that food, as Goldberger has shown.

In other paragraphs, we find the following recommendations regarding minerals, especially calcium and phosphorus:

It is more difficult to formulate exact and correct standards of intake of the mineral nutrients mentioned above. Standards have been offered for the human species and these might be taken as a basis in attempting to formulate minima for the dog. From studies made on different species it is evident that those which are smaller in body size have relatively greater nutritive requirements, certainly for some, if not all, of the dietary essentials. If the two foregoing facts are utilized, one arrives at the following suggestions of minima for three of the most important mineral nutrients:

Calcium: Not less than 30 milligrams per 100 calories.

Phosphorus: Not less than 50 milligrams per 100 calories.

Also the following reference:

The literature on nutrition suggests that it might be desirable to specify that calcium and phosphorus be present in an optimal ratio, such as, for example, that characteristic of milk calcium-phosphorus equals about 1:2.

Here we have a recommendation of 30 milligrams calcium per 100 calories and 50 milligrams of phosphorus per 100 calories - or a calcium-phosphorous ratio of 3:5. In the second instance ewe find yet another ratio suggested, 1:2, and a further reference to a calcium-phosphorus ratio equivalent to that of milk.

Milk is a good yardstick, perhaps, but what milk? When one thinks of milk in connection with canine nutrition, one naturally thinks of the milk of the bitch. I know of no normal milk with a calcium-phosphorus ration of 1:2. Perhaps human milk with a ratio of 2:1 was in mind.

The calcium-phosphorus ratio of both dog's milk and of new-born puppies [note: 'Forbes, Keith. T. Bul. 5, Ohio Exp. Sta., 168, 1914.'] closely approximates a ratio of 1:5:1 or 3:2. In our opinion this ratio is more suitable for dog foods than either the 1:2 or 3:5 ratios suggested. Seldom indeed do we find the calcium content of milk less than that of phosphorus, except in some herbivorous animals that commence to eat soon after birth.

Further, a calcium-phosphorus ratio of either 1:2 or 3:5, as suggested, would seem inadequate at the critical stages of growth or lactation of dogs. We have in mind also the calcium-phosphorus ratio and vitamin D, and the availability of both calcium and phosphorus.

The canned dog food industry is undergoing a transition. Canned dog foods of the immediate past were products chiefly of the canner and, to a very limited extent, of the meat-packer.  Canned dog foods of the immediate past were products chiefly of the canner and, to a very limited extent, of the meat packer. The latter are now very much interested in canning dog food. In the near future we shall, probably, see the packing industry also a principal part of the dog food industry. Raw material may be difficult of procurement by others. There must be left no loopholes in the standard, that will enable any manufacturers not having a steady and uniform source of raw material (meat) within his control to evade either the standard or the issue of nutritious dog foods. Failing to qualify proteins leaves such a loophole. It permits a canned dog food without meat, or meat by-products: a condition hardly conceivable, at least, to the dog owner.

Since the various brands of canned dog food will probably vary biologically, irrespective of standards proposed or established, it would appear that some effort should be made to grade dog foods according to nutritive quality – i.e., on a biological basis. It is conceivable that, irrespective of standards, there will be some manufacturers of dog food who will be satisfied to adhere to minimal standards and others who will continually strive by the application of independent nutritional research, to produce superior dog food. It would be both unfair and unwise to stifle any such advancement of either knowledge or product by classifying such products on the same level with others adhering only to minimal standards.' (129-132)