The value of oats as an animal feed has been recognized for many years. Its position in our livestock feeding program is shown by the fact that among the cereal grains grown in Canada, oats production is exceeded only by that of wheat. During the crop year of 1951 production amounted to 488 million bushels and during the same period approximately 372 million bushels were used as animal feed. Oats holds a unique position in the Canadian livestock feeding program that cannot be filled by any other grain.

Since approximately the turn of the 20th century the scheme most commonly used by animal nutritionists on the North American continent to describe quantitatively the useful or available energy of a feeding stuff to an animal has been that of Total Digestible Nutrients (TDN). The calculation of a TDN value involves the following steps: l) fractionation of a dry feed by the Weende analysis into crude protein, ether extract, carbohydrate and ash, of which all but ash are potential energy sources; 2) the application of appropriate digestion coefficients to determine digestible nutrients; 3) and finally a weighting of the digestible nutrients by a scheme of metabolizable calories developed simultaneously by Hills and associates, and by Woll and Humphrey (Maynard, 1953).

For a number of years, the Macdonald College Pasture Committee has been directing projects designed to determine the feeding value of forages. The importance of this work can scarcely be overemphasized, since forages make up a large portion of the rations of cattle and sheep. A completely adequate method of evaluating forage feeding value has yet to be described. At present, forages are evaluated primarily according to their chemical composition and their content of total digestible nutrients (TDN). Criteria such as these are adequate when forages of equal acceptability to the animal are being evaluated. However, if forages are voluntarily consumed in different amounts by the animal, the percentage content of TDN, protein, calcium, etc., will not provide a true evaluation since the total intake of any one of these entities over a specific period of time will be unknown.

The supplementary protein value of several combinations of a refined law fiber corn gluten meal and a refined soybean oilmeal in supporting growth of weanling rats was determined using semi-synthetic diets. None of the combinations gave a significant supplementary protein effect. It was noted, however, that replacement of 40 percent soybean oilmeal protein with corn gluten meal protein resulted in a product equal in protein efficiency to soybean oilmeal itself. In an attempt to utilize the milling excess of corn bran, a high fiber low protein corn bran feed was produced on an experimental basis. ln digestibility trials with sheep the corn bran feed was found to be less digestible and yielded less useful energy than commercial corn gluten feed. On the other hand, corn bran feed yielded more useful energy than a good quality legume hay.

This investigation is part of a project which was recommended by the Committee on Calorie Conversion Factors and Food Composition Tables of the United Nations Food and Agriculture Organization (1947). One of the aims of the Food and Agriculture Organization is to promote international agreement regarding a common basis for the calculation of the nutritional value of foods. The first consideration has been given to calories.

This knowledge has provided the background for the production of more economical rations and for improvement in management techniques. [...]

In 1947 the F. A. O. Committee on Calorie Conversion Factors and Food Composition Tables met in Washington, D. C. to "develop principles on which average food composition figures used by individual countries could be based." The recommendation of this committee was that further research should be carried out "on energy - yielding constituents of food and the derivation of calorie values." As part of the investigation of the physiological fuel values proposed by Atwater in 1899 and widely used since that time for determining the useful calorie value of human foods, a comparative digestibility study involving humans, sheep, swine, rats and guinea pigs was begun in the Department of Nutrition laboratory at Macdonald College in 1949.

Chromic oxide (Cr2O3) was found to be satisfactory for determining the digestibility of rat and pig rations. For sheep, the index was useful only if the ration contained 35%, by weight, of a ground non-roughage material. Limitations were pointed out in the regression method of determining indirectly the digestibility and metabolizable energy of sheep and pig feeds. Associative digestibility complicated these determinations. It was also emphasized that relatively large amounts of supplement must be added to a basal ration to obtain reliable digestion coefficients for the former. In calculating the physiological fuel values of a feed for sheep, need was indicated for a specifie determination of the urinary and gaseous energy lasses. Following a change in sheep or pig ration composition, a length of time, considerably longer than the usual preliminary feeding periods used for these species, was required before digestibility became constant and maximum.

Using white rats, a feeding trial in which levels of fat and of mineral (bone char) supplement were varied showed apparent digestion coefficients of better than 92% for bydrogenated peanut oil or m.p. 42°C. At a ten percent level in diets, this fat was more digestible than at 20%. Ether-extraction gave higher coefficients on the average than did titrimetric estimation of total fatty acids. This discrepancy was clearly due to the failure of diethyl ether to measure soaps by conventional extraction procedures, and such soaps were shown present in feces to an extent dependent on the levels on fat and of calcium in the diets.

No description available.