TERMS USED IN REPORTING ANALYSIS 



The terms used in reporting the chemical analysis of a feedingstuff 

 required by law are briefly defined as follows : PROTEIN is a collective term 

 for a considerable group of compounds, all of which contain nitrogen. In- 

 gredients high in protein are usually more expensive than the other in- 

 gredients, making protein the most important nutrient for consideration 

 in determining the com.mercial value of a feedingstuff. The nutritional 

 value of the proteins varies widely; therefore, a feedingstuff should con- 

 tain protein from several sources to insure inclusion of all essential types. 

 FAT is separated from the other components of a feedingstuff by extract- 

 ing the moisture-free sample with anhydrous ether. In such ingredients as 

 the cereals, the seed-meals, and animal products, the extract is nearly pure 

 fat. A few ingredients such as alfalfa meal contain some ether soluble 

 material which is not fat. When sulphur is present, the "ether extract" or 

 fat found is much too high since sulphur is soluble in anhydrous ether. 

 CRUDE FIBER is composed of cellulose and related compounds. Since 

 crude fiber has little feeding value, the law requires that the maximum fiber 

 be guaranteed rather than the minimum, as in protein and fat. 



There are times when it is desirable to determine the moisture or 

 water present in a feed. Any material in contact with the air will absorb 

 or release some moisture depending upon the humidity and the kind of 

 material. Since feeds are in contact with the air and since the moisture 

 content varies somewhat with the moisture of the surroundings, it is the 

 usual custom to report the analysis of a feed on the basis as it is used rather 

 then on a perfectly dry basis. The ash or total mineral matter content is of 

 value at times and is obtained by burning a sample of the feed until all the 

 carbon is removed and only the minerals remain. The nitrogen-free extract 

 contains the more soluble carbohydrates such as sugars and certain simple 

 cellulose materials. The term carbohydrates includes the nitrogen-free ex- 

 tract plus the crude fiber. The nitrogen-free extract and carbohydrate con- 

 tent of a feed is determined by calculation after the analysis for certain 

 other constitutents. The usual analysis of a feed may be summarized as 

 follows. In using the following statement, all results must be expressed in 

 terms of per cent. 



100 minus the sum of "moisture" + "ash" + "protein" + "fat" + 

 "crude fiber" equals the "nitrogen-free extract." Total carbohydrates 

 equals "nitrogen-free extract" plus crude fiber. 



The use of medicated feeds for special and specific purposes is in- 

 creasing and new drugs that may be incorporated in feeds for the control 

 of disease are constantly being studied. The use of drugs in feed must be 

 carefully investigated and meet the approval of the Food and Drug Admin- 

 istration before it is put on the market. The laboratory has analyzed many 

 of the feeds containing certain drugs during the past year and found no 

 serious deficiencies. It is thought not advisable to publish results at this 

 time since a more complete coverage is desirable. 



Research has shown the value of added trace elements, growth factors, 

 certain vitamins and other substances that will improve the growth and 

 quality of livestock. These materials appear in the mixed feeds as their 

 value is proven and the result is a product that can be fed with confidence 

 and satisfaction by the grower of livestock. 



