INSPECTION OF COMMERCIAL FEEDSTUFFS 13 



not represent percentage of protein. It i? simply a figure which shows the quality 

 of the protein present, on a comparative basis. 



From sources we believe to be reliable it is learned that a meat and bone c crap 

 of excellent quality should have an index value of 70 to 75, one of good quality 

 65 to 70, and of average quality 60 to 65. A product with an index value of less 

 than 55 may be considered low quality. Fish meal of highest grade may run as 

 high as 80 to 87. Fish meal produced from market scrap may run as low as 58. 

 It should be noted that considerable difference is found in products which carry 

 the same name and brand. Doubtless if the history of each batch were known, 

 ample reason could be found for this difference. 



In his paper Dr. Almquist states: ''It may be pointed out that the method of 

 analysis employed provides strong evidence of the condition and type of raw 

 materials and of the effect of the manufacturing process on the quality of the 

 product. Decomposition caused by putrefaction, autolysis or poor methods of 

 manufacture is reflected in a decrease of the copper-precipitable fraction and an 

 increase in the phosphotungstic-ac'd-precipitable fraction. The inclusion of 

 undigestible nitrogenous substances and the effect of excessive temperatures 

 introduce an unduly large undigestible fraction. An increase in the cartilage, 

 connective tissue, skin and bone content causes a corresponding increase in the 

 hot -water-soluble protein nitrogen. The same is true when the 'stick' is included 

 in the final product. Finally, the presence of much nitrogen in the lorm of am- 

 monia, amines, urea and similar types of non-protein nitrogen causes a wide 

 discrepancy to appear between the summation of the nitrogen accounted for by 

 the copper and phosphotungstic acid treatments and the total nitrogen. It should 

 also be pointed out that the analytical scheme which was employed does not 

 detect the presence of toxic substances." 



There is nothing particularly disturbing in the results obtained. While con- 

 siderable variation is found, with few exceptions the material examined equals 

 or exceeds accepted standards of protein quality. However, with prospective 

 shortages of meat and fish products, considerable vigilance should be exercised 

 in the selection of such products by manufacturers of mixed feeds. 



