/l/ Kilocalories. These values represent the approximate amount of food energy actually available to 

 and capable of use by the animal from the food absorbed. If P, C, and F represent protein, carbohy- 

 drate and fat. Ingested P,C,F - fecal P,C,F = virtually absorbed P,C,F. Grams of vlrtxially absorbed 

 PxU + Cxh + Fx9 = metabollzable Calories. These values are approximate only. The value for protein 

 (=xU) allows for a '^(yfc loss of virtually absorbed Calories in the urine (urea, hlppurlc acid, etc.). 

 In animal husbandry, and In this table, metabollzable Calories are calculated from "T. D. N." ("total 

 digestible nutrients") by multiplying grams T. D. N. by k. /2/ Air-dried (90^ dry weight). /j/ Di- 

 gestible, /k/ 0.0006 mg 3-carotene = one I. U. /5/ Probably synthesized by the horse. /6/ A generic 

 term Including cyanocobalamin {vitamin B^2^ ^"^ ^^^ hydrogenation product (known variously as B]^2a ^^ 

 ^12bJ which has approximately the same biological activity. /7/ 0.025 ug calciferol = one I. U. Nor- 

 mally supplied by exposure to direct sunlight or by ingestion of sun-dried roughages. /6/ A generic 

 term for alpha-, beta-, delta-, emd gamma-tocopherols. /9/ Folic acid Is not a chemical entity, but a 

 generic term for pteroylglutamic acid (folacin), vitamin M, vitamin B^., factor U, L. casei factor, 

 Norite eluate factor. /lO/ The anti-hemorrhaglc factor. A generic term for vitamin K^ (2-methyl-5- 

 phytyl-l,U-naphthoqulnone) , synthetic vitamin K (menadione = 2-methyl-l,U-naphthoquinone) , and vita- 

 min K2 (2-methyl-3-difamesyl-l,U-naphthoquinone). /ll/ The term is used here as a generic term for 

 nicotinic acid (niacin) and nicotiiic acid amide (nicotinamide); also for pellagra preventive (P. P.) 

 factor, anti-blacktongue factor. /I2/ Includes pyrldoxlne, pyridoxal and pyridoxamine. 



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