354 CLEAN MILK 



Supposing that we wish to determine a standard for feeding a herd 

 of cows, each weighing on the average 850 lbs. and yielding on the 

 average 25 lbs. of milk each daily: — 



We first consult Table I for standards for maintenance of cattle. 

 We find that for cattle weighing 850 lbs. the daily requirements are : — 



Digestible protein. Energy value. 

 Lbs. Therms. 



For maintenance °-45 5-6 



For 25 lbs. of milk 1 . 25 7.5 



1.70 13.10 



For cows giving 25 lbs. of milk we find that we must add to the 

 maintenance figures the required energy value in therms corresponding 

 to this milk yield. It was stated above that for each pound of milk 

 yield there will be required 0.3 therm of energy value and an allowance 

 of 0.05 lb. of digestible protein. Therefore, multiplying each of these 

 factors' by 25, and adding the results to the required standard in di- 

 gestible protein and therms for maintenance, we get the standard re- 

 quired for cows weighing 850 lbs. and giving daily 25 lbs. of milk, as 

 .above. 



Next we desire to so arrange the various food stuffs at command 

 that the proper proportion of dry matter and proteids are attained and, 

 especially, that the nutrients in the aggregate furnish the amount of 

 digestible protein and energy value required by our standard above. 



We have found that there should be 20-30 lbs. of dry matter in a 

 daily ration and at least 1 lb. of digestible protein for each 8 to 10 

 lbs. of the other nutrients (fat and carbohydrates). 



We must first concoct a theoretical ration from the food stuffs 

 at hand and then alter the ration to accord with the standard, or to 

 substitute one food stuff for another on account of greater economy. 



W,e will select the first ration on p. 72 consisting of 20 lbs. of 

 timothy, 2 lbs. of oats, 4 lbs. of gluten meal and 4 lbs. of wheat 

 bran. 



Consulting Table II, showing dry matter, digestible protein and 

 energy value per 100 lbs., we find that each of the food stuffs selected 

 contain of these, as will be seen below : 



Protein, lbs. Therms. Dry matter. 



Timothy, 20 lbs .41 6.71 il-3 



Oats, 2 lbs .17 1.33 i^ 



Bran, 4 lbs .04 1.92 -i.c 



Gluten, 4 lbs .08 3.17 ■> ,j 



Total 1.78 13.13 26.3 



