132 FEEDS AND FEEDING 



Haecker made an important advance in the formulation of rations 

 for the dairy cow. He was the first to show that the nutrients required 

 for her nourishment should vary not only with the quantity of milk 

 yielded, as was taught in the Wolff-Lehmann, the Kellner and the feed- 

 unit standards, but also with the quality of the product. The allowance 

 of crude protein recommended is also considerably lower than advised 

 in the original Wolff-Lehmann standards. Haecker 's recommendations 

 are given in comparison with other modern standards for dairy cows in 

 the table on Page 133. Haecker expressed his standards in terms of 

 digestible crude protein, digestible carbohydrates, and digestible fat, 

 but in this table the recommendations have been simplified and are given 

 in terms merely of digestible crude protein and total digestible nutrients, 

 for as we have already learned in previous chapters, carbohydrates and 

 fat in general perform the same functions in the body. Likewise, when 

 more protein is supplied than is needed for the repair of the body tissues 

 and the formation of the protein in the milk, any additional amount 

 may be used for the same purposes as the carbohydrates and fat. 



This table shows that, according to Haecker, the 1,000-lb. cow requires 

 0.700 Ib. digestible crude protein and 7.925 Ibs. total digestible nutri- 

 ents merely to maintain her body, independent of the requirements for 

 the production of milk. The maintenance requirements of cows of other 

 live weights are proportional to their weights. For example, to find the 

 maintenance requirements for a 1,200-lb. cow, these figures are multiplied 

 by 1.2. The table also gives the amounts of digestible crude protein 

 and total digestible nutrients required for the production of a pound of 

 milk of the various fat contents, after the needs for mere body mainte- 

 nance have been met. For instance, a cow requires 0.047 Ib. digestible 

 crude protein and 0.284 Ib. total digestible nutrients in addition to the 

 maintenance requirements for each pound of 3.5 per ct. milk she pro- 

 duces. If her milk contains 5 per ct. fat, the amount of nutrients 

 needed for each pound of milk produced is much larger, being 0.060 Ib. 

 digestible crude protein and 0.398 Ib. total digestible nutrients. By 

 multiplying the requirements for each pound of milk by the number of 

 pounds yielded daily and adding the result to the requirements for 

 maintenance, the total amounts of nutrients needed by an individual 

 cow are readily found. 



183. The Woll-Hnmphrey standard. At the Wisconsin Station Woll 

 and Humphrey prepared convenient tables showing the feed require- 

 ments of cows of different weights and producing various amounts of 

 butter fat per day. For example, the requirements of the 1,000-lb. cow 

 producing 1 Ib. of butter fat daily, according to these tables, are 22.3 

 Ibs. dry matter, 2.02 Ibs. digestible crude protein, and 15.4 Ibs. total 

 digestible nutrients. For the same cow yielding 1.5 Ibs. fat daily, 27.3 

 Ibs. dry matter, 2.86 Ibs. digestible crude protein, and 19.2 Ibs. total 

 digestible nutrients are' recommended. 17 This system gives only ap- 



1T Table as revised by Humphrey, unpublished data. 



