FEEDING STANDARDS CALCULATING RATIONS 133 



proximate results, for a cow requires considerably more nutrients to 

 produce 1 Ib. of butter fat in milk low in fat than if her milk is high 

 in fat. 



184. The Savage standard. From trials at the New York (Cornell) 

 Station 18 Savage concludes that for maximum production the nutritive 

 ratio of rations for dairy cows should not be wider than 1 :6. He has 

 accordingly modified the Haecker standard by increasing the protein 

 requirement per pound of milk by from 18 to 20 per ct. His standard 

 is also simplified by being stated in terms of dry matter, digestible crude 

 protein, and total digestible nutrients. The requirements according to 

 this standard are shown in the table on this page. 



185. The Eckles standard. From experiments at the Missouri Sta- 

 tion 19 and from the work of Savage and Armsby, Eckles formulated a 

 tentative standard according to the Armsby system, showing the require- 

 ments of cows producing milk containing various percentages of fat. He 

 points out that these are but approximations, for the following reasons : 

 The digestion coefficients in use, which have been chiefly obtained with 

 steers and sheep, are too high for feeds fed in heavy rations to dairy 

 cows. This is, however, more than offset by the fact that the cow is 

 able to utilize the nutrients she actually digests more efficiently in milk 

 production than the steer or sheep does in formation of flesh. Hence' 

 the net energy values given by Armsby are too low when applied to milk 

 production. More recently Armsby prepared complete standards himself 

 on the net energy basis for dairy cows producing milk containing 

 various percentages of fat. These standards, which are given on Page 

 125, are compared with the Eckles standards in the following table. 



186. Comparison of standards for dairy cows. In the following table 

 the Haecker, Savage, Eckles, and Armsby standards are brought to- 

 gether for comparison. Haecker 's figures have been converted into 

 total digestible nutrients, as in the Savage standard. 



Feeding standards for dairy cows compared 



The Haecker and Savage standards agree in the requirements for 

 maintenance. Savage's digestible crude protein requirement for pro- 

 18 N. Y. (Cornell) Bui. 323. 19 Mo. Res. Bui. 7. 



